10 ms·

How we built a Smart Office system based on Raspberry Pi

200 points by dragonbonheur 10y ago

detaro 10y ago
Good to see in a DIY-solution: > The light control set up is fail-safe. If something with the RPi goes terribly wrong, we could still operate the lights in the “classic” analog way. (I wish they'd explained how they do it, but I assume they use latching relays to switch the actual lights, so RPis and light switches can work in parallel) Using the chrome debugging protocol for the remote screens is also quite clever.
- existencebox 10y ago
  I have Rpis controlling my various plant-grow-lamps around the house; the relays they switch are set to fail-open so if they fall over I can go back to manual control; so you probably assume correctly. Now if the relays themselves get sad I'd probably be in for a bad time but fixing that seems like a reduction problem? (I speak as someone clueless about actual EE beyond treating it like legos)
  - jasoncchild 10y ago
    Yeah normally open relays with standard switches wired in parallel.
    - janci 10y ago
      Just don't connect one phase to the relay and different phase to the switch.
  - analog31 10y ago
    I don't know what kind of relays you're using, but most relays tend to fail in a closed position, so it's worth considering what happens if a light is turned on continuously. Also, hardware or software failure in the RPi could turn on all of the lights in your house, e.g., if the same software running on every unit encounters a bug.
    - kamil_gorski 10y ago
      And for those cases I decided to place wall switches in parallel. As automation fails you can still operate all lights with classic, wall switch, way. Also, solution for jamming relays are SSRs. In practice there were issues only with two biggest light zones with multiple lamps switched at the same time.
      - analog31 10y ago
        I've had SSR's stuck shut too.
  - beagle3 10y ago
    Most relays are rated for a "number of switches", usually in the few hundreds-of-thousands for both mechanical and SSDs. If you switch twice a day (on/off), you've got a few hundred years. Note, however, that switching voltages/currents higher than rated will likely shorten the life of your relay.
- aexaey 10y ago
  From what I understood looking at the photos in the article, "relays" are some fancy-looking external box. It is quite possible that those are "pulse relays", i.e. RPi sends a short voltage pulse to switch relay on, then another short pulse over the same wire to switch off. From there all you need is two (or more) diodes to handle multiple pulse inputs. Some pulse relays even have diodes built-in (i.e. can handle multiple inputs from the get-go). You can easily spot this sort of installation - wall-mounted light switches only go one way, and return to original position as soon as let go. And each press changes on/off state - sort of how Caps Lock works.
- g_hajdukiewicz 10y ago
  Hey! I was happy to be designing this beauty (and using it everyday in our office). It's nothing more than just a "stair switch" configuration, where one of the manual switches was substituted with a relay. So we have all SPDT manual switches on the walls, and SPDT relays connected with them in our control cabinet. Every switch/relay can change state of the receiver (in this case a LED lamp) at any time. So even if relays or RPIs fail we can still be using manual switches. More info here https://goo.gl/sJw9F1 https://goo.gl/sJw9F1 .
jasoncchild 10y ago
I'm surprised all they found were PLC based solutions. I worked in lighting and building controls for years and most products used embedded systems and not PLCs.
- g_hajdukiewicz 10y ago
  Hey, you're totally right. Actually we would normally use some embedded solution for that (preferably STM32 or ESP8266 if wireless was needed), however, in this case we were focusing on designing it in a way so that it's easy to maintain by web-development agency, which we are. Not everyone here knows how to change and flash low-level code into a uC but almost everyone would be able to fix a bug in python code on the RPi :)
revelation 10y ago
That's like saying "How we built a Smart Office system based on Electricity", the RPi is just any old single board computer here with some GPIOs. In any case, I sure hope they have mounted their SD cards as read-only, because otherwise they might find their keycard system not working one early morning in approximately a year or 2-3 random power off events. Theres a reason for these PLC systems after all.
- rcaught 10y ago
  Are you suggesting that they will reach the flash memory's write cycle limit within a year? Or something else here? Also, I would not have thought that random power off events would affect modern file systems as poorly as you're suggesting. Interesting thoughts though.
  - analog31 10y ago
