Fingerprint Sensor & 8mhz 3.3

[whaleboy]

Hello!

I recently purchased the adafruit fingerprint sensor (which is awesome) and have been using it for the past several weeks prototyping on a vanilla Arduino Nano. Finally got my code the way I wanted it, and since this would be battery powered I moved it over to an Arduino Mini Ultra by Rocketscream (http://www.rocketscream.com/shop/mini-u ... compatible)

Well, after I moved everything over to the Fingerprint sensor it runs VERY inconsistently, if not at all. I'll list the behavior so perhaps somebody can identify what's happening.

When I run the adafruit Fingerprint sketch, the sensor will come on and stay on for random periods of time. Sometimes for only 3 seconds, sometimes for 10 seconds and anywhere inbetween. Then the sensor will turn off for a few seconds, and serial print messages from the main loop will pause.. And then it will start up again. Again, sometimes for only a few seconds. Rinse, wash, repeat.

Now the sensor is currently being powered by 5volts. Based on another post I came across, I tried wiring it up to 3.3. Now, it does turn on, but the led lights in the sensor have weak output and it won't verify at all. But it no longer turns off randomly. Which I find interesting.

Another note, I originally was using AltSoftSerial, and the behavior was different.. When using that library it would consistently only stay on for like 2 seconds at a time, and then pause at like 2-3 seconds a time.

Could this perhaps be an issue of the input or output TTL being 3.3v or 5v? Some type of issue with running the library at 8mhz and how it interacts with the software serial libraries? Any suggestions? I'm very much a novice at this. :(

Thanks!

[adafruit_support_mike]

The best thing to do in a situation like this is take the system back to its last known working condition and start making changes one at a time, testing each one to make sure the system still works as expected. The hardest problems to debug are the ones that come from the interaction of two or more untested changes.