Current and voltage rating of magni

1

Hello,

So I am trying to install an emergency switch on the magni. I am going to connect it between the red wire of the magni and the live of the battery.

So I was wondering what kind of push button switch rating (in terms of voltage and current) should I get?

2

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

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3

For wheel cutoff emergency switch please see our writup on this page: McbConnectorsAndLeds | Learn Ubiquity Robots and ROS

For a year or so now we have been shipping switch boards (the board with our power switches on it) with a jack that you can use to for your own motor power ESTOP switch. There is no need to make PC board modifications these days.

See near the end for ‘Making A Remote RF Estop switch’.
If you do not need RF hand controller then just connect a switch that is normally closed to our switch board jack of P202. When you need to kill power to the wheels open the switch.

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