Need to power a Raspberry Pi, Arduino, or other device from a 24V AC source? These 24V AC sources are common for sprinkler controllers, doorbells, and thermostats. This is a quick guide to how I am doing it to power my Raspberry Pi.
1 – 24 V AC source (Assuming you have a 120/24 Transformer with 24V AC.)
4 – 1N4007 Rectifier Diodes
1 – LM2596 Buck DC-DC Adjustable Step Down Power Supply
1 – Capacitor (I’m using a 22 micro farad unit)
1. Place the 4 1N4007 rectifier diodes in the solderless breadboard as depicted below.
2. Install an appropriate capacitor on the DC output of the diodes as depicted.
3. Tie in the LM2596 DC-DC converter to the output of the diodes.
4. Tie the 24V side of the transformer to the diodes as depicted below.
5. Power up the transformer and adjust the DC-DC converter appropriately until the output measures 5V.
6. Tie in a connector to the 5V output of the DC-DC converter so that you can plug in a Raspberry pi.
7. Power up the Pi and hopefully it’s working!
Picture of bench top setup for testing with Raspberry Pi running: