Fingerprint scanner indicating “came” or “left” an employee for ACS?

Question

Time Management

Greetings.
I choose a fingerprint scanner to track the working hours of employees.
The task is for the scanner, when a finger is applied, to somehow inform the user - by sound, the color of the light bulb, or by text on the display - he has come or gone. Suddenly, the user puts his finger twice in a row and the program thinks that he came and immediately left. Therefore - came - it is green. Leaves - she is blue. Did not pass the test - it is red. Something like this. The time interval settings are not suitable for my tasks. Need an indication. Please tell me what are the options.
Thank you.

Answer 1

We just have 2 terminals at work, one for arrival, the second for departure. I think you need to do the same. Nevertheless, there are still overlays, even after you have been read, the next day you find that you are not in the database and manual adjustments still fall on the immediate supervisor.
He reads me from the 5-10th time, pisses me off, it’s clear that this case completely excludes the possibility of checking in for an employee ... but I don’t understand why it is necessary to fence such things, instead of the usual dismissal of those who are being shaded.

Answer 2

We have over 80 people. We use 1 scanner at the entrance. From the Chinese manufacturer ZKTeco. Before entering, the employee presses the F1 button and puts his finger, and when he leaves, he presses F2 and puts his finger. Everything is very simple. We use the Workly
time tracking program . Works well without a hitch. All good. Try it.

Answer 3

I would think in that order.
1. NFC terminals and tags.
2. 2 cameras (input / output), OpenCV for face recognition and photos of employees in the database.
3. Fingerprint
scanners scanners are the most unstable, especially at different temperatures of the environment and fingers.