Wireless Horn Button
While working on the Sunbeam Tiger I decided to swap out the steering column. Then I realized that the racing column from Sweet Mfg had no provisions to do a horn wire. No fault of theirs it's a racing column. To make matters worse it uses a Quick Release adapter to the steering wheel.
Options are make a coiled cord assembly and disconnect harness, use the high beam flasher on the turn stalk to trigger the horn, or think of something out of the box.
Well in my modification of the Turn Signal stalk for the Sweet column I had to cut off the high beam flasher part of the switch. That would have been so easy to do, and just would have been connecting up one simple wire.
Enter the CrAzY idea I had, how about a wireless transmitter stuffed into the steering wheel?
The Good : I can have a horn button in the right location and a quick disconnect steering wheel hub without any wires.
The Bad : SEE CAUTION BELOW, It will have a battery and related electronics, it requires a 1" steering spacer, and I have to make it.
CAUTION : DO THIS PROJECT AT YOUR OWN RISK. THIS CAN BE A DANGEROUS PROJECT IN THAT THE BATTERY CAN FAIL AND YOUR HORN WILL NOT WORK WITHOUT WARNING. THIS IS FOR OFF ROAD USE ONLY.
Transmitter Mounting Fitted
The fiberglass board is easily cut with tin snips, and then a quick touch on the belt sander makes it a tight and perfect fit.
Wireless Transmitter Kit
So my idea was to open up a small key fob type of transmitter and make something of that, but given the power of the Internet I poked around and found exactly what I need on eBay. Their are plenty of import kits, the one I picked up was from this seller - Wireless Remote Control Manufacture The kit I picked up was Momentary Transmitter Kit and was under 10 bucks shipped from China, and it took about 5 days to get it. The receiver comes in a small plastic case (not shown) and has a small relay that seems capable of driving a pair of horns directly (max of 20amp). I would say still may be a good idea to use a Bosch style relay as the final horn relay. For more information on Horn Wiring check out the page on Horn Wiring in the reference section.
Wireless Remote Kit
These are the parts from the wireless remote kit. The transmitter right next to the quarter and this is the part that will be mounted inside the steering wheel adapter. The battery is a typical A23 12 Volt battery which is commonly used in many remote controls. The battery holder is a bit tricky to find, but ePay came though again with about a 2 dollar buy from HERE. The Receiver comes in a little plastic case that pops open. This part will be connected to your horn or other circuit. The little black curly wire is the antenna and care need to be taken not to break them off.
Momo Steering Wheel Adapter and Pattern
This is the Momo (aftermarket) 25mm steering wheel adapter. The ID of the adapter was traced on a piece of prototype circuit board material, but most any rigid material should work. If you use metal make sure it doesn't short out any of the wiring or transmitter circuitry.
Mounting the Transmitter and Battery
To be safe I used a large diameter shrink wrap tubing over the entire transmitter circuit board. The battery holder can be secured with a small screw and/or tie wrap. Note that if using screws the heads must the really thin or it will keep the battery from fitting the holder. Drill a couple of small holes to feed the wires to the back side. I sanded down the heads of off a couple of 4-40 flat head screws and bolted it down. I also used the tie wrap just to be sure (yes, it will have to be cut to replace the battery). Drill a 2 small holes to make a strain relief (maybe 3/16"). This will be used to keep the wires that go to the horn button from pulling the wires out of the transmitter.
The rest of the stuff is the wiring. I'm going to just tell how to do it as I'm too lazy to draw something up, but don't worry it's easy.
The Transmitter has 2 wires a RED and a BLACK. The batter has 2 wires a RED and BLACK. Connect the BLACK from the battery to the BLACK of the transmitter.
Connect a 6' to 8" thin piece of stranded wire to each of the RED wires, one from the transmitter and one from the battery. You should solder them and use heat shrink tubing to insulate them.
Feed these wires though the 2 holes to create a strain relief, then attach 2 FEMALE spade connectors (or what ever your horn button uses).
That's about it. The Transmitter is activated when you power it up, the horn button completes the circuit and causes it to transmit a signal that will in turn cause the receiver to close the relay and honk the horn.
Momo Horn Button Adapter
This is the stamped Momo horn adapter ring. It's about 8 bucks and is needed as it does NOT come with any of their wheels it seems.