How to Implement an Emergency Power Cut-off for mBot Ultimate 2

#1

A competition requires that all movement of the robot be stopped in case of some emergency. I have explored software methods, but this question is about a dc power disconnect switch. 1) any electronics issue with disconnecting the dc power supply only for emergencies. 2) is any switch okay, looking for one that has fast snaping action. 3) I want to buy pigtail dc cables with the male and female versions for 5.5(OD) and 2.1 (ID) barrels but can’t find any with the shorter barrel length which appears to be 9mm. Is this length barrel commonly used in other applications.
We are currently using the battery pack but have order the rechargeable accessory from MakeBlock, do you see any impact that would make any of the above concerns. Thanks for any help.

#2

@Hugh

  1. You shouldn’t have any issues with disconnecting rapidly, it already happens when you turn the switch.
  2. Any typical switch will do (not sure how you plan to hook it up…) but make sure that you connect the wires and that the robot does not turn off due to a short circuit.
  3. I’d rather go with something a bit long than too short. Here’s an 11 mm one, you can probably find other sizes:
    https://www.amazon.com/Pigtails-Female-Connector-Pigtail-Security/dp/B08PYWN3T7
    Just search barrel connector on Amazon and you’ll find something.

The robot should move at about the same speed as a normal battery pack for a while, though the voltage might be a bit lower, but I don’t see any concerns here either.

#3

Thanks, great to have re-assurance and advice from someone experienced with this product.

#4

Thanks again and just a couple of follow questions. So the slider switch on the MegaPi does not have any extra protection electronics just breaks one or both of the dc power leads. If it’s just one, is the positive or negative. Just would like switch to match the same pattern.

#5

To be honest, I’m not sure. I have a MegaPi Pro (I don’t have an mBot Ultimate with it). @CommandeR knows lots of mBot things, maybe he knows something about mBot Ultimate or your situation.