This blog documents some belated progress on my Star Trek themed Pi IoT design challenge entry. It is being put in the arduino area since that is where it is most useful.
I wanted to make the subsystems useful and built well enough to work reliably in their target environment, so this sensor array is built using a custom PCB.
The PCB did not arrive until well after the challenge was over, but it worked perfectly with no errors when I assembled it.
The card features an arduino pro micro which has a couple of quirks to be aware of:
- Sketches can defeat the USB so to get back into programming mode, you need to push the reset button twice, which reactivates the USB for 8 seconds, hopefully allowing you to get your software load started.
- I used the 3.3V variant of the pro micro so it could directly connect to the Bluetooth module. This cpu runs at 8 MHz so you need to be sure the compiler is aware of the clock frequency, or all communications timing will be messed up. I installed the pro micro board type in the arduino IDE using this instructional note:
Other features of the card include an HC05 Bluetooth module, a Nokia 5110 LCD, a DHT11/22 temperature/humidity sensor a power switch, a reset switch, a solar panel connector and battery connector a recharging circuit, an I2C connector, a couple of input connectors (analog or digital).
Since I had to order a batch of 10 (for $10) I designed the card to have a little more general capability than just a remote temperature sensor.
The card has extra connectors for more sensors, but the main addition is an LCD connector, allowing it to be used as a stand-alone weather station.
Here is a video showing the system in action:
The android app was developed using App Inventor 2 from MIT.
Links to the Pi IoT Design Challenge site:
Links to blogs about the Star Trek IoT Alcove project: