Poor man's throttle/brake LED's for camcorder review

[ZOA NOM]

I finally managed to get on the track at Thunderhill on March 31st, and had planned ahead by fabricating and installing a camcorder mount that turned out to be incredibly stable. With a wide-angle attachment for the Mini DV camcorder, I was stoked for the opportunity to review my runs, and being able to see from the shifter to the top of the windshield. One of the first comments by my instructor was to add a brake light in the camera's field of view if possible. I wanted to minimize the cutting and drilling in an otherwise stock Carrera, so I did the following:

Using a normally-open magnetic switch, and a magnet mounted to the backside of the gas pedal, the switch closes when the pedal moves away from it, lighting the throttle LED.



The LED's were mounted inside (behind) the ashtray. The brake LED is connected to the brake pressure switch on the Master Cylinder.

With the ashtray installed, everything disappears.



With it out, the LED's shine directly at the camera mount between the seats. Works like a charm, and it can all be removed without any harm to the car.

[Jack Olsen]

Cool! I'm going to do something similar -- but I think I keep getting too ambitious (multiple LED's for throttle position).

[RarlyL8]

That's great!

[ZOA NOM]

Yeah, Jack, I've got it bad too. I'm thinking about adding another (normally open) magnetic switch somewhere near full throttle, and hooking it to the brake LED, which would result in both LED's on at WOT. The only other time they would both be on is when I heel/toe, but it would be obvious in the video which I was doing. I have to be careful that my car doesn't start looking like a Philipino Jeepney bus, but the price and simplicity was right.

Here's a link to one of my laps at my first track day. It was at Thunderhill in the rain. My instructor was Mike Mitchell, who had nice things to say about you, Jack, and was an outstanding teacher.

[Don Plumley]

Great idea!

[Jim Williams]

ZOANAS,

Great idea with the throttle/brake LEDs. Now come up with an easy way to implement a set of LEDs that show the gear selected! You could go with only 2nd, 3rd, and maybe 4th, as most gears selected on the track don't include 1st and 5th, and if so, they shouldn't be that hard to figure out........

I couldn't see my speedo or tach in my video setup for my SC, and came up with a solution for that, consisting of an LED pair of these, mounted on the dash under the radio using some of those super strong rare earth magnets. They got power from a connector I mounted in the hole the clock normally sits in.



Here's a video frame from Road Atlanta, the speedo is on the left. The tach is out of sync in this frame with the camera frame rate.


When the video is replayed, the zeros are not apparent. Notice how the stock speedo is obscured by my hand, and the stock tach is underexposed and can't be read. (My ashtray space is filled with an A/C vent I built.)

The SC has been sold, and I can't figure out how to adapt the LED gauges to the dash of my 996, which now goes to DEs in place of the SC.

[ZOA NOM]

Sweet, I knew it was a slippery slope. With my wide angle lens. I can see my shifter, so I can see the gear I'm in, along with my hand as it shifts. I wouldn't mind the tach and speedo, tho.

[vash]

i am proud to say (or type), "i know ZOANAS"!!! very slick

our LAMBDA SC's have a microswitch that tells the car when the throttle is on. i wonder if a used one can be fab up for the carrera. then all the business stuff would be in the engine compartment. i am mentally putting a to-do list together for you rick.

[Jack Olsen]

Jim, that's awesome. Any chance of you putting together the basic plans for something like what you did? I've been looking for a way to display that information for a long time, but I'm challenges in the EE-skills department.

[RarlyL8]

All these electrical track monitoring gizmos are neat and all but it's time to get down to the important stuff. What is BAP?

[vash]

BAP is some yahoo group we started. it means "bay area pelicans" for us in the san francisco area.

we talk alot of trash but never politics or religion. and we set up group drives, and more importantly we call out for pcar mechanical help on it. kinda like the bat signal.

[emcon5]

Originally posted by vash
our LAMBDA SC's have a microswitch that tells the car when the throttle is on.