    There's something else. The RPi is prone to failure if it's writing to the SD card when power goes down. Articles that I've read suggest moving most of the RPi's files to some other form of storage, for instance: https://learn.adafruit.com/external-drive-as-raspberry-pi-root/overview https://learn.adafruit.com/external-drive-as-raspberry-pi-ro... I've thought about the idea of having some super-capacitor based temporary power storage, and an interrupt that triggers a graceful shutdown if the power input goes down. I think it could be done with fairly basic circuitry.
    - Dylan16807 10y ago
      A small lithium ion with a sub-dollar charger/regulator is probably cheaper than a supercap.
    - shabble 10y ago
      such things exist (such as the pico from http://pimodules.com/ http://pimodules.com/) but I've had nothing but grief from its firmware using v1 and v2. There appears to be a new version, and I suppose it might be better now. For most <1 day outages, a simple USB power-bank with passthrough capability (output whilst also possibly charging) will happily keep the pi going, but without some frankenbodging there's no 'power lost' signal that the pi can sense. I've idly toyed with the idea of a phototransistor on the powerbank status LED and an attiny or something. Now that I think about it, there was someone trying to make a supercap idea, but I don't think it went anywhere: https://www.indiegogo.com/projects/juice4halt-supercapacitor-ups-for-raspberry-pi#/ https://www.indiegogo.com/projects/juice4halt-supercapacitor...
amelius 10y ago
We've seen projects like these in DIY magazines since the 70s. But Nest took off, and thus so could this.
kimburgess 10y ago
Yay, this is my world! Looks like a super nice homebrew solution. I don't think I've ever used or worked on a project with PLC's handling any sort of core logic though. Sure they'll occasionally run small components of simple edge systems (HVAC, lift motor control, physical access etc) but the overwhelming majority of systems are built with a network of embedded controllers. Any systems rolling out today will (or at least should) then combine this with some server side backend for analytics and shifting interaction logic away from the the edge systems to somewhere it's a little easier to change and adapt to the needs of the building. There's some pretty established, older players (Crestron, AMX et al) that make full programmable solutions, but by all modern standards their development tools are atrocious - you'd need to be a complete and utter masochist to want to enter that world today. The good thing about this is a bunch of amazing people building well designed, open source and non-proprietary solutions to make this world suck less. My two favourites are http://nodel.io/ http://nodel.io/, which runs a fully distributed architecture (and can even have the nodes running of RPi's) and http://www.acaprojects.com/ http://www.acaprojects.com/ which is a keeps all the system logic server side.
- jasoncchild 10y ago
  Yeah, even stuff like Niagra is a pain. Most solutions are configurable more so than programmable (in the scripting sense). I've done a fair amount of modbus and bacnet with "standard" systems and more pi-style systems and agree that for a developer-minded user it can be like gazing into the mouth of madness to work with.
- kamil_gorski 10y ago
  We were aiming into easy customizability at high level code and I couldn't find any commercial system meeting this requirements. I'm very much into open-source, so thank you for those two solutions. I haven't seen it before.
ubercow 10y ago
Anyone know what boards they are using for their relay controllers?
- g_hajdukiewicz 10y ago
  We designed our own, simple ones having MCP23017 (https://goo.gl/S4i9Gw https://goo.gl/S4i9Gw) as the GPIO expanders and some popular optocouplers to provide proper isolation level. I can't remember which exact part was chosen for the isolator, but this one should work like a charm https://goo.gl/GS6twt https://goo.gl/GS6twt.
joshu 10y ago
Anyone know what hardware they are actually using other than the RPis?
- kamil_gorski 10y ago
  Relay modules from finder, custom pcb modules with current outputs for switching relays and optoisolators for voltage detecion, some custom expansion module for all signals interconnection. I will prepare some appendix to the blog-post with more technical data.
  - tga 10y ago
    I'd love to see more details on that. The RPi is the easy choice for putting together a DIY system at home, but finding good and affordable remote I/O modules to run the show has not been that straightforward.
chj 10y ago
Last time I tried, webkit for RPi leaks memory after playing audio for a few hours. It would be great to have a follow up post after the system is in production use for a while.
- tuukkah 10y ago
  "Now, after a year from launching our smart office system based on 7 Raspberry Pis we know there is nothing to be afraid of!"
