9 ms·

My fan worked fine, so I gave it WiFi

222 points by woolywonder 11mo ago

monerozcash 11mo ago
[flagged]
deleted 11mo ago
[deleted]
kylehotchkiss 11mo ago
Oh no don’t tell vornado this is possible and give them an enshittificafion pathway for their products
- Eric_WVGG 11mo ago
  IMO anything with unnecessary digital interfaces is already down the path. I have a Vornado fan that I would love to automate with a simple wifi-enabled plug, but due to the digital on/off/speed button, when you cut-off and restore power to the device, it stays off. If it had a dumb analog dial or switch, it would both be fine for normal use, and could be easily, cheaply made "smart." They do sell wifi-enabled fans; none of them are in a form factor that would fit in my window. I'm not even alone in this gripe, lots of other maniacs have done the hard work of conversions. Unfortunately I'm not confident enough in my soldering skills to try :\ https://www.reddit.com/r/electrical/comments/vaiskf/bypass_pushbutton_controls_on_vornado_fan_rewire/ https://www.reddit.com/r/electrical/comments/vaiskf/bypass_p...
hnuser123456 11mo ago
I actually like this idea. Makes more sense than smart fridges. Would be cool if this ESPHome thing worked with RP2350/Rpi Pico 2.
- moffkalast 11mo ago
  Could tie it to a thermometer and turn it on automatically on hot days. Very cool.
  - madaxe_again 11mo ago
    Ideal for a beer fridge. Is today a beer in the sun day? If so, chill those bad boys. Otherwise, save the energy.
    - moffkalast 11mo ago
      Ah yes, buying tens of dollars worth of hardware to save cents worth of power. What being a hardware hobbyist is all about!
- 05 11mo ago
  It's there, but you have to configure a custom platform due to politics between PIO and RPI. rp2040: board: rpipico2w framework: platform_version: https://github.com/maxgerhardt/platform-raspberrypi.git#develop version: dev esphome: platformio_options: build_flags: - -DPICO_VSYS_PIN=29 [0] https://github.com/esphome/feature-requests/issues/2837#issuecomment-2544595373 https://github.com/esphome/feature-requests/issues/2837#issu...
ttshaw1 11mo ago
I don't like the notion of doing speed control by putting a digipot in series with a motor. It worked because the fan happened to be low enough power but it doesn't seem like the author gave thought to the power handling capability of the digipot. If the fan happened to be beefier he's letting the smoke out with this design. Plus, this is more complicated than just doing PWM.
- _ihaque 11mo ago
  Based on the description of the wiring to the motor (24V, GND, POT1, POT2, NC), it doesn't sound like the original setup would have been drawing much power through the pot either -- there's probably something else on the other end of that wire that is doing modulation based on the sense resistance, and the motor is itself drawing power from the 24V line. So while it's true that there should be a check for the allowable limits on the digipot, I don't think it's actually being used to sink much power.
  - 05 11mo ago
    > there's probably something else on the other end of that wire that is doing modulation based on the sense resistance And it would have been great if that arbitrary assumption had been tested by the OP and the results were documented in the article so that they wouldn't come off as somewhat clueless as to the limitations of their design.. oh well.
    - anamexis 11mo ago
      From the HN guidelines: > Be kind. Don't be snarky. Converse curiously; don't cross-examine. Edit out swipes. > Don't be curmudgeonly. Thoughtful criticism is fine, but please don't be rigidly or generically negative.
      - TylerE 11mo ago
        These passive aggressive posts are a far worse violation of the HN Guidelines than what they're in reply to almost all of the time - and this is no exception.
NegativeLatency 11mo ago
ESPHome and homeassistant have been really great, just like a nice breath of fresh air in a world of cloud saas stuff.
- ssl-3 11mo ago
  Home Assistant does great at tying all kinds of things together. People had a habit of leaving the basement lights on here. Now they turn themselves off after a timer expires, and also whenever nobody's home. Using HA and a cheap Shelly relay (chosen for form factor), I was able to do this while retaining the existing lighting circuits, light switch, and the lights themselves. It works perfectly, is completely local, and the end-user UI is completely natural. Toggle the same plain-Jane light switch that has always been there at the top of the basement stairs and the lights change state. (UI doesn't get more intuitive than that.) Or: Fans. This house has a good furnace and central aircon, but the ductwork doesn't really extend upstairs. By default, this makes the upstairs-parts very hot in the summer and cooler than I'd like in the winter -- even though it's nice downstairs during all seasons. I fixed that to my satisfaction by putting a fan on the landing that is controlled by an inexpensive smart switch, just to improve circulation. HA runs this show; the fan runs when the HVAC is doing something, and whenever people are home and it is either too hot or too cold upstairs (based on a temperature sensor). It's not a perfect solution, but it's kept the temperatures sane (and provided logging to prove it), it was cheap to implement, and it is cheap to run. I already had the parts kicking around; it just took software and time. (The best option for efficiency and comfort is probably installing mini-splits up there, but... sheesh, that's into the realm of orders-of-magnitude more expensive. Maybe some day.)
  - NegativeLatency 11mo ago
    I'm curious how you used the shelly? They look neat but I'm not sure how people are wiring them into existing switches.
    - ssl-3 11mo ago
