Several key steps were achieved since the last time we wrote about our project:
Firstly, we checked if the gear we want to use is functional (aka the deep fryer to heat water at a specific temperature) . We also finished part of the circuitry board, that will contain most of the electrical components of the power managment
Secondly, we defined and tested the communication protocol that will be used between the Raspberry and the Arduino. Two functions are already working for the Arduino board, but the Raspberry’s side is yet to be done.
Thirdly, we managed to create a PWM output with a long period on the Arduino board: since we want to regulate a thermal process, which is slow by nature, there is no need to have a high frequency on the PWM output that will be used to control the resistance’s power. On top of that, we are using a Solid State relay to manage the Alternative current : this relay will cut the current only when it is at 0A (since we are on a 50Hz alternative current with a simple resistance, it will occur every 20ms). No need to have a PWM way faster than 50Hz, since it’s the fastest switch speed we will achieve in the end.
There is still a lot to be done, but we will get there, little by little !