Arduino connection to Finger print sensor

Other Hardware Sensors
1

Hi,
First up, this is my first Arduino Project and also my first hardware project. Im actually a software engineer and my knowledge of hardware is limited.
I was following the tutorial at Overview | Adafruit Optical Fingerprint Sensor | Adafruit Learning System and I have made the wiring as it suggested there. The issue I am facing is that the finger print sensor is not on continuously. As in the orange light indicating that the sensor is on does not stay on. It just flickers from on to off when I make the connection. I have tried using a bread board to make the connection, use the different slots(if I can call them that) on the bread board and also tried to make the connection directly to the Arduino board with out the bread board, but the result is the same. The light in the finger print sensor comes on and then goes off. Any idea why this is happening and what I can do to fix it? Any help is appreciated.

Thanks.

2

You need to understand how the software works.

Does it only light up when the software tells it, prompting you to swipe your finger ? That's how mine works.

3

Yes, its suppose to stay on. Sometimes (very rare, like 1 out of 15 times) the light does stay on for around 5-8 seconds. During this time, it detects my finger. Otherwise , its a dead device. Im just trying to wonder if the fault is with the Arduino board or the wiring or both. Same thing happens when I connect a magnetic stripe card reader to the 5V and GND on the Arduino board - the light blinks on it and goes off. It does not make any sound when I swipe a card through it.

4

Any help?

5

I am not familiar with this device. The tutorial you linked to, looks quite straightforward.

Are you getting any serial communications from the device at all ? Have you tried the method of connecting it to a PC ?

The next suggestion would be to post your question in the forum at the adafruit website, because perhaps nobody here knows about it.

6

According to that tutorial, that device draws 150mA at peak. If you've got any other hardware attached, you may be getting close to the Arduino's limit of 200mA.