      Good question. I put the Shelly relay in a pre-existing junction box in the basement. Previously, this box worked like this: There were romex cables for power/neutral, lights, and the switch itself all inside of that box. The switch, located elsewhere, interrupted power to the lights. (This isn't necessarily the most-typical arrangement, but it's how it is in the house I've got.) Currently, the box works like this: We still have romex cables for power/neutral, lights, and the switch itself inside of that box. That part hasn't changed at all. But now the Shelly relay interrupts power to the lights. Thus, the lights are always controlled by software. And the light switch? That just provides an input that is acted upon by a software script. The script (which runs internally within the Shelly relay) only does 3 things: 1. If relay is on and switch toggles, turn relay off. 2. If relay is off and switch toggles, turn relay on. 3. If relay is turned on by any mechanism, start timer, and then turn off after timer expires. (Plus other useful timer mechanics like resets on additional toggling, but you get the idea.) --- It's easiest to think of a Shelly relay like a replacement for a light switch, but that's kind of a limiting way to think about it because that line of thought strongly implies that it should to be located where the switch is. And while it certainly can be installed that way, in practice it really doesn't have that limitation. For my unfinished basement, there's no neutral at the light switch location so using a regular smart switch didn't pan out. (I could have added a neutral but that would have meant using more parts and getting into some drywall and paint.) Instead, there's that neat (who am I kidding, it's a mess) junction box I that described, up on the ceiling where all of the things come together... So that's where I put the relay. Or: There's a box behind a light fixture (well, there "should" be anyway). Often, this box will have the same functions available inside that my junction box happened to have. Power, neutral, light(s), switch input. A relay can go there. But many houses do have neutral at the light switch location, so a relay can go there instead. Power/neutral feeds in, power for lights feeds out, with a switch (and/or relay!) in the middle. All in one accessible box on the wall. This matches the easy-to-think-of scenario. (IIRC all new homes are supposed to be this way in the US, but...) It's (usually!) just a matter of finding the right physical location in which to install the relay. (Note: None of this is intended to be an exhaustive list of variations. Things can and do get weird with household wiring, and regional variations of what "normal" means can vary quite tremendously.)
05 11mo ago
Why is there level conversion though if the digipot (MCP4141) is 2.7V to 5.5V? Personally I'd just use breadboard, it's just a 8 pin IC and a ESP module, for a one-off hack..
- announcer4614 11mo ago
  Hey, author here. There's a line in the digipot datasheet that says the voltage on the A/B/W pins must be within -0.3V to VDD + 0.3V. The fan's line for the wiper pin is 5V, which would fall well outside of that if I gave the digipot's VDD 3.3V.
  - 05 11mo ago
    Thanks. Thinking more about that, might have been easier to just use 5V tolerant esp8266 :)
    - announcer4614 11mo ago
      Fair point, I hadn't thought to consider that aspect of the ESP8266. I mainly opted for the shiny new ESP32-C6 with the idea that I might one day set it up to use Thread instead of WiFi.
IvyMike 11mo ago
I've been toying with a variant of this project for my Honeywell home air filters. I have one in all my "big" rooms, and I like to keep them running at a low speed most of the day. But I also have time-of-day energy pricing, and it would be nice to automatically turn off (or at least slow) my air filters during the 5pm-8pm window. This project inspires me to at least look into the feasibility of adding that functionality myself.
- NegativeLatency 11mo ago
  Depending on your air filter you might be able to just use a smart plug, I went down a similar route this summer before realizing that mine would remember their power state and settings when powered off. So now I just have them plugged into a few smart plugs with automations in homeassistant
  - reaperducer 11mo ago
    Why not just use a dumb timer plug from a hardware store? Ten bucks, and completely hacker-proof: https://www.acehardware.com/departments/lighting-and-electrical/timers-and-lighting-controls/timers/3001316 https://www.acehardware.com/departments/lighting-and-electri... $16 if you need a remote control: https://www.acehardware.com/departments/lighting-and-electrical/timers-and-lighting-controls/timers/3001320 https://www.acehardware.com/departments/lighting-and-electri... Or $17 if you want to get all digital and fancy: https://www.acehardware.com/p/3001323 https://www.acehardware.com/p/3001323
    - NegativeLatency 11mo ago
      Sure those work, I've tried them before, but I find them more fiddly and less fun to program than homeassistant. Also I can easily turn them on or off from my phone which is nice if I'm feeling lazy.
  - XorNot 11mo ago
    This is what I do with my dehumidifiers. It's been working so well I was actually surprised one night when the dehumidifier in the bedroom turned itself on from the automation (which I have set to do after dark if humidity is higher then 70%). It had been within tolerance for ages and I just hadn't had to even think about it.
uoaei 11mo ago
I love upgrading simple home appliances with homebrew smarts using ESPHome so that they retain their original interface. I've mostly done lights that are still correctly switched at the original wall switches but up next is my fan and toaster oven! Then to tackle the thermostats.
supportengineer 11mo ago
