I have just purchased my very first raspberry pi zero 2 with the intention of making a weather station and clock for my desk. Along with the pi, I also got :
Inky WHAT e-ink screen,
BME280 temp/pressure/humidity sensor breakout
RV3028 Real-time clock breakout
Unicorn HAT mini RGB board
I have just started to put things together, and figured out that the inky screen plugs straight into the raspberry pi, using all the pins. Then I realized, how am I supposed to attach all the breakout boards, if all the pins are already used by the screen?
I noticed that the screen comes with a header that sandwiches the pi and gives me all female pins on the back. So could I use that to add a breakout board, which I can then plug in my breakout boards?
Sorry if this is a dumb question! I am just beginning on my first raspberry pi project today. If anyone has any suggested links on how I can put all the above breakouts onto one board with the screen, I would really appreciate it!
The Inky-What has some pins broken out (left lower edge on the back). This gives you the I2C-pins that you need for the BME280 and RV3028.
I see no option that you use the Unicorn Hat together with the what, even with some pin-multiplexers, since both hats use SPI and share a chip-select pin.
Another thing to consider: your readings from the BME280 will be heavily off unless you operate the pi zero in on/off mode.
Awesome! I didnt even notice those pins on the bottom left. Thanks for that!
Is there a way I can stack both the BME280 and RV3028 together on those pins?
I forgot to mention, I also have a pimoroni 5x5 RGB matrix breakout that is the same size as the other breakouts, so perhaps I could get all three on those breakout pins?
It makes sense that the temperature of the pi will interfere with the temp sensor. Perhaps I can wire that up so it is some distance away? Or 3d print a shield or something. Or I can just use its other features, and just use it for pressure/humidity and get the outside temperature in code.
The 5x5 RGB matrix also uses I2C. I2C is a bus and you can just chain the devices (as long as each device has a different address). So this matrix should work.
Having wires for the BME280 will help you in the short run. But copper is a good thermal conductor and the core of the Pi-Zero-2 gets hot even in idle mode. So you will encounter heat-creap sooner or later. And the humidity reading is influenced by temperature (pressure is independent though).
I would connect the BME280 to a microprocessor (e.g. Pico-W) and send the data to the Pi-Zero-2 using WLAN to display it. And I also would skip the RTC, because the Pi-Zero-W will query the time from internet automatically. Unless you run it offline, of course.
But since this is your first project, keep it simple. Set it up as planned and make it run. You know your readings aren’t correct, but that is not the point. You will learn how to wire things and install, implement (and fight) the software and after everything is running, you can think about optimizations.