I've had a remote start system in my car for a while, but never used it much because I was never satisfied with the safety aspects of it. I've heard of several instances of cars "running away" when someone forgot to leave their shifter in neutral with the parking brake sufficiently engaged, so without some additional safeties I was reluctant to use the feature as much as I would have liked to.

This weekend I finally completed my "modifrications" to the car and am now reasonably confident I can use remote start without running over anybody.

If you're new to the concept of remote start it's simply a system to allow you to start your vehicle remotely, usually via a 2-way pager/alarm system, for the purpose of pre-warming or pre-cooling the car (depending on your climate). Remote starting systems are not a new idea, but implementing them on a standard transmission car is tricky, since there is always the possiblity the car has been left in gear instead of in neutral. Automatic transmission cars have a built-in interlock that won't start the car unless the transmission is in park or neutral. Manual transmission cars use a "clutch interlock" that prevents the engine from cranking if the clutch is not depressed, but that interlock must be bypassed in order to use the remote start feature, which leaves a safety issue.

Some systems address this by only arming the remote start feature if the clutch is raised at the time the engine is shut off, reasoning that if the clutch is up the transmission must be in neutral. While this is better than nothing, it does not preclude the possiblilty of the gear selector being moved after the car is turned off.

If the S2000 had a neutral switch it would be a simple matter to connect it to the remote start system to disable remote start if the transmission was not in neutral. Since it doesn't, I thought of several ways to build a neutral switch (mounted to the gear shifter below the boot) but the limited space and short throw of the gear lever were serious obstacles. So instead I settled on a 2-way safety system tied into the parking brake and speedometer.

You can't use the factory parking brake switch as a safety because it is designed to ensure the brake is off, which means it senses brake position at or near the full OFF position. Applying the parking brake even one 'notch' will satisfy the factory switch but will not provide enough braking power to keep the car from moving. I needed a sensor to activate only if the brake was fully ON. To accomplish this I installed a micro-switch inside the tunnel which is activated by a bracket that clamps to the brake rod. The clamp is attached with a single machine screw which allows easy adjustment and the overly-long screw does double-duty by serving as the switch activating lever. See photo below.


When the brake is pulled up all the way the rod moves and activates the switch which is wired to bypass the clutch interlock, allowing the engine to crank. If the brake is not fully set the clutch interlock keeps the engine from cranking. In addition, I have a circuit to activate the brake pedal switch (simulates pressing the brake pedal) if the parking brake is released after the car starts. If this occurs the remote start system thinks the brake pedal has been pressed and immediately shuts down the engine (the brake pedal shutdown is a standard 'anti-theft' feature on remote start systems).

The second safety is tied to the speedometer sensor. The factory speedometer sensor produces voltage pulses when the gears in the transmission turn. I took advantage of that and built a circuit to activate the same brake pedal switch when a speedometer pulse occurs. This means that if the car moves more than a few inches the engine will shut down.

Testing the brake safety was easy, but to test the speedometer safety I jacked the rear of the car off the ground, left the transmission in first gear, and temporarily bypassed the parking brake safety switch. The speedometer safety shuts down the engine remarkably fast, as shown in this short video, link here. The beeping you hear is 1) the remote start pager, and 2) the Passport SR1 beeping when the ignition circuit powers up.

I am not going to be selling any of this stuff because of the labor required to make the parts, but you can get a pretty good idea of the brake switch arrangement from the photos. If anyone is interested I can supply a schematic for the speedometer circuit, which is only 2 transistors and a few other parts.

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wow... id be interested in doing this for my car... sitting in my car waiting for it to heat up is a royal pain in the ass...

what brand remote start do you have? is there such a system in which i can use the factory transmitters (i already have the hornet 700 alarm system)? all i have to do is get the remote start system all wired up... then add your components to it and i dont have to wait for my car to heat up??

thanks!

 

Incredible modifry

 

Modifry does it again....

 

this is incredible, thanks for the excellent write up.

 

Nice. You are a really paranoid guy.. lol.

You should set the car up in like a parking lot with lots of room, and try out your remote start mods. See how far the car goes forward.

 

That's a similar setup Clifford has with their alarms. I can't autostart my car unless my e-brake is completely up.

-Trung

 

[QUOTE]Originally posted by jackdeth99
Nice.

 

Modifry - I'd be interested in the schematic for the speedometer circuit since I'm getting ready to put my remote-start paging unit into the S2k.

I was thinking of putting some kind of reed switch thing in with the shifter, but you're right - not much space in there.

Thanks for the good work! I'll let you know how it works out for me, but it may be a few weeks until I can find the time to put it in...

 

wow goodjob on that.

JDMpress: sorry about that door