The next step would be to monetize it with ads, and put some of the features behind a monthly subscription. Premium oscillation package, only $9.99 a month.
- alexchantavy 11mo ago
  Need $150 a month to add SSO though
  - bigiain 11mo ago
    Single Sweat Off is an Enterprise Only requirement.
- iambateman 11mo ago
  $9.99 is for a single user. Extra users cost $14.99 each sold in packs of 5 with a three year minimum contract.
- nrhrjrjrjtntbt 11mo ago
  Premium oscillation package. We still talking fans? Or only fans?
  - ninju 11mo ago
    OnlyFans...I see what you did there :-)
- celloductor 11mo ago
  what abut adding a gps in there, you can then use it in different rooms only if you pay a $5 multiple location unlocking fee
jonhohle 11mo ago
This is amazingly cool. Did you consider putting a rotary encoder on the PCB to maintain local control over the speed?
- announcer4614 11mo ago
  That's exactly what I did :) and a convenient thing I realised afterwards is that the push-button function of the rotary encoder gives me the ability to turn the thing on and off with my foot!
  - jonhohle 11mo ago
    (Facepalm) I looked at the pictures and skimmed, missing the encoder part. Awesome!
mihaaly 11mo ago
I purchased a Phillips fan in a shopping spree. It was hot outside, needed something, did not pay much attention beyond that it worked and was not noisy. At home my eyebrows went halfway on my forehead seeing that there is a remote and the remote is supposed to be my mobile! Need to download the app for it, connect the fan to the Wifi, but it also had bluetooth for some reason. No way Jose! Yet, it was so incredibly stupid like 4K zoom camera in a hammer that I had to try. Carefully. Data collection notice in the app shop is not promising, not at all. Location data, ID, I do not remember in full but perhaps contacts too? Unsure, but a lot. Anyway, will not enable access to most, airplane mode on, no bluetooth device in sight, so went ahead and installed the app, router disconnected from the internet, then run it. First thing: refusing access to location. App: sorry, you cannot use me if I cannot access your location, network, and my mothership. And it stops. Big laugh, delete the whole thing. Leaving feedback for other customers about this incredibly stupid intrusion. Then I got answer from Phillips! Something along the line: "This is for the best interest of our customers, we need your precise location so we can share personalized pollen and climate data and whatnot, we absolutely must insist this!" For a fan! Meanwhile the fan has physical buttons on it, can adjust speed, timer, and the cycle. Not completely useless. However some buttons need two press to register the action once. Beeps twice, does thing once. Likely some interference with The App, need to make sure that I am in the same room with the fan with a warning press and then the real press, or whothef knows what was in the head of these guys when they put this piece of thing together!? But really, are they nuts? Ruining use along pollen data?! Are we already living the movie Idiocracy when it is about the Phillips product design department?! Did they loose all sense with reality? I am sure they already pushing through some new AI function for this very fan and are sad that mine cannot connect to the mother ship through satellite or something just so the update can be pushed to it learning my breath patterns for optimal fan speed. They are nuts! They are nuts!
- tzs 11mo ago
  > Need to download the app for it, connect the fan to the Wifi, but it also had bluetooth for some reason. Bluetooth could be there for initial setup. To connect the fan to WiFi you have to somehow get the WiFi credentials to the fan. There are a few ways to do that. One of the most common is for the device when it has not yet been set up to make itself available over Bluetooth. The app can then connect to it and give it the WiFi credentials. Another common way is for the device to create its own WiFi network with a name that the app can somehow recognize. The app can then find that network, connect to it, and use it to talk to the device. I don't think this is as popular as the Bluetooth method, probably because it used to require that the user go to their network settings and connect to the device's WiFi network. Plus, when they are connected to the device they are not connected to their "real" WiFi which could disrupt other apps. However, newer Apple and Android mobile operating systems provide ways for applications to change the network connection in the background or with minimal interaction, which makes this method more friendly so maybe it will become more popular. There also are supposedly some IoT devices that use WPS (WiFi Protected Setup), where you bring the device near your router, press the WPS button on the router, then press the WPS button on the device, and magic happens to add the devide to your network. I've never actually had any device I've bought support this so it is either uncommon or I've just been unlucky. Anyway, from what I've read Philips has used both the bluetooth method and the access point method on their WiFi products.
onraglanroad 11mo ago
I think this is the opening to a Korean horror movie...
dnautics 11mo ago
This is a very fun project with a corsi-rosenthal filter (a box fan taped to a bunch of normal house filters). To control the fan, you'll have to have some fun with a relay connected to MAINS voltage -- if you dare. The salon power relay hat is a reasonable solution (just remember to get voltage up/on for fail-dead). It's possible to squeeze everything inside of those cheap lasko fans you can get, too, if you want a challenge.
- gh02t 11mo ago
