Emergency Stop Circuit
Posted: Tue May 29, 2018 7:28 am
Hi,
I want to add an E-stop circuit to my robot that doesn't depend on any software or smarts to shutdown the Roboclaw. (a watchdog).
I didn't see any examples in these forums, or online (yet). How does this look?
https://github.com/elicorrales/roboclaw ... ircuit.jpg
My thinking is that the capacitor will eventually charge, forward-biasing the transistor, then the relay shuts (it just has to be momentary if I set up the Roboclaw for latching ?) . (I could also look for some momentary-pull or maybe double-throw relay?)
The Raspberry would have to consistently pulse-low the output GPIO pin to keep the capacitor from charging up to where it trips the relay. The high-pulse or just a high would have no effect due to the inline diode.
A pullup at the output of the GPIO in case it's just floating . Or maybe the pull up should be on the output of the comparator. (cathode of diode).
thank you.
I want to add an E-stop circuit to my robot that doesn't depend on any software or smarts to shutdown the Roboclaw. (a watchdog).
I didn't see any examples in these forums, or online (yet). How does this look?
https://github.com/elicorrales/roboclaw ... ircuit.jpg
My thinking is that the capacitor will eventually charge, forward-biasing the transistor, then the relay shuts (it just has to be momentary if I set up the Roboclaw for latching ?) . (I could also look for some momentary-pull or maybe double-throw relay?)
The Raspberry would have to consistently pulse-low the output GPIO pin to keep the capacitor from charging up to where it trips the relay. The high-pulse or just a high would have no effect due to the inline diode.
A pullup at the output of the GPIO in case it's just floating . Or maybe the pull up should be on the output of the comparator. (cathode of diode).
thank you.