I am working on an access system, multi-user code for entry to restricted areas. I designed one that uses purely hardware but its a bit complicated and bulky, though it works perfectly. Might you have any ideas on implementing microcontroller based systems. Any information would help me at this stage as i am still investigating my options.
Post by RT
These days smart card technologies are used for access system in most places. It uses a RF card the size of a Credit card with a microcontroller embedded in it. and you need a smart card reader that needs to be networked or interfaced with PC. philips, atmel, maxim, fujitsu and many more sources for kits, products and parts. many embedded 80C51 family type solutions were there when it all started.
Contactless smart cards
A second card type is the contactless smart card, in which the card communicates with and is powered by the reader through RF induction technology (at data rates of 106–848 kbit/s). These cards require only proximity to an antenna to communicate. They are often used for quick or hands-free transactions such as paying for public transportation without removing the card from a wallet.
Like smart cards with contacts, contactless cards do not have an internal power source. Instead, they use an inductor to capture some of the incident radio-frequency interrogation signal, rectify it, and use it to power the card’s electronics.
Study Resources Below
A Smart Card and a Card Accepting Device (CAD) communicate via means of small data packets called APDUs (Application Protocol Data Units).
Modules for Smart Card Microcontroller, Examples for application level Communication, Connection of a Smart Card to a Microcontroller, Instructions for Smart Card current measurement.
When this post was first made 8 links to sites with info was added by me. Today 2012 most of the links are broken. So new sites are listed.