Loic 10y ago
A DIY-solution is nice (and as engineers something really fun to do) but they will have to maintain it in the future and this is not necessarily "future proof". They would have simply put some KNX[0] compatible components in the system, they would have had control of everything using an open standard. They could have connect light, security cams, door locks, the power plugs, etc... and because this is a standard, the day they move out of the office, they will be able to resell the system to the next users. [0]: https://knx.org https://knx.org
- eveningcoffee 10y ago
  KNX would be definitely a choice but you have to be careful and shop around as many KNX manufactures are known to be incredibly greedy. The situation has improved a lot in recent years though. Also the term open is very relative here (you have to pay a fee (1000 euro + VAT last time I checked) to access the standard, naturally there are no redistribution rights, KNX certification process is order of magnitude more expensive. You need a closed source configuration software to be able to configure the devices. Runs only on Windows (XP did it last time but things may have been changed). A single licence costs 1000 euro + VAT, unless you use limited version that works up to 20 devices and costs 100 euro + VAT (in many small cases that would be enough as the limitation is project based). PS. It is rather an attempt to put things into a contexts than a criticism. Minimum setup: 1) KNX power supply (provides power for the KNX bus), 2) KNX actuator (relay or dimmer or special (say LED stripe)), 3) KNX switch (or an input device (can use standard wall spring switches)), 4) KNX bus connector for programming (USB tongle, KNX/IP router, there are many options), 5) KNX configuration software, 6) Windows machine (VM works too). This setup allows to map the actuator and switch in the configuration software and upload the configuration into the devices. Please also note that encrypted communication between KNX devices is commonly not supported (but so is it also for a simple pulse signal from the wall switch to the relay).
  - kamil_gorski 10y ago
    Exactly. Price level of our system is incomparable with same solution based on KNX. Future modifications and changes will be easy even with support discontinuation from our side. Every part of the system is modular - you can pull out RPi with custom modules and place any PLC instead.
jcoffland 10y ago
You could do most of this with the X10 system.
- mountaineer22 10y ago
  Yes, and a TRS-80.
  - jcoffland 10y ago
    I don't think the Trash 80 came with network over power lines or wireless communication.
    - Sanddancer 10y ago
      Radio Shack had a control module you plugged into the cassette port that interfaced with the X10 bus. http://www.trs-80.org/plug-n-power/ http://www.trs-80.org/plug-n-power/
      - jcoffland 10y ago
        Now that's retro.
cerved 10y ago
Fun to see someone do this with the pi. I wonder how they handle security. Especially since it also controls access to the facility. Also, would be pretty funny if the RPis went all Hall one day.
- kamil_gorski 10y ago
  RPi is only accessible in separate local network. Doors also has regular locks which are used after working hours. In case of sytem failure almost all parts has alternative working conditions: lights can be controlled with wall switches, rfid lock can be programmed separatly, etc.
rem1313 10y ago
Some more technical implementation info - hardware, software and how it is all connected would be much appreciated!
- g_hajdukiewicz 10y ago
  Thanks for asking! I can explain you how the lighting unit works since I was taking part in designing it (better than nothing :) ). Since we didn't have enough GPIOs on the Raspberry which is controlling the lights, we used a GPIO expanders (MCP23017 https://goo.gl/S4i9Gw https://goo.gl/S4i9Gw). RPi sends commands over I2C interface to switch their outputs on and off. MCPs outputs are driving optocouplers (on the same PCBs designed by us) to provide a proper level of isolation. Then the optocouplers' outputs drive the relays working in a "stair case" configuration with analog switches on the walls (see a my comment above and here https://goo.gl/sJw9F1 https://goo.gl/sJw9F1). All the "low-level" software is written in python using ready to go libraries and exposing API to a web-app which is basically a user interface for the system. If you need more details, just shoot!
  - SpikedCola 10y ago
    Love your use of wire duct to keep things organized, and small attention to detail like ferrules on each wire going into the terminal blocks. To my eyes this shows really you care about what you build. Nice job!
    - g_hajdukiewicz 10y ago
      Many thanks! It's always good to design your system like that. The same with software :) Makes it easier to maintain.

