kickabit wrote: ↑Mon Dec 07, 2020 3:07 pm
I've started looking into building the myTimer mod. Any information you can share about getting components would be helpful.
I will describe my setup.
I love the jopa's idea of creating an adapter cable, basically the idea is to connect the pi to the buttons of the vivaldi and push them from the pi. To do that you need a
female IDC connector, a
male one, and a
ribbon cable with 16 pins.
Then you need a raspberry pi (zero w) and a relay board, I bought it
here, it is cheap (because you get two) and it does not draw excessive current from the rpi. To connect it to the pi you will need to solder wires (any conductor should be fine) to both or get a header for the rpi zero w (adafruit sells a pi with header soldered) and header terminated wires. Soldering is still required to get the shot timer.
Then if you have a micro-sd and a micro-usb power source, you should have everything. If you want the shot timer, you should get a
reed relay with a 12 V coil 0.5 A SPST with protection diode.
NB: I have made many mistakes in orderding as I did not know the system so I did not order any of the digikey parts above (except for the ribbon cable), but after much suffering I believe they should be right. Please do double check and think about the system first.
I did not implement either the energy meter either the manual/auto dose.
How did you add preinfusion?
Preinfusion is added via software for now, I have not implemented the hw to try it. If you do not have preinfusion and do not have the possibility to upgrade the board, there are three ways I can think off.
Easiest way: you add an on-delay relay between the triac/ssr and the pump, so that, when you press the brew button, the pump will be turned on after as many seconds as you want. This however is not controlled by the RPi and can only be changed manually (there's a knob on the relay).
Easy way: you add a relay board in the same position in parallel to the pump wire or to the solenoid wire. When the brew is started from the rpi, it will start the solenoid or kill the pump, wait and then finish. I think it is preferable to do it on the pump, because otherwise you need to find another live wire to run the solenoid. The issue is that pressing the brew button will not use preinfusion
Best (maybe) way: use two relays, one controls the pump, the other one senses the brew start. the raspberry pi will sense the brew and the pump will be dead, but will then start it, this will work with both the RPi and the brew button. It uses two relays (I believe you can reuse the same relay as the reed relay jopa implemented for the shot timer) and requires the RPi to be always online and working.
I realize my explanation is at best terrible, so please let me know if you want more information.
Would you recommend trying to track down a PI 2 or use a PI zero or something else?
I believe you have to find a raspberry before the 2, as the pinout of jopa's has 26 pins. My recommendation depends on how comfortable you are with tinkering with things. I can help you and provide you with my code, if you feel comfortable doing some debugging and working with a terminal.
I honestly really liked the RPi zero W as it is extremely cheap and readily available, it takes up no space and just does the work. Note, you need the W version to get wifi.
