Intro:
This is a new thing I want to start doing where I try to build something at least once a month, and within a day (ideally). To kick things off I wanted to test, and build, a simple arduino powered temperature and humidity sensor. This overall took about three hours including testing of planning, sensors, wiring, testing, and coding.
Build Overview:
The build needed to meet two criteria:
- Read both humidity and temperature reliably
- Be able to connect to a RaspberryPi later (Part: ii)
To meet these criteria an Arduino was used. While a RaspberryPi alone could have been used, the added complexity of separate system communication had more appeal.
Components Used
| Part | Description |
|---|---|
| ELEGOO UNO R3 | Single-board microcontroller |
| Generic LCD 16x2 Screen | Shows up to 32 characters. Gives immediate readable data. |
| IC2 Adapter | Simplifies wiring and control for the LCD display. |
| DHT11 | Three pin variant of DHT temperature & humidity Sensor |
| 2 x LED | Show state of executed code |
Final Result
See companion code here. The design is very basic, and is nothing new. There exists a miriad of setups like this online, and is only intended to setup the ground work for part ii. The added step of adding heat-shrink did make the build overall look and feel more stable.
Whats Next?
The next step is to, ideally, pull local weather data from the internet, and have a website hosted locally that shows all relevant data into a single landing page. I have not done any research on free-ish api’s or data I can pull from but there are a few things I want to gather if possible:
Desired Data Points:
- Radar.
- Local temperature and humidity (as close to my house as possible).
- General air quality.
- Wind speed and direction.
- Moon phase.
Another goal of part ii is to employ NASA’s The Power of 10: Rules for Developing Safety-Critical Code. While the code written in the following phases will not be considered critical, the challenge of following these rules seems interesting.
Takeaways:
- IC2 adapters are awesome. Easy to solder, cheap, and they make the process of interfacing with LCD screens like these much easier. I highly recommend them, especially if they are preinstalled.
- The DHT senor seems to fail every 30 readings or so. I am not sure why. But with limited testing it seems to be reliable enough for it’s purpose. Additionally, I compared the ambient readings with a store bought thermostat and humidity reader. The humidity was identical, but the temperature seemed always off +/- one degree. A tolerance I am more than willing to accept.