200 points by dragonbonheur 10y ago

Good to see in a DIY-solution: > The light control set up is fail-safe. If something with the RPi goes terribly wrong, we could still operate the lights in the “classic” analog way. (I wish they'd explained how they do it, but I assume they use latching relays to switch the actual lights, so RPis and light switches can work in parallel) Using the chrome debugging protocol for the remote screens is also quite clever.

existencebox 10y ago
I have Rpis controlling my various plant-grow-lamps around the house; the relays they switch are set to fail-open so if they fall over I can go back to manual control; so you probably assume correctly. Now if the relays themselves get sad I'd probably be in for a bad time but fixing that seems like a reduction problem? (I speak as someone clueless about actual EE beyond treating it like legos)
- jasoncchild 10y ago
  Yeah normally open relays with standard switches wired in parallel.
  - janci 10y ago
    Just don't connect one phase to the relay and different phase to the switch.
- analog31 10y ago
  I don't know what kind of relays you're using, but most relays tend to fail in a closed position, so it's worth considering what happens if a light is turned on continuously. Also, hardware or software failure in the RPi could turn on all of the lights in your house, e.g., if the same software running on every unit encounters a bug.
  - kamil_gorski 10y ago
    And for those cases I decided to place wall switches in parallel. As automation fails you can still operate all lights with classic, wall switch, way. Also, solution for jamming relays are SSRs. In practice there were issues only with two biggest light zones with multiple lamps switched at the same time.
    - analog31 10y ago
      I've had SSR's stuck shut too.
- beagle3 10y ago
  Most relays are rated for a "number of switches", usually in the few hundreds-of-thousands for both mechanical and SSDs. If you switch twice a day (on/off), you've got a few hundred years. Note, however, that switching voltages/currents higher than rated will likely shorten the life of your relay.
aexaey 10y ago
From what I understood looking at the photos in the article, "relays" are some fancy-looking external box. It is quite possible that those are "pulse relays", i.e. RPi sends a short voltage pulse to switch relay on, then another short pulse over the same wire to switch off. From there all you need is two (or more) diodes to handle multiple pulse inputs. Some pulse relays even have diodes built-in (i.e. can handle multiple inputs from the get-go). You can easily spot this sort of installation - wall-mounted light switches only go one way, and return to original position as soon as let go. And each press changes on/off state - sort of how Caps Lock works.
g_hajdukiewicz 10y ago
Hey! I was happy to be designing this beauty (and using it everyday in our office). It's nothing more than just a "stair switch" configuration, where one of the manual switches was substituted with a relay. So we have all SPDT manual switches on the walls, and SPDT relays connected with them in our control cabinet. Every switch/relay can change state of the receiver (in this case a LED lamp) at any time. So even if relays or RPIs fail we can still be using manual switches. More info here https://goo.gl/sJw9F1 https://goo.gl/sJw9F1 .

jasoncchild 10y ago

I'm surprised all they found were PLC based solutions. I worked in lighting and building controls for years and most products used embedded systems and not PLCs.

g_hajdukiewicz 10y ago
Hey, you're totally right. Actually we would normally use some embedded solution for that (preferably STM32 or ESP8266 if wireless was needed), however, in this case we were focusing on designing it in a way so that it's easy to maintain by web-development agency, which we are. Not everyone here knows how to change and flash low-level code into a uC but almost everyone would be able to fix a bug in python code on the RPi :)

revelation 10y ago

That's like saying "How we built a Smart Office system based on Electricity", the RPi is just any old single board computer here with some GPIOs. In any case, I sure hope they have mounted their SD cards as read-only, because otherwise they might find their keycard system not working one early morning in approximately a year or 2-3 random power off events. Theres a reason for these PLC systems after all.

