5 ms·

If you want to monitor things around you, and you have an SDR dongle set up, rtl_433 is handy. I have a Pi 3 running it to graph temperature and humidity readin

If you want to monitor things around you, and you have an SDR dongle set up, rtl_433 is handy. I have a Pi 3 running it to graph temperature and humidity readings from a couple of remote-reading sensors, plus barometric pressure from a Sense Hat and voltage, load, and battery readings from my UPS. It will display selected readings on the LED display, but I mostly just let mrtg/rrdtool do its thing. https://github.com/merbanan/rtl_433 https://github.com/merbanan/rtl_433

hdjjhhvvhga 4y ago
My first thought was, "Why would I need SDR to read temperature/humidity from sensors", then I realized these are more like wireless weather stations. Out of curiosity: why did you decide to purchase ready solutions instead of rolling your own using ESP32 for a fraction of the price?
- margalabargala 4y ago
  Not the person you replied to, but someone who did the same thing: Most of the things inside my house are ESP32 or zigbee things I put together myself. Things that go outdoors, though, I'm much more likely to purchase an off-the-shelf solution for longevity's sake. Especially if the whole point of the item is to be rained/snowed on, be left in direct sunlight, and so forth.
  - sgt 4y ago
    You can always build a tiny little house for your outside ESP and leave it outside.
    - tlavoie 4y ago
      Yeah, mine's under a deck, in a travel soap dish with holes drilled in it. Works great! Power for that one is one of those little solar panels with a micro-USB port on it, used for battery-powered security cameras.
      - tomcam 4y ago
        Love that! Battery backup for night & downcast days?
        tlavoie 4y ago
        Yes, I have a 2200 mAh 18650 cell in there too, which the panel will mostly keep charged. In the darker, cloudier winter, I swap in a battery and recharge manually if it's not keeping up. Running on an Adafruit ESP32 Feather board, it wakes up, sends its current readings over Wi-Fi to an MQTT service (that is on a Raspberry Pi), and goes back to sleep for 10 minutes. A little daemon running saves to Sqlite database, and another ESP32 unit inside has its own sensor, as well as displaying both (outside pulled from MQTT). I've got some pictures and such, though haven't quite gotten to the much-belated blog post yet.
        sgt 4y ago
        Thought about getting a bigger solar panel for those cloudy days?
        tlavoie 4y ago
        Cloudy season, more like it, BC coast. ;) Really, if I do it every couple weeks or so, it isn't a big deal. I charge the inside one periodically as well, as I don't leave it plugged in. For that one though, I added a last-update time; with the e-paper display, it's not immediately obvious when it has run out of juice.
        tomcam 4y ago
        > haven't quite gotten to the much-belated blog post yet. Thanks for the preview. Looking forward to it.
- gh02t 4y ago
  These devices actually end up being kind of hard to engineer, measuring air temperature accurately especially can be kind of tricky. And then add in that for a weather station it has to be resistant to the elements and low power. Speaking from experience, you end up spending more money and a lot more work going the DIY route except maybe at the high end. You can get an Acurite temp/humidity/lightning sensor that is fine outdoors and batteries last for ages for like $25. Not that there isn't value to rolling your own, just I wouldn't assume it's as cheap and easy as you might originally.
- flyinghamster 4y ago
  > why did you decide to purchase ready solutions instead of rolling your own using ESP32 for a fraction of the price? I already had the sensors long before I had the SDR; they're paired with display units as well.
- simcop2387 4y ago
  It's not likely going to be cheaper to roll your own once you add a case and weather proofing and battery handling. These things can be had for as cheap as $15 on amazon, https://www.amazon.com/Crosse-Technology-308-1409WT-CBP-308-1409WT-Temperature/dp/B01LDFKF0U/ https://www.amazon.com/Crosse-Technology-308-1409WT-CBP-308-... or even down to $5 on aliexpress, https://www.aliexpress.com/item/1005003408554165.html https://www.aliexpress.com/item/1005003408554165.html Along with that using 433MHz means that there's a much longer range, and they generally also have much lower power usage compared to doing wifi, which makes the batteries last a lot longer.

hdjjhhvvhga 4y ago

My first thought was, "Why would I need SDR to read temperature/humidity from sensors", then I realized these are more like wireless weather stations. Out of curiosity: why did you decide to purchase ready solutions instead of rolling your own using ESP32 for a fraction of the price?

margalabargala 4y ago
Not the person you replied to, but someone who did the same thing: Most of the things inside my house are ESP32 or zigbee things I put together myself. Things that go outdoors, though, I'm much more likely to purchase an off-the-shelf solution for longevity's sake. Especially if the whole point of the item is to be rained/snowed on, be left in direct sunlight, and so forth.
- sgt 4y ago
  You can always build a tiny little house for your outside ESP and leave it outside.
  - tlavoie 4y ago
    Yeah, mine's under a deck, in a travel soap dish with holes drilled in it. Works great! Power for that one is one of those little solar panels with a micro-USB port on it, used for battery-powered security cameras.
    - tomcam 4y ago
      Love that! Battery backup for night & downcast days?
      - tlavoie 4y ago
        Yes, I have a 2200 mAh 18650 cell in there too, which the panel will mostly keep charged. In the darker, cloudier winter, I swap in a battery and recharge manually if it's not keeping up. Running on an Adafruit ESP32 Feather board, it wakes up, sends its current readings over Wi-Fi to an MQTT service (that is on a Raspberry Pi), and goes back to sleep for 10 minutes. A little daemon running saves to Sqlite database, and another ESP32 unit inside has its own sensor, as well as displaying both (outside pulled from MQTT). I've got some pictures and such, though haven't quite gotten to the much-belated blog post yet.
        sgt 4y ago
        Thought about getting a bigger solar panel for those cloudy days?
        tlavoie 4y ago
        Cloudy season, more like it, BC coast. ;) Really, if I do it every couple weeks or so, it isn't a big deal. I charge the inside one periodically as well, as I don't leave it plugged in. For that one though, I added a last-update time; with the e-paper display, it's not immediately obvious when it has run out of juice.
        tomcam 4y ago
        > haven't quite gotten to the much-belated blog post yet. Thanks for the preview. Looking forward to it.
gh02t 4y ago
These devices actually end up being kind of hard to engineer, measuring air temperature accurately especially can be kind of tricky. And then add in that for a weather station it has to be resistant to the elements and low power. Speaking from experience, you end up spending more money and a lot more work going the DIY route except maybe at the high end. You can get an Acurite temp/humidity/lightning sensor that is fine outdoors and batteries last for ages for like $25. Not that there isn't value to rolling your own, just I wouldn't assume it's as cheap and easy as you might originally.
flyinghamster 4y ago
> why did you decide to purchase ready solutions instead of rolling your own using ESP32 for a fraction of the price? I already had the sensors long before I had the SDR; they're paired with display units as well.
simcop2387 4y ago
It's not likely going to be cheaper to roll your own once you add a case and weather proofing and battery handling. These things can be had for as cheap as $15 on amazon, https://www.amazon.com/Crosse-Technology-308-1409WT-CBP-308-1409WT-Temperature/dp/B01LDFKF0U/ https://www.amazon.com/Crosse-Technology-308-1409WT-CBP-308-... or even down to $5 on aliexpress, https://www.aliexpress.com/item/1005003408554165.html https://www.aliexpress.com/item/1005003408554165.html Along with that using 433MHz means that there's a much longer range, and they generally also have much lower power usage compared to doing wifi, which makes the batteries last a lot longer.