Physical emergency stop button?

I am thinking of adding a emergency stop button that connects to the OF controller via the Breakout Board (Pin 23). I find fumbling with my 10" display is a bit slow when things get exciting.

Looking for insights from someone who has done this? What switch did you use? Is it simply a momentary switch?

The controller switch just cuts power.
You could do something like this.

I don’t know about the breakout board.

I’m not talking about cutting primary power. I’m talking about replicating the emergency stop button on the controller display by using pin number 23 on the breakout board.

Hi Alan - looks like e-stop is pin 23.

I got an estop from Amazon but I’m not happy with the action; it’s far too soft and I’m concerned it might be pushed by accident. If you have a safe place for button that it won’t get pushed by accident, it should work fine for you though.


1 Like

Yes, it is pin 23. I think it works by simply grounding the pin momentarily.

The switch you linked looks like a locking switch that is released by twisting it. I have several of those in my shop on other equipment. Did you give this switch a try?

I am thinking a “momentary” switch is needed but I am not certain. That is where I am looking for experience. Does simply giving pin 23 5 volts momentarily get you the EStop? Does giving 5 volts again get you the release? In other words, the same action as the touchscreen?

Hi Alan - I purchased it and played round with it, but I never connected it. It is easy to push down and “engage”. I was looking for something with a little more resistance that requires a good “slap” to depress and lock.

My understanding is you just need to momentarily ground the estop pin. Based on the schematics, all the IO are 3.3v only, so never apply 5 even if the signal is active high. All the IO seem to have pull up resistors and decoupling capacitors so you don’t need to actively drive it - only ground it and let it ‘float’ high.

I really wish they isolated the pins on the connector from the microprocessor so you don’t fry it if something goes wrong, but they didn’t. I’m thinking about creating an interface board that properly isolates the signals and protects the uC a little more.


1 Like

Thanks Tom,
I will dig into schematics. I assume they’re in the Buildbotics manual/documentation.

Yes, that breakout board is crowded and could be a bit risky if exposed or treated badly by mistake.

Thanks for the help!

Buy yourself a proper estop button. example estop button