As we progressed further in the program, the competition became more fierce and the road condition were getting .... more interesting. The roads were now longer and with just 2 allowed passes (recce), it's not easy to memorize the entire road. We knew communication will be crucial to keep us ahead of others and more importantly, to keep the car on the road. We had to do something.
As we blogged before, pacenotes is an important tool to notify the driver what is coming ahead. All this while, I (Keng) found no issue hearing notes delivered by OBK. Of course he can, the exhaust doesn't make apparent noise, the road is smooth & the suspension is comfortable, basically, we weren't rallying. When we moved to gravel surface, all we could hear was gravels hitting the undercarriage of the car, I would go like, "notes? what notes?". We were desperate for intercom!
Later, some team invested on pricey rally intercom set (point finger at team Sparken hehe), some got themselves motorbike intercom set and some even went as far as communicating via cellphone with hands free kit. As for us, we opt for the motorbike intercom set too but they didn't perform that well as there was just 1 earphone for each of us and the microphone picked up noises other than OBK's too! We were very much dying for a better intercom but we needed to keep the budget at minimal, so I put my DIY skills to work and came up with this ...read on
Materials that you need:
1) Helmet (Old AGV, cost Rm70 if I remember correctly)
2) Headphone with 3.5" male jack (Rm19 from LowYat)
3) Heatshrink (Less than Rm2/ft from Jln Pasar)
4) Cable ties (Dunno how much they cost as I got them from my toolbox)
5) Wires for extension (Leftover from my car project)
6) Bike intercom with 3.5" female jack (got this from ebay for less than rm70 plus shipping)
Tools that you need:
1) Hot glue gun + hot glue
2) Wire cutter
3) Pen knife
5) Solder gun + flux
6) Philip screwdriver for dismantling the headphone
7) Power drill for drilling hole for the mic boom wire or
8) Small flathead screwdriver if you don't have a power drill
Step 1: Where should the headphone go?
Most crash helmet comes with a detachable ear padding for easy cleaning. If yours doesn't, skip this part & go to step #2 yo. Now remove the ear padding. Mine had a velcro to keep it in place.
Step 2: Make that hole bigger
This is an underskirt shot of where the (ear) padding used to sit. All you have to do next is to make the hole larger so that there is enough room for the earphone. You don't want it to be 'ketat', or do you? Rule of thumb I got from my wiring experience, measure twice, cut once!
Step 3: Strip 'em
You'll need a "circumaural" type of headphone as this completely surrounds the ear & seal them from external noise, perfect for rally! The model that I bought was actually 3 bucks more expensive than a model which had no striking red color cover behind the earphone. Soon I realized it's not needed, crap.
Remove the ear muff (hehe) and loosen the screws to detach the headphone from the main assembly.
Step 4: Connectoooo...
At the back, you'll find 2 wires connected to the speaker. You need to unsolder them as the wire connecting the left and right speaker goes through the main loop, or you can choose to cut them but you'll need to connect them back later. DON'T cut it, solder is cleaner!
Now measure if the wires (left to right speaker) are long enough, you'll need to tuck these wires underneath the padding of the helmet later. Remember to use heatshrink if you need to increase the wires length, they look nicer & they provide extra grip so that the solder doesn't come apart. Don't solder the MICROPHONE just yet!
Step 5: The ear muff
Secure the speaker phone to the ear padding that we took out in step #1. Hot glue will come in handy here. And you can even use the screws that were originally used to hold the speaker to the main assembly.
Step 6: Mic check....1..2 ...1..2
Drill a hole right behind the ear padding for the microphone wire to go through. You can use the same hole to mount the mic boom onto the helmet.
Step 7: Final assembly
Secure all the connections properly. I didn't prepare a wiring diagram beforehand, all you gotta do is just put them back together like how they were before you took them apart.
Step 8: Taa-daa
There you go, rally intercom helmet!
Now from here, you've several option on how to zhng your rally helmet. And this is what I did LOL. I'll show you how to do them in the future!