Installing a Garage Door Opener Wired to Motorcycle Hi-Beam

I was tired of having to get on and off my bike to open and close the garage door each time I headed out.  While my wife and I were out of town we found a project at a dealer that allowed you to operate the garage door via the hi-beam switch.  It was $120 and more than we wanted to spend at the time (times two since we'd each want one on our bike).  Recently, however, I decided, "how hard could it be to come up with a simple circuit to trip the garage door opener from an existing circuit on the bike"?  The first one took a few hours of research, building, and a bit of trial and error.  This instructable includes the step-by-step instructions I used for our second bike to put it together in under an hour for $15 plus a garage door opener.

Step 1: Parts Needed

Here are the parts needed (Radio Shack mode # in parentheses):

 - 12VDC/125VAC 10A SPDT Mini Relay (275-248)
 - 1000 microfarad 35V 20% Radial-lead Electrolytic Capacitor (272-1032)
 - 10K ohm 1/2W 5% Carbon Film Resistor pk/5 (271-1126)
 - Project Enclosure - 4x2x1" (270-1802)

In addition, you'll need a garage door opener.  I used a Chamberlain Universal Garage Door Opener that I found at Lowes. 

For a nice, clean installation, I'd pick up some 18g hook-up wire, heat shrink tubing, and some wire-tap-in's.  You'll also need a soldering iron and solder for making the connections.

Step 2: Wire Up the Relay

I originally bought this particular relay so I could mount it to a circuit board, but the board did not fit into the project box along with everything else, so I opted to run the wire directly to the relay.  This relay is fairly compact, which helps to fit everything in, so I'd still suggest using it.

To make it easy to keep track of what was what, I used green hookup wire to run leads that would be attached to button on the garage door opener.  These are attached to pins #87 and #30 and are about 3" long.  The black wire is going to go to the capacitor and resistors (and then on to the headlight common wire).  It is attached to pin #85 and is about 3" long.  The red wire will run all the way outside of the project box into the hi-beam circuit, so it's about 12" long and it is attached to pin #86.  All connections have been soldered and then heat shrink tubing applied.

Step 3: Wire Up the Capacitor and Resistors

The capacitor and resistors are the key to converting the constant power of the hi-beam into a momentary pulse (to simulate a "push" of the button instead of "holding" it down).  You will need 3 of the resistors from the 5-pack.  Wire the three resistors together in parallel and then add the capacitor to the bundle.  I soldered them all together and wrapped it all in heat shrink tubing to keep it clean.

NOTE: Be sure to keep track of which side of the capacitor is positive/negative (the negative side is marked).  This is important for the next step as the negative side is to be connected to the relay.

Step 4: Connect Capacitor / Resistor Pack to Relay

Taking care to make sure you have the right end, connect the capacitor / resistor pack to the black wire coming from pin # 85 of the relay.  Then, cut another length of wire about 8" long and connect it to the positive side of the pack.  This will be the wire that connects to the headlight common wire.

Step 5: Connect Relay to Garage Door Opener

For this project, I used a Chamberlin Universal Garage Door Opener that I had originally picked up from Lowes.  I dismantled the opener and discarded everything except the circuit board.  Since I was going to install this in the enclosure for the headlight, I installed a new battery to make sure it would be a while before I needed to mess with it again.

On the back of the circuit board, I located the two contacts on the backside of the button that would trigger the opener.  You can figure it out by using a short piece of wire to connect the two points.  If it's the right pair, the garage door opener will trigger.  Make sure you test this before soldering it - as you can see from my image below, I attached to the wrong contact point at first and had to come back and fix it later.

Step 6: Install Into Project Box

Drill a small hole in the end of the project box so that you can run the wires out.  After that, *carefully* run the red and black wires through the hole and add the opener, wires, relay, and capacitor / resistor pack to the box.  It's a tight fit, but I was able to get it all in there snugly.  Be careful not to break any of the wires or solder joints during this step (especially easy to do if using solid-core wire).

When done, add the cover to the project box and you are ready for installation in the motorcycle.

Step 7: Installing the Project Into the Motorcycle

Feel free to wire it up wherever you like, but I chose to go with the hi-beam on mine.  You want to find something that has a 12v switched circuit to tap into.

If you go to the hi-beam on the lite, you will need to determine where you want to tap into the circuit.  On my Harley Fatboy Lo, the wires run directly from the switch on the handlebar through the forks, right into the headlight enclosure.  I found the best place to tap in, was right in the housing, directly behind the light enclosure.  I took out the headlight enclosure and accessed the wires the same way you would if you were changing the bulb.

Next you will need to determine which wires you need to tap into.  I have an H4 bulb, so the two outside contacts provided me the "common" wire and the "hi-beam" wire.  Figure out what kind of bulb you have and head to Google for some help with the wiring diagrams for your particular bulb type.

Using the wire tap-ins, splice the black wire from the project box into the common (white wire in my bike) and the red wire from the project box into the hi-beam (black wire on mine).  I had two black wires going into mine, but opening the connector I found they both went to the same contact point, so it did not matter which one I tapped into.

After that, turn on the bike and give it a test.  I found that mine would only work if there was a bulb installed.  Turn your lights on normal and then flip your hi-beam on and then back off to trigger the garage door opener.  You should hear the relay click and ideally the garage door should open.

Once you have everything tested, place the project box into the housing behind the headlight fixture and put it all back together.  I'd include photos of the finished product, but the beauty of it is - there is nothing to see  :)

NOTE:  I was initially wondering how hot it got in there and if that would be a problem, but after careful inspection of the other plastic and wiring exposed in there, I did not see any damage from heat so decided to give it a try.  After returning from a 280 mile trip where we used the hi-beam extensively, I'm happy to report that there was no sign of any overheating with the project box or components.