Electronic safety-lock with telecars as key


Posted on Feb 7, 2014

Most of the source code of this project its based on my Telecard reader projectof my web site. The components for this project arefew and ordinary, thatmeans low-cost and easy-to-be-found. The `keys` are empty or not telecards (Phone cards. Not cell phone SIM cards), that can befounddiscarded on any telephoneboothwith no additional charge. To learn more


Electronic safety-lock with telecars as key
Click here to download the full size of the above Circuit.

about telecards read the phonecards_204. zip. This circuit doesn`t write any data to the telecard. The ATtiny26 reads the 16 first bytes of telecard and then store them in to the internal eeprom of ATtiny26. When you insert any telecard in to the telecard holder (telecard`s slot) will be pressed the switch SW1. The ATtiny will seethat a card was inserted in to the slot and reads the card. Temporary will save the 16 first bytes of the card to the RAM and after that the ATtiny will search in to its internal eeprom to see if this telecard wasregistered to the system. if not, it will turn-on the Red LED. The ATtiny has 8 groups of 16 bytes each, summary 8*16=128 bytes of eeprom memory. With any telecard in to the slot, press the SW2 forregistering the card in to the system. The ATtiny will search the internal eeprom for empty memory group (1 group=16 bytes with $0F values). If there is empty group, it will read the 16 bytes from RAM and store them to the eeprom. Then, the ATtiny will reboot, reset the telecard, read it again and check if the card is registered (by compare the 16 bytes of telecard, with 1 group at the time, with internal eeprom). Now it will turn-off the Red LED and turn-on the green LED because we have registered this telecard in to the system. At the same time it will arm the relay connected to PB6 pin via BC547. If for some reason youdon`t want to use any of the 8 registeredtelecard, youcan un-register it...




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