For an emergency/safety switch, it is not wise to just kill all power to the robot, since that kills power to the computer. Our current MCB has separate circuits for main(computer. peripherals) and motors. Most safety switches are for the motors only, but killing motor power would still leave the robot moving due to momentum, and if the robot was on a slope, it would start to drift down hill. An ideal ‘stop’ switch would keep the robot’s cpu running but would lock the motors with hysteresis.
For a Magni, the best way to wire a E-stop would be to remove the motor power push button next to the charging plug, and positioning the switch to the top of the robot.
Alternatively, one could attach a wireless E-stop to the motor power circuit. (I am not sure, but I think this voids any warranty with Ubiquity Robotics.)
I am uncertain if turning motor power off and continuing to run the motor node would cause loss of odometry information. If motor power is turned off an then on. The robot might behave erratically