Another VoltLog InTheMail, this time I receive the following items:

  • ICR18650-26F 2600mAh 3.6V Rechargeable Li-ion Battery
  • NCR18650B 3400mAh 3.7V Rechargeable Li-ion Battery
  • 3S JST connector cable
  • DC-DC 0.9V-5V USB Output Charger Step Up Power Module
  • ESD Anti-Static Shielding ZIP LOCK Bags
  • Mifare RC522 RFID Induction Reader Module
  • 100 Pcs 0805 SMD LED Diode 5 Colors
  • Original Xiaomi 5000mAh Ultra-thin 9.9mm Power Bank
  • TI Precision Amplifier Quickstart Kit AMPQUICKKIT-EVM: OPA313, OPA314, OPA316, OPA170, OPA171, OPA172

Links for all of these are in the video description on YouTube.

May 23rd, 2009

RFID Keyless Entry

RFID Keyless Entry

Keyless entry has been used for quite some time in automotive industry by most car manufacturers even though such a system may not be in their standard package. The owner receives a card or a small device, much like a remote control, and just by approaching the car, no buttons pushed, the car senses the master and opens its doors.

In this project is presented a method to build your own keyless entry system. Your RFID will be a Nike footpod which will send the secret code to its iPod receiver. This receiver communicates with an Arduino Pro Mini  through an iPod Serial Board. The Arduino listens for the right code from the RFID and gives lock/unlock commands.

You can give these commands to your car’s fob or adapt it to the internal wiring of the door’s lock/unlock mechanism. This can be pretty tricky for there are several systems used for door locking. In some European cars like Volkswagen, Seat, Skoda the command for lock/unlock is given on a single wire. For example if on this wire the computer sees a firm ground then it will unlock if it sees a resistance to ground then it will lock or the other way around. In these case you will need to use diodes or relays.

Asian cars usually have two wires, one for lock one for unlock. You will need negative or ground to control these wires. Things complicate however with the more expensive cars as they use vacuum systems or sophisticated computers inside the door. Usually these cars when equipped with a factory keyless entry system have a sensor behind the door handle that must be triggered in order for the doors to unlock, even if the car senses its owner nearby.

Powering our keyless system requires that you find a permanent 12V supply in your car. Look at fuse box, under the driver’s kick panel behind the steering wheel for thick wires and use a multimeter to measure the voltage. Do not trust thin wires as their 12V can disappear after car’s computer falls asleep. Usually that happens between 15 to 30 minutes after locking the car. Be careful with this because serious damage can be caused.

Other difficulty you can experience, as the project’s author did, is the car’s door locking settings. If you unlock the door but do not open it the car might lock it again after a short period of time. You can change these settings from the car’s computer with a diagnosis tool.

RFID Keyless Entry: [Link]

April 15th, 2008

RFID Security System

 RFID Security System final assembly

Designed to replace the antiquated mechanical push button locks on doors, this easy-to-use security system is built around the embedded RFID tags in student ID cards. Of-course any other RFID enabled card could be used, with modification to the source-code.

The system can store codes from up to 20 different ID cards in the ATmega32’s EEPROM but if you need a larger storing capacity an external EEPROM memory can be inserted with adjustments in the schematic and source code. I think its cool how things evolve, and instead of building an access system based on password, you can easily build this RFID system.

RFID Security System: [Download Project][View Project PDF]



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