rcaught 10y ago
Are you suggesting that they will reach the flash memory's write cycle limit within a year? Or something else here? Also, I would not have thought that random power off events would affect modern file systems as poorly as you're suggesting. Interesting thoughts though.
- analog31 10y ago
  There's something else. The RPi is prone to failure if it's writing to the SD card when power goes down. Articles that I've read suggest moving most of the RPi's files to some other form of storage, for instance: https://learn.adafruit.com/external-drive-as-raspberry-pi-root/overview https://learn.adafruit.com/external-drive-as-raspberry-pi-ro... I've thought about the idea of having some super-capacitor based temporary power storage, and an interrupt that triggers a graceful shutdown if the power input goes down. I think it could be done with fairly basic circuitry.
  - Dylan16807 10y ago
    A small lithium ion with a sub-dollar charger/regulator is probably cheaper than a supercap.
  - shabble 10y ago
    such things exist (such as the pico from http://pimodules.com/ http://pimodules.com/) but I've had nothing but grief from its firmware using v1 and v2. There appears to be a new version, and I suppose it might be better now. For most <1 day outages, a simple USB power-bank with passthrough capability (output whilst also possibly charging) will happily keep the pi going, but without some frankenbodging there's no 'power lost' signal that the pi can sense. I've idly toyed with the idea of a phototransistor on the powerbank status LED and an attiny or something. Now that I think about it, there was someone trying to make a supercap idea, but I don't think it went anywhere: https://www.indiegogo.com/projects/juice4halt-supercapacitor-ups-for-raspberry-pi#/ https://www.indiegogo.com/projects/juice4halt-supercapacitor...

amelius 10y ago

We've seen projects like these in DIY magazines since the 70s. But Nest took off, and thus so could this.

kimburgess 10y ago

Yay, this is my world! Looks like a super nice homebrew solution. I don't think I've ever used or worked on a project with PLC's handling any sort of core logic though. Sure they'll occasionally run small components of simple edge systems (HVAC, lift motor control, physical access etc) but the overwhelming majority of systems are built with a network of embedded controllers. Any systems rolling out today will (or at least should) then combine this with some server side backend for analytics and shifting interaction logic away from the the edge systems to somewhere it's a little easier to change and adapt to the needs of the building. There's some pretty established, older players (Crestron, AMX et al) that make full programmable solutions, but by all modern standards their development tools are atrocious - you'd need to be a complete and utter masochist to want to enter that world today. The good thing about this is a bunch of amazing people building well designed, open source and non-proprietary solutions to make this world suck less. My two favourites are http://nodel.io/ http://nodel.io/, which runs a fully distributed architecture (and can even have the nodes running of RPi's) and http://www.acaprojects.com/ http://www.acaprojects.com/ which is a keeps all the system logic server side.

jasoncchild 10y ago
Yeah, even stuff like Niagra is a pain. Most solutions are configurable more so than programmable (in the scripting sense). I've done a fair amount of modbus and bacnet with "standard" systems and more pi-style systems and agree that for a developer-minded user it can be like gazing into the mouth of madness to work with.
kamil_gorski 10y ago
We were aiming into easy customizability at high level code and I couldn't find any commercial system meeting this requirements. I'm very much into open-source, so thank you for those two solutions. I haven't seen it before.

ubercow 10y ago

Anyone know what boards they are using for their relay controllers?

g_hajdukiewicz 10y ago
We designed our own, simple ones having MCP23017 (https://goo.gl/S4i9Gw https://goo.gl/S4i9Gw) as the GPIO expanders and some popular optocouplers to provide proper isolation level. I can't remember which exact part was chosen for the isolator, but this one should work like a charm https://goo.gl/GS6twt https://goo.gl/GS6twt.

joshu 10y ago

Anyone know what hardware they are actually using other than the RPis?

kamil_gorski 10y ago
Relay modules from finder, custom pcb modules with current outputs for switching relays and optoisolators for voltage detecion, some custom expansion module for all signals interconnection. I will prepare some appendix to the blog-post with more technical data.
- tga 10y ago
  I'd love to see more details on that. The RPi is the easy choice for putting together a DIY system at home, but finding good and affordable remote I/O modules to run the show has not been that straightforward.

chj 10y ago

Last time I tried, webkit for RPi leaks memory after playing audio for a few hours. It would be great to have a follow up post after the system is in production use for a while.

tuukkah 10y ago
"Now, after a year from launching our smart office system based on 7 Raspberry Pis we know there is nothing to be afraid of!"

