Currently, I have a control board that I want to control using a microcontroller. Currently, this board works by choosing a program by pushing and releasing one of the buttons on the right, and then click the most left button to start the program. I'm thinking of hacking the board by removing the physical button switch, and somehow use the microcontroller to emulate the button push and release instead, and then delay for a second, and then emulate the button push and release on the start button. Is my concept doable? if so, how should I wire the board?

concept wise, it should be similar to using a relay to short and cut off the circuit. but it seems like a relay will be too overkill?

 

You could possibly use an optocoupler to emulate the switch and also provide isolation.
Need to know the voltage across the switch.

 

I should be fairly trivial to do it with a micro, what are the voltages present on the switches and a little more info on the circuit might help?

 

Welcome to AAC!

Sure it is doable. The details depend on what is connected to the board and what the equipment does.
Often, multiple switches on a keyboard are multiplexed. This makes a clean digital solution more complex.
The brute force solution is to control five small reed relays that are wired across the leads of each button.

 

@crutschow @MaxHeadRoom @MrChips I'm sorry but to be honest, I don't have the board with me right now. I bought the brand new appliances and I'm thinking of hacking it so that I can control it using WiFi. However since i'm way too scared to hack a brand new appliances, I'm planning on buying the spare part and hack the board first, so I can't tell the voltages on the switch for now. I will update if i can find a schematic or anything. The board itself is a display board, so it should be fairly low in terms of voltage, should be between 12-24V

 

Get 5V reed relays and you don't have to worry about what voltages are on the board.



https://www.aliexpress.com/item/4000188472602.html

 

Or for even smaller foot print, 4 pin opto's !

 

@MrChips @MaxHeadRoom thanks! By the way something popped up on to my mind. Is it possible for me to still have the button functionality I don't remove the push button switch, but add the optocoupler/reed relay parallel to the switch? I assume that this should work right?

 

Yes, but dependent on how the present switch is wired,
circuit detail.

 

Yes, but dependent on how the present switch is wired,
circuit detail.

Great! will update about it after I can get my hands on the spare parts. thanks for everyone's help!

 

Seems like i can't find the schematic for the display board. The only thing I can find is the older version of it which is already more than 10 years old, but i think it should behave similarly. I'm not sure what can I find from this though since I don't know how the connections are.

 

In the absence of a schematic, Normally you would start by doing some basic reverse-engineering of the board, it would appear from the picture it may easily lend itself to this?