I’ve been reading this thread in detail since I found it, due to the fact that plenty of the things discussed here are common to my project… so, first of all, thanks so much for all the infos placed here !
I had my core laying in the drawer for too much time, and in the past days I decided to use it for designing my own weather station, taking “inspiration” from the AirPi project (link)
In fact when I started I wanted to have on the board the basic weather sensors (temp, humidity, pressure, wind and rain) but after seeing how many pins I had unused on the core, I decided to add some air quality sensors, and the AirPi was a good starting point for me, before finding this thread!
I checked also other projects, some of them are listed here (like smartcitizen) and after some tinkering I decided to build my board with the following components:
- Spark Core (of course!)
- DHT22 for temperature and humidity measurement
- BMP180 (breakout board) for pressure (and further temperature)
- Figaro TGS2600 for Air Contaminants
- MICS-2710 for NO2
- MICS-5525 for CO
- LDR for light
- 2 RJ11 plugs for wind & rain sensors
- 3 GROVE style connectors: 1 for extra ADC channel, 1 for I2C and one for serial port (all with GND and VCC)
As you may see, there are a couple of common items , and seeing that there are some discussion for the aspect of the new board, I though that my comments could be useful to somebody, so this post.
- DHT22: in my opinion it has to be placed vertically, otherwise its readings will be altered by the PCB heat and - hopefully not - also by the heaters of the nearby sensors.
- PSU: I totally agree with the 5V supply! if the max voltage on board is 5v, 12v are a total waste. With 5v PSU you can skip the voltage regulators, and have your board powered by a lot of things (powerbanks, USB everything, etc)
A note about the two MICS sensors MICS-2710 & 5525): I searched a lot but it seems that the only place where to find them is at wicked devices (link) but the two of them will cost roughly 75 USD, too much for me.
Thinking also to the future “life” of the board, I think I will have to switch to a SMD component, and a nice option could be the MICS-4514, which houses both sensors in a single package. If I don’t find cheaper suppliers for the TH sensors, I will go with it.
About my project - AirSpark! - I’m finishing defining the schematic in these days: after that I will start a thread in this forum, of course publishing all the project documents. Every comment will be more than welcome!
I hope to have been useful to somebody, in any case thanks for having read all this