GoPiGo3 power connection


#1

Hi all, I’m looking to buy a regulated 12V 2A DC power supply for the GoPiGo3 but not sure about the size of the connector.

This page:
https://www.dexterindustries.com/GoPiGo/learning/hardware-port-description/
says:
“Power Port: The Power Port on the GoPiGo is a 5mm Barrel Jack that can receive 9-12V power.”

But what size tip is required? Is it 2.1mm like on this unit?

Thanks to anyone who can help.


#2

Just measured the power connector on my GoPiGo3. It’s 5.5mm center positive. The page for the rechargeable NiMH battery pack lists the size of the connector as “DC female barrel jack, 5.5-2.1mm” (I guess the hole in the center is 2.1mm).

I can’t find any spec. for the current use of the GoPiGo3, but the GoPiGo2 lists 800mA-2A (running motors, camera, servo, and Raspberry Pi Model B+). I’d imagine the GoPiGo3 has similar current requirements.


#3

Thanks, that’s useful information.

The specs for the GoPiGo3 don’t give quite enough information:
https://www.dexterindustries.com/GoPiGo/learning/technical-specifications-for-the-gopigo-raspberry-pi-robotics-kit/

Operating Voltage: 7-12V
Current usage:
-> 300-500 mA (Idle with the Raspberry Pi Model B+)
-> 800 mA-2A (Motors, camera and servo running with the Raspberry Pi Model B+)

Matt from Dexter Industries provides some more detail in a post, particularly when he says 'To run motors without batteries, I recommend that you use a 9-12V DC regulated power supply (center positive), and plug it into the battery input barrel jack. Ideally it should be rated for 2A, but 1-1.5A might still work okay. I have extensively used 12V power supplies for developing with the GPG3.'

I don’t know if a 12V 2A supply allows the GoPiGo3 to be equipped with several sensors as well but I’m guessing the Raspberry Pi board and the motors are the biggest power users and the sensors are a minimal overhead.


#4

The motor current changes significantly depending on the physical load as well as the supply voltage. 1A should be adequate to run both motors under the worst case conditions (12V, full power, physically stalled).

The Raspberry Pi current draw could be anywhere from maybe 200ma up to maybe 1.5A (depending on the RPi model, connected devices, etc.). Since the RPi is on the 5v rail being powered by a switching regulator (“buck regulator”), 1.5A at 5v would be 7.5W, which at 12v would only be 0.625A (about 0.7A factoring in the protection diode voltage loss and the efficiency of the regulator). 1.5A is higher than I have ever measured a RPi 3 to draw, even with WiFi and Ethernet connections, so it should be a very safe number.

Each sensor connected to the GPG3 draws probably 0-100ma (depending on the sensor) on the 5v rail, which is negligible. The GPG3’s onboard circuitry, LEDs, etc. are also minimal; maybe 150ma max on 5v.

Servo current draw under typical operating conditions should be no more than maybe 250ma each, but it depends significantly on the servo used. These also run on the 5v rail.

To add that all up, that’s almost exactly 2A on the 12v rail, and a lot of the numbers above are pretty much worst-case scenario.

The barrel jack on the GPG3 is indeed the standard 5.5mm X 2.1mm.