RASPBERRY PI POWER

We’ve built our first circuit – both on and off the breadboard – using our 3V battery as our power source. But, there’s no reason we couldn’t power our circuits with another power source. For example, some breadboards come with special built-in power supplies so that you don’t have to use a battery or another external power source.

One of the features of the RaspberrySTEMTM is that it can use the power and ground from the RaspberrySTEM base to power the breadboard on the lid. The power is actually coming from the Raspberry Pi computer, and is made available to the breadboard through the connector board at the top of the lid.

In this project, we’re going to replace the 3V battery we’ve been using as our power supply with the internal power provided by the RaspberrySTEMTM and the Raspberry Pi.  Other than replacing the battery with a different power source, our circuit will remain exactly the same.  In fact, our schematic won't change, other than to replace the power source with 3.3V (the voltage of the Raspberry Pi power source) from the 3V provided by the battery.  

Here is a reminder of that schematic:

And here are step-by-step instructions for how we make the change to the circuit:

Step #1:  Disconnect the 3V battery

First, we need to disconnect our existing power source. From the breadboard, remove the power and ground wires leading from the battery.

Your breadboard should now look like this:

Lighting an LED (Battery removed) Diagram

Step #2:  Add power and ground from the connector board

We can now add power from the connect board to the breadboard. This is accomplished by running a wire from one of the pins labeled “3.3V” on the lid connector to the red (power) row, thus providing power to the entire row. And then running a wire from the blue (ground) row to one of the pins labeled “GND” on the lid connector.

At this point, our LED should once again be lit, and here’s what our breadboard should now look like:

Lighting an LED (Power connected) Diagram



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