Arduino Nano breadboard power supply
The Arduino Nano has a few convenient power options:
- USB power. The Nano gets 5v from the USB port and provides 3.3V and 5V out.
- Regulated 5V in, applied to the 5V pin. You can power a second Nano from one that is plugged into USB by connecting the GND and 5V pins of the two Nanos together.
- VIN – Power applied to this pin goes through the 5V regulator on the bottom of the Nano, which provides 5V out, and powers the microcontroller and 3.3V out. The minimum voltage here is 5V + The regulator dropout voltage, usually around 1V. The maximum input voltage to VIN varies depending on the regulator used – It is supposed to work from 6V – 20V but I have had circuits burn out when using a 12V unregulated plug pack on VIN (at low current the output voltage was more like 16V). If you’re going to apply more than 12V to VIN, it’s worth adding some additional components- at least a 12V regulator and a diode for reverse polarity protection.
Using a breadboard power supply.
A breadboard power supply is a small device that has a USB and/or DC in connector, and pins on the bottom that plug directly into your breadboard. They usually have 5V/3.3V switchable, and some can provide 5V on one side and 3.3V on the other side. You can use up to around 12V in with these. They don’t handle higher voltages much better than the Nanos I have used. They are cheap and use cheap voltage regulators with low maximum input voltage – you get what you pay for. Still, it’s a convenient method to get power onto the breadboard once you move away from the computer and USB ports.
You will need a battery holder that holds several batteries in series so that the total voltage is >5V, and <12V. The battery voltage is applied between VIN and GND. Not shown in the image above is the connection between 3.3V out on the Nano to the top power rail (I was wondering why the radio wasn’t working!). The battery holder I’m using has 2 pins on the bottom which I’ve plugged directly into the bottom power rail, which VIN is connected to.
You could position the battery pack more nearly and add some additional wires to VIN.