Loic 10y ago

A DIY-solution is nice (and as engineers something really fun to do) but they will have to maintain it in the future and this is not necessarily "future proof". They would have simply put some KNX[0] compatible components in the system, they would have had control of everything using an open standard. They could have connect light, security cams, door locks, the power plugs, etc... and because this is a standard, the day they move out of the office, they will be able to resell the system to the next users. [0]: https://knx.org https://knx.org

eveningcoffee 10y ago
KNX would be definitely a choice but you have to be careful and shop around as many KNX manufactures are known to be incredibly greedy. The situation has improved a lot in recent years though. Also the term open is very relative here (you have to pay a fee (1000 euro + VAT last time I checked) to access the standard, naturally there are no redistribution rights, KNX certification process is order of magnitude more expensive. You need a closed source configuration software to be able to configure the devices. Runs only on Windows (XP did it last time but things may have been changed). A single licence costs 1000 euro + VAT, unless you use limited version that works up to 20 devices and costs 100 euro + VAT (in many small cases that would be enough as the limitation is project based). PS. It is rather an attempt to put things into a contexts than a criticism. Minimum setup: 1) KNX power supply (provides power for the KNX bus), 2) KNX actuator (relay or dimmer or special (say LED stripe)), 3) KNX switch (or an input device (can use standard wall spring switches)), 4) KNX bus connector for programming (USB tongle, KNX/IP router, there are many options), 5) KNX configuration software, 6) Windows machine (VM works too). This setup allows to map the actuator and switch in the configuration software and upload the configuration into the devices. Please also note that encrypted communication between KNX devices is commonly not supported (but so is it also for a simple pulse signal from the wall switch to the relay).
- kamil_gorski 10y ago
  Exactly. Price level of our system is incomparable with same solution based on KNX. Future modifications and changes will be easy even with support discontinuation from our side. Every part of the system is modular - you can pull out RPi with custom modules and place any PLC instead.

jcoffland 10y ago

You could do most of this with the X10 system.

mountaineer22 10y ago
Yes, and a TRS-80.
- jcoffland 10y ago
  I don't think the Trash 80 came with network over power lines or wireless communication.
  - Sanddancer 10y ago
    Radio Shack had a control module you plugged into the cassette port that interfaced with the X10 bus. http://www.trs-80.org/plug-n-power/ http://www.trs-80.org/plug-n-power/
    - jcoffland 10y ago
      Now that's retro.

cerved 10y ago

Fun to see someone do this with the pi. I wonder how they handle security. Especially since it also controls access to the facility. Also, would be pretty funny if the RPis went all Hall one day.

kamil_gorski 10y ago
RPi is only accessible in separate local network. Doors also has regular locks which are used after working hours. In case of sytem failure almost all parts has alternative working conditions: lights can be controlled with wall switches, rfid lock can be programmed separatly, etc.

rem1313 10y ago

Some more technical implementation info - hardware, software and how it is all connected would be much appreciated!

g_hajdukiewicz 10y ago
Thanks for asking! I can explain you how the lighting unit works since I was taking part in designing it (better than nothing :) ). Since we didn't have enough GPIOs on the Raspberry which is controlling the lights, we used a GPIO expanders (MCP23017 https://goo.gl/S4i9Gw https://goo.gl/S4i9Gw). RPi sends commands over I2C interface to switch their outputs on and off. MCPs outputs are driving optocouplers (on the same PCBs designed by us) to provide a proper level of isolation. Then the optocouplers' outputs drive the relays working in a "stair case" configuration with analog switches on the walls (see a my comment above and here https://goo.gl/sJw9F1 https://goo.gl/sJw9F1). All the "low-level" software is written in python using ready to go libraries and exposing API to a web-app which is basically a user interface for the system. If you need more details, just shoot!
- SpikedCola 10y ago
  Love your use of wire duct to keep things organized, and small attention to detail like ferrules on each wire going into the terminal blocks. To my eyes this shows really you care about what you build. Nice job!
  - g_hajdukiewicz 10y ago
    Many thanks! It's always good to design your system like that. The same with software :) Makes it easier to maintain.