Powering Lopy with solar panel
I want an advice for powering Lopy with solar panel, in order to guaranty 3 month of autonomy ( a project to monitor temperature )
and this is what I found in the net:
@jasonriedy I followed the broodminder hardware a time ago. I had a look again and I'm positively surprised what they have now on start. Interesting, the scale design looks really similar to my bar, great that it is not about temperature only now!
I thought about BLE also but we decided to use RFM69 and now RFM95 or the LoPy in the future when power saving mode is implemented fully. We did also some first investigations about NB-IoT so I was really exited to see the GPy and FiPy.
Broodminder transmits data to a mobile device nearby only, do I see this right? So there is no distance monitoring. This would be a main feature for me, or "that" feature. Monitoring your bees far away. So a BLE connection only makes not too much sense for me. But in case you can replace the BLE mobile phone with a LoPy and sending data to the internet ... interesting! ;-)
@Clemens Thanks! The Open Hive project was another possibility, but we're going to use the BroodMinder Bluetooth sensors to relay possibly multiple hives over some LPWAN (hopefully LoRaWAN, but placing antennas is tricky).
@jasonriedy: My bee monitoring system "Open Hive WiFi Solar" is based on an ESP8266. It's running with a tiny 0.5 W solar cell and a 1200 mAh LiPo as buffer. The solar cell is optional, it could also run of batteries. I'm using the CN3065 as charge IC, the Seeeduino Stalker has it also on board. You can search on ebay for small and cheap break out boards. The CN3065 is not so elaborated, especially it has no under voltage protection but in the most cases you can count on the LiPos build in protection (also when all companies write you shouldn't).
You can see the power consumption in this chart:
As you can see voltage is ascending even with low and minus temperatures in Germany from January to March 2017, Voltage is heavily oscillating, there is a voltage divider with high values and a capacitor missing on the prototype. Also max voltage is not quite correct, is in real around 4.2 V not 4.3 as in the graph.
My initial thought at project start was that a WiFi devices is hardly power by a small solar cell but I was impressed that its doable. Of cause all depends on your update cycles and it is not doable with the currently implemented deep sleep on the LoPy. But I think (and hope ;-) this will be improved in the next weeks.
Here is a picture of the Open Hive Wifi Solar: The parts: Base is an Adafruit HUZZAH ESP8266 (blue PCB), the load cell IC a HX711 (green) and the solar charging IC a CN3065 (red). The white PCB is a custom board.
The complete board front and back. for production I will de-solder the charging indicator LED.
This is the other System based on an Seeeduino Stalker with GPRSBee for communication. You see the small waterproof box with a transparent top and the 0.5 W solar cell:
Open Hive System with electronic (in the middle), humidity / temperature sensor for inside (left) and outside (right), at the top five temperature sensors for inside and bottom the scale unit.
thank you, good to know, I sould learn more about lopy deep sleep I guess!
@maamar Personally, I'm hoping the deep sleep mode will be enough for our bee hive monitoring project to use batteries. I've also considered https://www.voltaicsystems.com/iot , but just batteries would be cheaper and less intrusive. (So long as no one sees electronics, nothing is likely to be stolen. Well, except the bee hives, but we'll find ways to secure them.)