- The necessary components for the MSP430 to be operational are quite simple: only a CR2032 battery for power, two decoupling capacitors, a pull-up resistance on the RST pin. Note some pins connected to TX, TEST, RST and GND have been soldered in order to facilitate the programming and debugging of the MSP430.
- The cluster in the top left corner are the LDR in a potential divider with the 10k resistors and the TMP36 temperature sensor: light levels are then directly read with the pins analogue A0, A1, A3 from the MSP430, and the temperature from A4.
- The rest is just a lot of wires to connect the MSP430 to the transmitter NRF24L01, the colour code is used to facilitate the wiring (sorry for brown --> GND but black looked messy)
On the software side, the micro first convert the analog read from the temperature sensor to celsius degrees. Then combined with the light sensors, they determine the level of coffee: full, half, low or empty. Finally the temperature and the coffee level is sent to the receiver to be uploaded on the web.
The coffee jug transmitter circuit is implemented on a stripped board:
Messy Middle man NRF24l01 to ESP8226:
Level of coffee followed by its temperature: