The goal of this project is to create a heat circuit using the BeagleBone Black that can be toggled on and off remotely using RESTful APIs. The BeagleBone can only deliver about 3.3V @ 6mA from its GPIO pins.
So, using Ohm's law, we know that the maximum resistance R = V/I so 3.3 / 0.006 = 550 Ohms. This will also only put out about a 20th of a watt of power so it won't be the greatest heater. And really, you'll want to go lower than the maximum to avoid damaging things. so closer to 4-5 mA would be safer.
A better design would be to use an external power source and use a transistor or MOSFET to drive the heating source.
- BeagleBone Black with Ethernet or WiFi enabled
- 47 Ohm Resistor
- 680 Ohm Resistor
- TMP36 Temperature Sensor
- BC550 Transistor
- 5mm LED Diode
- Jumper Wires
Path: /api/temp
Sends temperature value in Fahrenheit
Path: /api/heat/off
Force heat off
Path: /api/heat/on
Force heat on