Hardware E-stop

[JamesNewton]

Single Power Cut E-stop: Power cable between the robot and power brick is re-wired into an estop switch box. The negative side is directly connected, but the positive wire is broken by the switch. The power brick positive wire is connected to one side of the switch and the robot positive wire is connected to the other side of the switch. These units are pre-made and commonly available. For example:

• https://www.amazon.com/mxuteuk-MXU-DT-JH-Stainless-Waterproof-Connection/dp/B07RXP2CH2/ref=pd_sbs_3
• https://www.se.com/ww/en/product/XALK178F/control-station%2C-plastic%2C-yellow-lid%2C-1-red-mushroom-push-button-%C3%B840%2C-turn-to-release%2C-2-nc/

Group Power Cut E-stop: Power cables come from each robot to the estop switch box. A single, larger, power brick plugs into the switch box to provide power to all the Dexters. It might be worth having a network hub included so all cables run from the same point and only one network connection is required for up to 4 robots. This will allow very rapid physical emergency shutdown of all robots and will simplify connections.

[JamesNewton]

Note that this is not the same as a software e-stop #10

[JamesNewton]

A power cut e-stop will not work in cases where the robot is carrying a load which is delicate or dangerous as that will cause the load to be dropped. An external input into the FPGA which triggers an all stop and hold maybe needed as software e-stop can not be trusted in all cases. If no pin is available on the motor board, perhaps the PMOD connectors on the FPGA board can be used.

[JamesNewton]

Kamino cloned this issue to HaddingtonDynamics/OCADO