fingerprint sensor doesn't work

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lina
 
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Re: fingerprint sensor doesn't work

Post by lina »

The time varies before the error message pops up

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adafruit_support_rick
 
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Re: fingerprint sensor doesn't work

Post by adafruit_support_rick »

How about the RX and TX leds?

If the error message does not pop up instantly, then that suggests to me that SFGDemo is trying to communicate with the sensor, but it is timing out.

That would mean that you have a problem with your connections. If I knew whether or not either of the LEDs was blinking, that might narrow it down a little.

Also, I asked before if the sensor flashes when you first apply power. Does that happen?

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lina
 
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Re: fingerprint sensor doesn't work

Post by lina »

Rx blinks tx does not. The red light comes on and off when arduino is connected to the usb port

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adafruit_support_rick
 
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Re: fingerprint sensor doesn't work

Post by adafruit_support_rick »

Alright. That means that the sensor has power, and that SFGDemo is connected to the Arduino and trying to talk to the sensor.

So, the problem is in the serial connection between the arduino and the sensor.
First of all, make sure the connector on the sensor is pushed in all the way. Here's what mine looks like:
FP Connector.JPG
FP Connector.JPG (443.21 KiB) Viewed 344 times
Next, try a different way of connecting the two serial wires to the arduino. I'll share my experiences with fingerprint sensor connections:

I soldered my wires to regular square header pins, and inserted those into RX and TX on my Uno - similar to what you have done. Believe it or not, this did not work very well at all. SFGDemo could connect, but it really didn't work at all for enrolling or scanning fingerprints.

So, I tried going through a small breadboard. With the wires still soldered to the header pins, I connected the sensor to the breadboard, and then used jumper wires to the Uno. This worked flawlessly. The lesson is that the serial connections from the sensor are tricky. You have to be certain that the connections are rock-solid.

Here's a couple of pictures of my breadboard (Ignore the GPS breakout board - it's not connected to anything...)
IMG_0789.jpg
IMG_0789.jpg (376.51 KiB) Viewed 344 times
IMG_0790.jpg
IMG_0790.jpg (310.05 KiB) Viewed 344 times

vincent1234
 
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Re: fingerprint sensor doesn't work

Post by vincent1234 »

I have the same problem, the Rx blink but not the Tx. :x

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adafruit_support_rick
 
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Re: fingerprint sensor doesn't work

Post by adafruit_support_rick »

vincent1234 wrote:I have the same problem, the Rx blink but not the Tx.
All I can do is to recommend the same solution.

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