I bought an OEM factory alarm system (mainly to keep genuine Honda keyfobs) with the optional hoodswitch. On top of this I bought a Mobile Guardian GPS tracking system that adds additional security and will text message me if my alarm goes off. My main concern though is having my top slashed open by someone looking to take my seats or my (unfortunately very visible) sattelite radio. My friend with an '00 S had his seats jacked once and it's always bugged me that it could happen to my car. (Of course, he was in Berkeley at the time and I don't plan on going up there anytime soon )

Anyway, I did some searching on the board and many people suggested that you could get an aftermarket radar sensor and just plug it in to the hoodswitch outlet in the OEM alarm box. Great, except I'm already using that outlet for the hoodswitch itself. If it's a simple case of "trigger alarm if signal on X-wire" then I supposed I could make a custom Y-harness for it. I used to build solar-powered race cars in high school, so I'm no stranger to a soldering iron, but I don't want to start splicing wires if it would affect the performace of either the hoodswitch or the radar sensor. Any thoughts on this?

Also, about the radar sensor, how sensitive would it be? Since the car is a soft top than conceivably just a strong gust of wind could set it off. Does anyone have experience with using these sensors on an S2000?

 

The hood switch connects the signal wire to ground when the hood is lifted. It is a passive device (just a mechanical switch). If you place your radar sensor output (mine is hot and gets grounded when triggered) in parallel to the hoodswitch, it should work well. If you worry that if the hood switch being grounded (hood lifted) would damage the radar sensor output, put a diode in series with the radar sensor output so that it can't tell if the OEM sensor input is grounded by another device (hood switch). Orient it so that it provides a path to ground via the radar sensor output. It's a way of putting several grounding switches in parallel while isolating them from each other. Only the OEM sensor would know that it was pulled to ground. I would do this anyway, since it costs a few pennies and would prevent your radar sensor from damage. Your only worry is to check to see if the radar sensor signals an alarm condition by switching its' voltage to ground. Otherwise you may also have to interpose a small relay. I have my radar sensor in the console under the arm rest in the center, but I don't know if the '06 has a similar space. I am also assuming that the '06 alarm is the same as my '01. You can easily check by checking the hood switch when the hood is up or down.

 

Aside from the wiring aspects, the sensor can be triggered by wind or rain. When parking in a garage with a lot of concrete surfaces, the alarm was much more sensitive. That was part of the reason I ended installing it under the console and modifying the console to be easily opened. I had to adjust the sensitivity controls whenever I was in that garage. I ended up getting a hardtop after I got too paranoid about vandalism (top was cut by some nut before the alarm). Also remember that the additional power to drive the radar would consume power when the car is inactive. In addition, if the alarm goes off, there is power drain through the horn. False triggering by the radar sensor is more common than under other circumstances, since it needs to be sensitive to be functional. Since I didn't drive every day, I had to jump-start the car several times. This was not good for the battery.

 

Thanks for the help! I didn't even think about the two units interacting that way but a diode there makes a lot of sense as a precaution. I don't want to damage either one but knowing it's a straight switch gives me a better idea of what to do. I'll have to test it out to see if the relay switch is necessary but if I checked the wiring diagram on the radar sensor before picking one out I may be able to figure that part out ahead of time. I'm pretty sure my center console has less space than yours since I have a larger cupholder design but I haven't gone inside of it to see how much room there is. I suppose where it goes depends on what size sensor I choose.

Considering all the issues you've had though, like false alarms and battery drainage, I'm having some second thoughts. I park in a steel parking structure at work that has far more surfaces than a concrete one so this could be a real problem. If I looked for the lowest powered unit I can find, I might be okay, but I'll either need to figure out some way actively of monitoring my battery voltage or turn the sensitivity so low that it wouldn't detect anything. This might end up as more of a pain than a help.

My alarm does have a glass breakage sensor, maybe if turned that way up it could "hear" the top being cut, or maybe not. If only there was some way of wiring the soft top itself to set off the alarm when it's cut...