  Slightly easier/less mains electrical work required is to just use a smart plug of some sort, and there are multiple options you can put your own firmware on (e.g., Sonoff supports ESPHome). One caveat about this most people don't know is that most basic fans with a fully mechanical switch always order the speeds from High to Low, so that if you for instance want to turn it on to Low you have to briefly go through High (and Medium). This is on purpose, to briefly supply higher current to the motor for it to start spinning. Some fans might not like it if you start them from an external switch in low, especially larger ones with heavier blades. This also applies to the one in the article, but you can sequence things in software if you have full control of the fan speed, too.
  - regularfry 11mo ago
    What's odd is that while what you describe is true for fans with a rotary mechanical switch, where you have to physically turn the contacts through "High" to get to "Low", it's also very common for fans with independent speed buttons to put the "High" button next to "Off", with "Low" furthest away. I don't know if that's just a hold-over from rotary switches because people are used to the sequence, or if there's something else mechanical going on inside the switch unit which has the same effect. And on this occasion I'm not taking mine apart to find out.
zamalek 11mo ago
The digipot is vaguely similar to how a R2R ladder DAC works. There are two resistor values used: R and 2R. The "interesting part" of the circuit has bits x 2R resistors in parallel. One end of each resistor (let's call it input) is connected directly to the digital bit from the PWM sample. Then there is the series bits x R resistors. The output of each 2R resistor is connected in-between the two resistors that straddle its bit position. So: Out | R +-2R-bit0 R +-2R-bit1 ... R +-2R-bitN And that's it (apart from pull-up/down resistors)! Due to the way that resistors in series and parallel work, each input step in the ladder provides twice the voltage of the previous if powered: it's base 2 enshrined in a physical object. These are relatively uncommon because they are highly sensitive to the resistor (and trace) tolerance, but this circuit is my Euler's identity of electronics: it very literally bridges the digital and analog worlds.
- pxx 11mo ago
  I saw the diagram in the original blogpost, laughed, but after a bit of sketching it out I think we're both wrong. R/2R ladders are useful in DACs (and are really cool there) but don't look like they're used in digipot applications. It seems like actual digipot ICs use the "2^n discrete resistors" approach. The IC used in this project is a MCP4141 which explicitly states in section 5.1 of its datasheet that for 7-bit (8-bit) devices there are 128 (256) resistors in a string between the terminals. I'm a bit surprised this seems to be the best approach, but with IC manufacturing the joint problems of "a bunch of identical components" and "wiring it all up" are much less of a problem than if you were to wire this up by hand.
skopje 11mo ago
>> The PCB was ordered from JLCPCB, where I opted to have most of the components pre-soldered. very expensive, you are committed! :) you should have gone Full Giertz and added a badd little robot arm that turn the pot. esp32 are really nice: hundreds of code examples that do what you want without having to read too many pages. did you use ARDUINO IDE or idf.py SDK?
- announcer4614 11mo ago
  I was actually pleased with how cheap it ended up: less than $20 USD for the board + assembly + every component. I set ESPHome to use IDF under the hood, you can check out my full ESPHome config for this: https://git.ellis.codes/e/esphome-configs/src/branch/main/vornado.yaml https://git.ellis.codes/e/esphome-configs/src/branch/main/vo...
  - skopje 11mo ago
    interesting! i tried to order some assembled boards and was told $200+ (US) for only ~20 smd parts.
    - announcer4614 11mo ago
      I've noticed that some things can make the price suddenly skyrocket. Certain PCB specifications for one (though couldn't name anything in particular off hand). The one thing that caught me by surprise was that if I wanted to have JLCPCB solder the ESP32 for me the cost would jump by more than double, and the PCB would have to be physically larger. Something about their "Economic" vs. "Standard" PCB assembly where, for reasons I'm not clear on, the ESP32 could only be done under the latter. I opted to solder that component myself, of course.
- xobs 11mo ago
  My current record is $19 (including shipping!) for two assembled boards of https://github.com/xobs/soundoff https://github.com/xobs/soundoff which is a little device that shuts off 5V power to a USB-A port when it detects the PC it's connected to goes to sleep.
sailfast 11mo ago
I love this - but honestly I was expecting this to end with the fan not functioning due to wifi issues. :)
brcmthrowaway 11mo ago
How much does it cost to get a pcb made with all the components? I hate soldering but breadboards are limiting.
- 05 11mo ago
  As low as $10 if you all components are from JLCPCB's basic component library. For this board, more since there are some through-hole components and neither MCP4141 nor ESP32 (nor the buck modules used) are in the basic library.
  - brcmthrowaway 11mo ago
    What abt esp8266?
andsbf 11mo ago
Reading the comments here I feel like… I have found my people. I love toying with the esphome and homeassistant.
vswaroop04 11mo ago
I love these things toying with home assist
vrighter 11mo ago
I gave wifi to my AC, but went with a slightly different route. I used an ESP32 to reimplement its remote control and receiver. The ESP32 has dedicated hardware for implementing IR communications. I then recreated the remote control in the browser and had the system both send the right codes when pressed, and also receive any other valid signals (ex. if I used the actual remote) to sync the web ui with the ACs current state.

