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FabienFerrero / UCA_Board

Gerber Layout of the UCA board
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Ultrasonic Sensor Damaging Pro Mini 3.3V Board #3

Open mccarr opened 6 years ago

mccarr commented 6 years ago

Hi Fabien,

I saw your new version 3 has pin support for the HC-SR04 Ultrasonic Distance sensor. The HC-SR04 is a 5V device and I've found it doesn't work with 3.3V input (so have others on the internet apparently). The echo pin outputs 5V which is fed into one of the inputs of the Pro Mini board.

I think this could potentially damage the board. According to the ATMEGA328P datasheet, the maximum safe voltage on any input pins is VCC + 0.5V. So if you are powering the device by a typical 3.6V (or thereabouts) battery, the 5V input could damage the Arduino Pro Mini.

I actually recently destroyed a board by doing this. Maybe you could include a word of warning on your page where you mentioned the Ultrasonic sensor?

FabienFerrero commented 6 years ago

Hi,

Thanks a lot for your comment. I do not check that HC-SR04 doen't work properly on 3.3V (because it was giving values !).

I'm going to add the warning.

See you

Fabien