Keyless Entry System Using the Arduino

2 thoughts on “Keyless Entry System Using the Arduino”

1. Bruce Harkness says:

   October 22nd, 2008 at 6:51 am

   Alex,
   Great job man! Your Arduino door opener took me back in time. In the mid 1970s my roommate and I built a door opener like yours using the remote control guts of an old Motorola TV set from the 1960s. This was the “works in a drawer” model tube TV that is now all but forgotten. The remote had four buttons, channel up and down and volume up and down, and that was all it would do. Not much, but better than poking your TV with a broomstick, which was what most people were doing back then. Each button was attached to a small spring loaded hammer that would strike a metal bar and ring it like a zylophone, only at a pitch slightly higher than human hearing. The TV electronics would pick up the tone, decode from which bar in the remote it came from, and one of four latching relays would move the channel or volume control one notch at a time. We took the guts out, screwed it to a bed post near the hinge side of the door, and used a wire and coil spring to twist the knob and pull the door open. Back then a servo would have been much too weak and expensive so we had the output going to a large solenoid taken from the mechanical assembly of an old washing machine. That was because the TV relay didn’t have enough power to pull the knob. It made a huge clang as it pulled the knob and opened the door but it worked most of the time, maybe 9 times out of ten. The slow swing of the door was erie and almost as good and the loud clang judging from the startled looks of the poeple who knocked on our door. The ultrasonic remote was barely loud enough to reach the sensor circuit from outside if we laid it on the floor in front of the crack under the door before pressing the buttons. Since nobody had a similar remote we were safe from thieves. Good stuff!

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