222 points by woolywonder 11mo ago

monerozcash 11mo ago

[flagged]

deleted 11mo ago

[deleted]

kylehotchkiss 11mo ago

Oh no don’t tell vornado this is possible and give them an enshittificafion pathway for their products

Eric_WVGG 11mo ago
IMO anything with unnecessary digital interfaces is already down the path. I have a Vornado fan that I would love to automate with a simple wifi-enabled plug, but due to the digital on/off/speed button, when you cut-off and restore power to the device, it stays off. If it had a dumb analog dial or switch, it would both be fine for normal use, and could be easily, cheaply made "smart." They do sell wifi-enabled fans; none of them are in a form factor that would fit in my window. I'm not even alone in this gripe, lots of other maniacs have done the hard work of conversions. Unfortunately I'm not confident enough in my soldering skills to try :\ https://www.reddit.com/r/electrical/comments/vaiskf/bypass_pushbutton_controls_on_vornado_fan_rewire/ https://www.reddit.com/r/electrical/comments/vaiskf/bypass_p...

hnuser123456 11mo ago

I actually like this idea. Makes more sense than smart fridges. Would be cool if this ESPHome thing worked with RP2350/Rpi Pico 2.

moffkalast 11mo ago
Could tie it to a thermometer and turn it on automatically on hot days. Very cool.
- madaxe_again 11mo ago
  Ideal for a beer fridge. Is today a beer in the sun day? If so, chill those bad boys. Otherwise, save the energy.
  - moffkalast 11mo ago
    Ah yes, buying tens of dollars worth of hardware to save cents worth of power. What being a hardware hobbyist is all about!
05 11mo ago
It's there, but you have to configure a custom platform due to politics between PIO and RPI. rp2040: board: rpipico2w framework: platform_version: https://github.com/maxgerhardt/platform-raspberrypi.git#develop version: dev esphome: platformio_options: build_flags: - -DPICO_VSYS_PIN=29 [0] https://github.com/esphome/feature-requests/issues/2837#issuecomment-2544595373 https://github.com/esphome/feature-requests/issues/2837#issu...

ttshaw1 11mo ago

I don't like the notion of doing speed control by putting a digipot in series with a motor. It worked because the fan happened to be low enough power but it doesn't seem like the author gave thought to the power handling capability of the digipot. If the fan happened to be beefier he's letting the smoke out with this design. Plus, this is more complicated than just doing PWM.

_ihaque 11mo ago
Based on the description of the wiring to the motor (24V, GND, POT1, POT2, NC), it doesn't sound like the original setup would have been drawing much power through the pot either -- there's probably something else on the other end of that wire that is doing modulation based on the sense resistance, and the motor is itself drawing power from the 24V line. So while it's true that there should be a check for the allowable limits on the digipot, I don't think it's actually being used to sink much power.
- 05 11mo ago
  > there's probably something else on the other end of that wire that is doing modulation based on the sense resistance And it would have been great if that arbitrary assumption had been tested by the OP and the results were documented in the article so that they wouldn't come off as somewhat clueless as to the limitations of their design.. oh well.
  - anamexis 11mo ago
    From the HN guidelines: > Be kind. Don't be snarky. Converse curiously; don't cross-examine. Edit out swipes. > Don't be curmudgeonly. Thoughtful criticism is fine, but please don't be rigidly or generically negative.
    - TylerE 11mo ago
      These passive aggressive posts are a far worse violation of the HN Guidelines than what they're in reply to almost all of the time - and this is no exception.

NegativeLatency 11mo ago

ESPHome and homeassistant have been really great, just like a nice breath of fresh air in a world of cloud saas stuff.

