Automatic Chicken door
Automatic Chicken door
Here is the automatic door I built with an automatic car antenna. I chose the antenna method because it has a built in stop when it reaches its end in both directions. This eliminates the need of more circuitry to control "run time".
Mine runs off a little 12v lawn tractor battery. The battery is kept up to charge with a "float" charger. The door opens and closes with a photo light sensor. The reason for the battery is so that a power failure will not cause a problem. The reason for the light sensor is so that the length of daylight does not need to be constantly adjusted on a timer. BUT, you can simplify things and use an ordinary appliance timer plugged into an AC outlet, and then use a 12v DC power supply to power the antenna.
This is just one way to use an automatic car antenna. With some imagination you could probably come up with many more designs.
As you can see the antenna is mounted upside down. The door is made from an 1\8" ALUMINUM panel. It is light in weight but very strong. The door channels are 1/4". I have a 3" spacer connected to the tip of the antenna to the door. You can measure the distance you need to determine the spacing length. I used a piece of aluminum stock and tapped each side to mount it. The side on the antenna tip has a hole for the tip to set in, and then I used the tapped hole as a "set screw" to keep the tip in place. I have my tip connected towards the bottom of the door. This makes the length of the door channel a bit shorter in order to match the up and down stroke of the antenna.
Be sure to carefully measure the lengths and travel distances needed for the antenna to move up and down freely.
If you do not have some aluminum sheeting lying around, you can find some at Lowe's or etc. Aluminum can be easily cut with your skill saw. Just make sure you have a carbide blade and wear safety goggles.
The door channels can be purchased also at Lowe's or Home Depot.
The best price for the antenna was on-line at Beachaudio.com. Just look for the least expensive "Pyle" brand. It was about $35.00 The antenna has three wires. Two connect directly to your power source. The other (green wire) is the "up down" trigger. That is the wire that you connect to the timer or sensor circuit.
If you go with the 12V battery, the float charger can be bought at Harbor Freight Tools for under $10.00.