02 Schematic
Schematic
The main page is composed of CPU (PIC16C57), an Analog Switch (4051) where are incoming the switch signals for the KEY programming, the DIP-SWITCH of configuration (to matrix) and of the local key hole. Then the outgoing CF (false key) and CO (coercion) and the 3 inputs CL NOT ready to the insertion. Finally it has been previewed a connection to the PC for eventual future uses, or, in order to download the access details on a thermal RS232 printer, in such way to have the report of all the access operations!!
The second page introduces a Shift Register, that controls the output to LED and the RELAIS, then there is the I2C bus to which the TP are connected for the internal insertor connection, the operationals like buffer for the external key hole at EEPROM 24C01 memory for the memorization of the codes. The buffer for the management of the remote key hole, has become necessary because the distance between the key hole and the card can be of 100 meters. During the TESTS, it has been verified the operation with cable antitheft standard (0,22 for signals and 0,5 for the feedings) for a distance of 100 meters even with a rolled cable or with a straight cable. The transistors PNP Q7 and Q8 serve to find the presence of the key in the key hole. Finally it can be noticed the local power source with separate regulator for the local electronics and the remote one, that comes fed with 0.6V over just in order to compensate the tension fall on the cable.