ssl-3 11mo ago
Home Assistant does great at tying all kinds of things together. People had a habit of leaving the basement lights on here. Now they turn themselves off after a timer expires, and also whenever nobody's home. Using HA and a cheap Shelly relay (chosen for form factor), I was able to do this while retaining the existing lighting circuits, light switch, and the lights themselves. It works perfectly, is completely local, and the end-user UI is completely natural. Toggle the same plain-Jane light switch that has always been there at the top of the basement stairs and the lights change state. (UI doesn't get more intuitive than that.) Or: Fans. This house has a good furnace and central aircon, but the ductwork doesn't really extend upstairs. By default, this makes the upstairs-parts very hot in the summer and cooler than I'd like in the winter -- even though it's nice downstairs during all seasons. I fixed that to my satisfaction by putting a fan on the landing that is controlled by an inexpensive smart switch, just to improve circulation. HA runs this show; the fan runs when the HVAC is doing something, and whenever people are home and it is either too hot or too cold upstairs (based on a temperature sensor). It's not a perfect solution, but it's kept the temperatures sane (and provided logging to prove it), it was cheap to implement, and it is cheap to run. I already had the parts kicking around; it just took software and time. (The best option for efficiency and comfort is probably installing mini-splits up there, but... sheesh, that's into the realm of orders-of-magnitude more expensive. Maybe some day.)
- NegativeLatency 11mo ago
  I'm curious how you used the shelly? They look neat but I'm not sure how people are wiring them into existing switches.
  - ssl-3 11mo ago
    Good question. I put the Shelly relay in a pre-existing junction box in the basement. Previously, this box worked like this: There were romex cables for power/neutral, lights, and the switch itself all inside of that box. The switch, located elsewhere, interrupted power to the lights. (This isn't necessarily the most-typical arrangement, but it's how it is in the house I've got.) Currently, the box works like this: We still have romex cables for power/neutral, lights, and the switch itself inside of that box. That part hasn't changed at all. But now the Shelly relay interrupts power to the lights. Thus, the lights are always controlled by software. And the light switch? That just provides an input that is acted upon by a software script. The script (which runs internally within the Shelly relay) only does 3 things: 1. If relay is on and switch toggles, turn relay off. 2. If relay is off and switch toggles, turn relay on. 3. If relay is turned on by any mechanism, start timer, and then turn off after timer expires. (Plus other useful timer mechanics like resets on additional toggling, but you get the idea.) --- It's easiest to think of a Shelly relay like a replacement for a light switch, but that's kind of a limiting way to think about it because that line of thought strongly implies that it should to be located where the switch is. And while it certainly can be installed that way, in practice it really doesn't have that limitation. For my unfinished basement, there's no neutral at the light switch location so using a regular smart switch didn't pan out. (I could have added a neutral but that would have meant using more parts and getting into some drywall and paint.) Instead, there's that neat (who am I kidding, it's a mess) junction box I that described, up on the ceiling where all of the things come together... So that's where I put the relay. Or: There's a box behind a light fixture (well, there "should" be anyway). Often, this box will have the same functions available inside that my junction box happened to have. Power, neutral, light(s), switch input. A relay can go there. But many houses do have neutral at the light switch location, so a relay can go there instead. Power/neutral feeds in, power for lights feeds out, with a switch (and/or relay!) in the middle. All in one accessible box on the wall. This matches the easy-to-think-of scenario. (IIRC all new homes are supposed to be this way in the US, but...) It's (usually!) just a matter of finding the right physical location in which to install the relay. (Note: None of this is intended to be an exhaustive list of variations. Things can and do get weird with household wiring, and regional variations of what "normal" means can vary quite tremendously.)

05 11mo ago

Why is there level conversion though if the digipot (MCP4141) is 2.7V to 5.5V? Personally I'd just use breadboard, it's just a 8 pin IC and a ESP module, for a one-off hack..

announcer4614 11mo ago
Hey, author here. There's a line in the digipot datasheet that says the voltage on the A/B/W pins must be within -0.3V to VDD + 0.3V. The fan's line for the wiper pin is 5V, which would fall well outside of that if I gave the digipot's VDD 3.3V.
- 05 11mo ago
  Thanks. Thinking more about that, might have been easier to just use 5V tolerant esp8266 :)
  - announcer4614 11mo ago
    Fair point, I hadn't thought to consider that aspect of the ESP8266. I mainly opted for the shiny new ESP32-C6 with the idea that I might one day set it up to use Thread instead of WiFi.

IvyMike 11mo ago

I've been toying with a variant of this project for my Honeywell home air filters. I have one in all my "big" rooms, and I like to keep them running at a low speed most of the day. But I also have time-of-day energy pricing, and it would be nice to automatically turn off (or at least slow) my air filters during the 5pm-8pm window. This project inspires me to at least look into the feasibility of adding that functionality myself.

NegativeLatency 11mo ago
Depending on your air filter you might be able to just use a smart plug, I went down a similar route this summer before realizing that mine would remember their power state and settings when powered off. So now I just have them plugged into a few smart plugs with automations in homeassistant
- reaperducer 11mo ago
  Why not just use a dumb timer plug from a hardware store? Ten bucks, and completely hacker-proof: https://www.acehardware.com/departments/lighting-and-electrical/timers-and-lighting-controls/timers/3001316 https://www.acehardware.com/departments/lighting-and-electri... $16 if you need a remote control: https://www.acehardware.com/departments/lighting-and-electrical/timers-and-lighting-controls/timers/3001320 https://www.acehardware.com/departments/lighting-and-electri... Or $17 if you want to get all digital and fancy: https://www.acehardware.com/p/3001323 https://www.acehardware.com/p/3001323
  - NegativeLatency 11mo ago
    Sure those work, I've tried them before, but I find them more fiddly and less fun to program than homeassistant. Also I can easily turn them on or off from my phone which is nice if I'm feeling lazy.
- XorNot 11mo ago
  This is what I do with my dehumidifiers. It's been working so well I was actually surprised one night when the dehumidifier in the bedroom turned itself on from the automation (which I have set to do after dark if humidity is higher then 70%). It had been within tolerance for ages and I just hadn't had to even think about it.

