# Pololu Pushbutton Power Switch SV - Parallel SWs

I am building a swarm of robots. I am thinking of using the Pololu Pushbutton Power Switch SV. There are conditions:

1. All the robots have to be turned on from a single switch. They can then move away.
2. Each robot must have an emergency power off switch.
3. The amperage requirements of the robot exceed the 10 amp limit of the SV switch.

My proposed solution is:

1. Use multiple Pololu Pushbutton Power Switch SV on each robot. Each controls a separate set of circuits. The main separation is that the left and right side motors will have separate Pololu Pushbutton Power Switch SVs. Control electronics, etc will have another Pololu Pushbutton Power Switch SV (or two).
2. Have a plug on each robot that connects to the external “ON” switch. The plug pulls out when the robot moves away.
3. A single switch on each robot is connected in parallel to the main “ON” switch to serve as the emergency off.

The big question is whether the Pololu Pushbutton Power Switch SV will operate properly with a single switch (the “ON” switch) connected in parallel to the plethora of Pololu Pushbutton Power Switch SVs?

Would there be a limit to how many of the Pololu Pushbutton Power Switch SVs could be connected to a single switch for turning them on?

Also, can the power connections on the Pololu Pushbutton Power Switch SV be operated in parallel. The motors on each side may need more than the 10 amps so could two be parallel to provide 20 amps?

Rud

I think you’re trying to push the design further than it’s intended to go. The on/off function of the switch makes a simple parallel connection more iffy.

I would probably get some relays for the high current, and use the on-switch to drive the relay coils. You only need a single switch to drive multiple parallel coils.

However, paralleling across multiple robots might still be problematic. Perhaps you should wire the relays to be latching, and use another switch to turn them on. You’ll probably want a diode to prevent current from being pulled from that switch to the motor, to be able to parallel that switch.

The emergency button can be a normally-closed pushbutton, in the loop for the coil, so pushing it breaks the coil, which breaks the relay, which breaks the latching.

Rud,

I second jwatte’s assessment that the Pololu pushbutton power switch is not appropriate for your application. One of the features of my circuit is that it uses the same switch for on and off, but you don’t need that, which makes things a lot easier. You can use basically that same latching circuit, but rather than toggling it through the single button, have one input for “on” and one input for “off”. If you make it yourself, you can also just make it with a big enough MOSFET so you don’t have to deal with putting smaller circuits in parallel.

- Jan