My Arduino Nano undershield

Arduino Nano undershield powering 10 servos from Bajdi on Vimeo.

My Arduino Nano undershields arrived this week from Iteadstudio in Shenzen, China. I received 12 PCB’s, but I only have one Nano, anyone want an undershield for your Nano? My undershield has a 3A 5V LM2576 switchmode regulator to power the Nano. All the pins from the Nano are brought out to male headers with a 5V and GND header next to it. This makes it very easy to plug servos and sensors on the board.

The LM2576 regulator is strong enough to power a lot of things. I quickly soldered up the first PCB and did some testing before I plugged in the Arduino Nano. All seemed ok so I plugged in the Nano and connected a couple of servos. The LM2576 5V voltage regulator was still giving a nice and stable 5V with 2 servos. I then connected 10 micro 9G servos and let them sweep, the regulator started to get hot but it was still acceptable. The 5V line dropped a little when the servos switched direction, but the lowest level I saw was 4,8V which is still good.

I was bit worried that the power spikes from the servos would reset the Arduino but I didn’t have any problems. I just need to fit a heatsink to the LM2576 regulator to keep it cool. I’m very happy. This is the first PCB that I designed in Eagle and had made in China, and it works 🙂 It is a small and simple PCB, only 50x50mm. The smallest size that you can order from Iteadstudio. The combination of the undershield with the Nano makes for a powerful and compact package. It is about 25% smaller then an Arduino Uno although it has much more powerful 3A 5V regulator. I will use the undershield in my line following robot.