Yes, it's quite likely it does some form of entire bill capture and then comparison with an existing scanned template.
Not sure at what points it would switch the red and IR leds though?
Hi David
I work in the gaming industry for 7 years and I can tell you that your assumptions are correct. Firmware can not accept the newer bills.
Why before disassembling, BV have tended reading bills, but after reassembling did not want?
This implies two things.
1) This model BV with these firmware accepts banknotes without an master machine. But exist are also firmwares and BV models which waiting to command for the initialization eg. using RS232 or USB from master device.
2) after disassembling and reassembling sensors pcb´s probably occurred to change relative position of sensors, respectively some dust has moved away or disappeared, was added in lenses. It is enough that in the BV going mistuning settings (some older models are highly susceptible) are prone to it and need to do calibration using a calibration paper.
In principle, the job description of each BV is as follows.
After inserting banknotes is interrupted scanning beam (beams) and will start the bill transport motor. The motor speed are continuously monitored in real time to achieve, if possible, move step by step, somewhere is also used for this purpose also normal stepper motors.
At each step, the recorded image of the sensors stored in RAM.
They also tested the length of banknote.
The resulting image is compared with the template in a certain tolerance transverse position notes. The sensor records, some symbols inside the banknote using a beam that shines through the paper and some sensor is the reflective for colors testing on the surface .
Also used a magnetic sensor for sensing the metal strips in banknotes and in addition to infrared, red, green, blue and white beams are also used in the UV.
I think about I will send you some intelligent coin acceptor to you investigate if you would like, which can be programmed for any currency.
Henry