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Pixy2 only works with Arduino Uno under USB power


Hi there. My new pixy2 appears to work fine with an Arduino Uno (tested with “helloworld” etc) BUT…

…only when it is powered via USB power (any USB, not just my PC but also a USB charger). If the Pixy2 is not connected in this way, it appears to crash the connected Uno. So if I try to remove USB power, nothing works at all, not even uploads to the Uno.

If I remove the connection between the Pixy2 and the Uno (have checked all connected correctly) then the Uno instantly springs back to life. I have tried two different cables with no luck. Any ideas? Thanks


It sounds like a power issue. How are you powering your Uno? USB? Battery? If you are powering your UNO over USB it should be fine, as Pixy is going to use the same power.

Battery can sometimes be an issue because the regulator on the UNO may not be able to provide enough power. Please check out this page for more information.




Thanks for reply. The Uno is USB powered. The same thing happens using another Uno so it appears to be something to do with the Pixy


Should add this Pixy2 is a replacement for a Pixy1, which failed to communicate with the Uno at all. Has left me wondering exactly how reliable these things are.


Sorry for the problems.

Hmm, it definitely sounds like your USB power is “browning out” because either your host computer isn’t supplying enough current, and/or there is too much current consumption through your USB port. Are you using a USB hub to power your Uno? (Sometimes you can get significant voltage drop and/or current consumption from the draw of other devices and cable losses.) Please try removing the hub between your computer and your Uno.

The other thing to check is the USB cable between your host computer and your Uno. Not all cables are created equally. Lower-cost cables use smaller gauge wire, which will cause voltage drop. Also, sufficiently long USB cables can be a problem – make sure your cable is 6 feet or less. Pixy2 came with a USB cable that has good current-carrying capacity, but unfortunately that cable has a USB micro connector instead of a USB-B connector, which the Uno typically needs, depending on your version of Uno…

Finally, are you using a Raspberry Pi? If so, how are you powering your Pi?