Hello guys,
I am planning to build a weather station as an electronics project. It is supposed to be a couple sensors (temperature, humidity, air quality for example) connected to a microcontroller (probably via I²C, because I’m currently interested in that and picked this project as an excuse to do something with it), and a basic LCD display to show the current data.
For this I want a small microcontroller that can collect the stats from the sensors and show them on the screen, so nothing too fancy. I want to actually deploy this on my balcony, so I don’t wanna sacrifice a Pi or something along those lines. Ideally something with a sleep mode so I can run it off a button cell. In order to use I²C and an LCD screen I would need around 9-13 pins, depending on the LCD. Plus some additional pins for buttons, means something with at least 16 GPIO pins would be desirable.
I was eyeing out something from the ATtiny family. Ideally it would be a through-hole-mounted chip as I want to use it on a breadboard first (and probably permanently). The only DIP chips are fairly old tho so I’m not sure if they’re easy to use nowadays. We used an ATtiny461A in university and had to program it via a Windows XP VM, which is an experience I would not like to relive.
I’m not afraid to get my hands dirty writing raw C code without an stdlib.
While the WiFi functionality of the ESP32 is appealing, I don’t know if I want to condemn one of them to a life on the balcony. I would rather use them for one-off projects instead and use something simpler for a long-term deployment.
The following are some ideas I have that I might want to add to my project later, but they’re just optional features and I don’t necessarily pick the microcontroller based on them:
- Tracking/Logging sensor data over time, e.g. hourly. This would require some fairly accurate timing in order not to drift
- Networking, so I can access the data via my local network
If there exist microcontrollers that fit my criteria I’d be happy to hear about them! I’m not an absolute beginner to electronics, but I’ve never shopped for microcontrollers before.
If networking is the goal, choose any ESP32 module. If you want something simple akin to an ATtiny, ich can recommend the CH32V003. Is has plenty pins and an I²C peripheral, costs around 15 ct. For accurate timing, add an external oscillator instead of using the internal one.
Edit: You could also use an external real time clock like the PCF8563, then you’d have an absolute datetime and wouldn’t need accurate timing on the microcontroller itself. The buy the CH32 (and anything else), I would choose lcsc.com
The suggestion of using an external clock module is so obvious, I don’t know how I didn’t come up with it myself. Thank you for that!
I noticed that I glossed over your breadboard requirement. If you want to use something like an ATtiny or CH32, you could always buy some generic SMD breakouts like this. Both of these microcontroller series have internal oscillators and flash memories, so you really don’t need any external components. Maybe a bypass capacitor for good measure.