uoaei 11mo ago

I love upgrading simple home appliances with homebrew smarts using ESPHome so that they retain their original interface. I've mostly done lights that are still correctly switched at the original wall switches but up next is my fan and toaster oven! Then to tackle the thermostats.

supportengineer 11mo ago

The next step would be to monetize it with ads, and put some of the features behind a monthly subscription. Premium oscillation package, only $9.99 a month.

alexchantavy 11mo ago
Need $150 a month to add SSO though
- bigiain 11mo ago
  Single Sweat Off is an Enterprise Only requirement.
iambateman 11mo ago
$9.99 is for a single user. Extra users cost $14.99 each sold in packs of 5 with a three year minimum contract.
nrhrjrjrjtntbt 11mo ago
Premium oscillation package. We still talking fans? Or only fans?
- ninju 11mo ago
  OnlyFans...I see what you did there :-)
celloductor 11mo ago
what abut adding a gps in there, you can then use it in different rooms only if you pay a $5 multiple location unlocking fee

jonhohle 11mo ago

This is amazingly cool. Did you consider putting a rotary encoder on the PCB to maintain local control over the speed?

announcer4614 11mo ago
That's exactly what I did :) and a convenient thing I realised afterwards is that the push-button function of the rotary encoder gives me the ability to turn the thing on and off with my foot!
- jonhohle 11mo ago
  (Facepalm) I looked at the pictures and skimmed, missing the encoder part. Awesome!

mihaaly 11mo ago

I purchased a Phillips fan in a shopping spree. It was hot outside, needed something, did not pay much attention beyond that it worked and was not noisy. At home my eyebrows went halfway on my forehead seeing that there is a remote and the remote is supposed to be my mobile! Need to download the app for it, connect the fan to the Wifi, but it also had bluetooth for some reason. No way Jose! Yet, it was so incredibly stupid like 4K zoom camera in a hammer that I had to try. Carefully. Data collection notice in the app shop is not promising, not at all. Location data, ID, I do not remember in full but perhaps contacts too? Unsure, but a lot. Anyway, will not enable access to most, airplane mode on, no bluetooth device in sight, so went ahead and installed the app, router disconnected from the internet, then run it. First thing: refusing access to location. App: sorry, you cannot use me if I cannot access your location, network, and my mothership. And it stops. Big laugh, delete the whole thing. Leaving feedback for other customers about this incredibly stupid intrusion. Then I got answer from Phillips! Something along the line: "This is for the best interest of our customers, we need your precise location so we can share personalized pollen and climate data and whatnot, we absolutely must insist this!" For a fan! Meanwhile the fan has physical buttons on it, can adjust speed, timer, and the cycle. Not completely useless. However some buttons need two press to register the action once. Beeps twice, does thing once. Likely some interference with The App, need to make sure that I am in the same room with the fan with a warning press and then the real press, or whothef knows what was in the head of these guys when they put this piece of thing together!? But really, are they nuts? Ruining use along pollen data?! Are we already living the movie Idiocracy when it is about the Phillips product design department?! Did they loose all sense with reality? I am sure they already pushing through some new AI function for this very fan and are sad that mine cannot connect to the mother ship through satellite or something just so the update can be pushed to it learning my breath patterns for optimal fan speed. They are nuts! They are nuts!

tzs 11mo ago
> Need to download the app for it, connect the fan to the Wifi, but it also had bluetooth for some reason. Bluetooth could be there for initial setup. To connect the fan to WiFi you have to somehow get the WiFi credentials to the fan. There are a few ways to do that. One of the most common is for the device when it has not yet been set up to make itself available over Bluetooth. The app can then connect to it and give it the WiFi credentials. Another common way is for the device to create its own WiFi network with a name that the app can somehow recognize. The app can then find that network, connect to it, and use it to talk to the device. I don't think this is as popular as the Bluetooth method, probably because it used to require that the user go to their network settings and connect to the device's WiFi network. Plus, when they are connected to the device they are not connected to their "real" WiFi which could disrupt other apps. However, newer Apple and Android mobile operating systems provide ways for applications to change the network connection in the background or with minimal interaction, which makes this method more friendly so maybe it will become more popular. There also are supposedly some IoT devices that use WPS (WiFi Protected Setup), where you bring the device near your router, press the WPS button on the router, then press the WPS button on the device, and magic happens to add the devide to your network. I've never actually had any device I've bought support this so it is either uncommon or I've just been unlucky. Anyway, from what I've read Philips has used both the bluetooth method and the access point method on their WiFi products.

onraglanroad 11mo ago

I think this is the opening to a Korean horror movie...

dnautics 11mo ago

This is a very fun project with a corsi-rosenthal filter (a box fan taped to a bunch of normal house filters). To control the fan, you'll have to have some fun with a relay connected to MAINS voltage -- if you dare. The salon power relay hat is a reasonable solution (just remember to get voltage up/on for fail-dead). It's possible to squeeze everything inside of those cheap lasko fans you can get, too, if you want a challenge.

gh02t 11mo ago
Slightly easier/less mains electrical work required is to just use a smart plug of some sort, and there are multiple options you can put your own firmware on (e.g., Sonoff supports ESPHome). One caveat about this most people don't know is that most basic fans with a fully mechanical switch always order the speeds from High to Low, so that if you for instance want to turn it on to Low you have to briefly go through High (and Medium). This is on purpose, to briefly supply higher current to the motor for it to start spinning. Some fans might not like it if you start them from an external switch in low, especially larger ones with heavier blades. This also applies to the one in the article, but you can sequence things in software if you have full control of the fan speed, too.
- regularfry 11mo ago
  What's odd is that while what you describe is true for fans with a rotary mechanical switch, where you have to physically turn the contacts through "High" to get to "Low", it's also very common for fans with independent speed buttons to put the "High" button next to "Off", with "Low" furthest away. I don't know if that's just a hold-over from rotary switches because people are used to the sequence, or if there's something else mechanical going on inside the switch unit which has the same effect. And on this occasion I'm not taking mine apart to find out.

zamalek 11mo ago

The digipot is vaguely similar to how a R2R ladder DAC works. There are two resistor values used: R and 2R. The "interesting part" of the circuit has bits x 2R resistors in parallel. One end of each resistor (let's call it input) is connected directly to the digital bit from the PWM sample. Then there is the series bits x R resistors. The output of each 2R resistor is connected in-between the two resistors that straddle its bit position. So: Out | R +-2R-bit0 R +-2R-bit1 ... R +-2R-bitN And that's it (apart from pull-up/down resistors)! Due to the way that resistors in series and parallel work, each input step in the ladder provides twice the voltage of the previous if powered: it's base 2 enshrined in a physical object. These are relatively uncommon because they are highly sensitive to the resistor (and trace) tolerance, but this circuit is my Euler's identity of electronics: it very literally bridges the digital and analog worlds.

pxx 11mo ago
I saw the diagram in the original blogpost, laughed, but after a bit of sketching it out I think we're both wrong. R/2R ladders are useful in DACs (and are really cool there) but don't look like they're used in digipot applications. It seems like actual digipot ICs use the "2^n discrete resistors" approach. The IC used in this project is a MCP4141 which explicitly states in section 5.1 of its datasheet that for 7-bit (8-bit) devices there are 128 (256) resistors in a string between the terminals. I'm a bit surprised this seems to be the best approach, but with IC manufacturing the joint problems of "a bunch of identical components" and "wiring it all up" are much less of a problem than if you were to wire this up by hand.

skopje 11mo ago

>> The PCB was ordered from JLCPCB, where I opted to have most of the components pre-soldered. very expensive, you are committed! :) you should have gone Full Giertz and added a badd little robot arm that turn the pot. esp32 are really nice: hundreds of code examples that do what you want without having to read too many pages. did you use ARDUINO IDE or idf.py SDK?

announcer4614 11mo ago
I was actually pleased with how cheap it ended up: less than $20 USD for the board + assembly + every component. I set ESPHome to use IDF under the hood, you can check out my full ESPHome config for this: https://git.ellis.codes/e/esphome-configs/src/branch/main/vornado.yaml https://git.ellis.codes/e/esphome-configs/src/branch/main/vo...
- skopje 11mo ago
  interesting! i tried to order some assembled boards and was told $200+ (US) for only ~20 smd parts.
  - announcer4614 11mo ago
    I've noticed that some things can make the price suddenly skyrocket. Certain PCB specifications for one (though couldn't name anything in particular off hand). The one thing that caught me by surprise was that if I wanted to have JLCPCB solder the ESP32 for me the cost would jump by more than double, and the PCB would have to be physically larger. Something about their "Economic" vs. "Standard" PCB assembly where, for reasons I'm not clear on, the ESP32 could only be done under the latter. I opted to solder that component myself, of course.
xobs 11mo ago
My current record is $19 (including shipping!) for two assembled boards of https://github.com/xobs/soundoff https://github.com/xobs/soundoff which is a little device that shuts off 5V power to a USB-A port when it detects the PC it's connected to goes to sleep.

sailfast 11mo ago

I love this - but honestly I was expecting this to end with the fan not functioning due to wifi issues. :)

brcmthrowaway 11mo ago

How much does it cost to get a pcb made with all the components? I hate soldering but breadboards are limiting.

05 11mo ago
As low as $10 if you all components are from JLCPCB's basic component library. For this board, more since there are some through-hole components and neither MCP4141 nor ESP32 (nor the buck modules used) are in the basic library.
- brcmthrowaway 11mo ago
  What abt esp8266?

andsbf 11mo ago

Reading the comments here I feel like… I have found my people. I love toying with the esphome and homeassistant.

vswaroop04 11mo ago

I love these things toying with home assist

vrighter 11mo ago

I gave wifi to my AC, but went with a slightly different route. I used an ESP32 to reimplement its remote control and receiver. The ESP32 has dedicated hardware for implementing IR communications. I then recreated the remote control in the browser and had the system both send the right codes when pressed, and also receive any other valid signals (ex. if I used the actual remote) to sync the web ui with the ACs current state.