That is what I did on my Rabbit race car. Used the CIS micro switch for the full throttle light, and tapped into the brake light circuit for the brake light. We made a sun shade from the cap from a spray paint can.

Video here. (13MB WMV file)

Zonas, am I reading that right, that your light comes on when you are on the throttle at all, rather than full throttle?

Tom

[ZOA NOM]

Yes, the light comes on as soon as I get on the throttle. Actually, the magnet on the gas pedal keeps the light off when the pedal is at rest. I'm planning to add an LED for WOT, with a second magnetic switch mounted on the AC duct closer to the floorboard.


Here's a clip

I also added a small external microphone on a long wire that I can move around the cabin to find the best sound.

[Mahler9th]

You can also tap into the existing brake light circuit to accomplish this. The switch in my race car is a stock normally-open switch and it is easy to study the schematic and tap into the circuit to get another 12vdc available for a dash-mounted brake light. For WOT, I have thought about a number of approaches. My existing throttle body uses a 944 cc/clutch swith. My new thottle body will use a Radio Shack micro switch for WOT.

Be aware that it may be important to choose lights of sufficient brightness and size so you can really see them in the camera FOV. There are a number of variables-- just don't go too small or too dim.

I also have a Datatool sequential shift light mounted above my tach (aboput $90) and it helps when I race. Cannot see it in the FOV though. Datatool also make a gear indicator light for motorcycles... but I don't think that type of thing would be too valuable sine I only use 3-5 at most tracks.

Of course as time goes on, the costs of good onboard data acq. systems is coming down. AIM kart and car units are getting really popular... when you add up all of the time to rig these lights up and the typical hotlap timer... things start getting reallly comparable.

- Mike
EXIT SPEED

[ZOA NOM]

Home base! HOME BASE!!!

[JohnJL]

How about this...use an air/fuel ration meter like this one...




...hooked up to a radioshack potentiometer linked to your throttle cable or pedal assembly. Give it 5V reference voltage and calibrate it...and you've got a very good/easily visible throttle meter...

[304065]

While it's easier to review the tape and see where you are on and off the brakes and gas, another approach is to feed those inputs into a data logger with analog inputs, like the DL-1 or even the Auxbox for the LM-1 Air-Fuel logger. There is software available that will overlay the data log onto the video itself, and presto, you've got in-car analysis along with actual lap data so you can SEE where altering the braking point or picking up the throttle earlier made a difference.

[ZOA NOM]

Yeah, but the title of the thread was "Poor man's throttle/brake LED's for camcorder review". I did everything for under $10, without drilling, cutting, or modifying the car. If it wasn't my daily driver, I'd be looking at more sophisticated methods, for sure.

[JohnJL]

Not too rich tho...Digital A/F meter from JWhitney ~45, Radioshack potentiometer ~5, a few transistors, ~1, a hose clamp around the meter to hold it to something on the dash ~1....

http://www.jcwhitney.com/autoparts/Product/tf-Browse/s-10101/Pr-p_Product.CATENTRY_ID:2008854/showCustom-0/p-2008854/N-111+10201+600002105/c-10101

[Jim Williams]

Originally posted by Jack Olsen
Jim, that's awesome. Any chance of you putting together the basic plans for something like what you did? I've been looking for a way to display that information for a long time, but I'm challenges in the EE-skills department.

The gauges are from JC Witney, I have numbers if anyone is interested. I might say this is not a "poor man's solution". I guess it depends how bad you want this info displayed on the video.......

Here is some more info:

I replaced the car's clock with an air/fuel ratio meter, also from Whitney. I offset the gauge to make room for a small connector. The A/F gauge was more or less permanently mounted, and the speedo and tach gauges hooked in to the A/F gauge at the connector so the gauges could be easily removed using the magnetic mount.

The electrical connections were via spade lugs to the behind the dash connections so the whole thing could be removed when the car was sold with no damages to the wiring.

I have a wiring diagram drawn out in pencil which is really too light to make a photo, but I would be glad to redo it and post it if anyone wants. (Jack?)

Photos of the "stick on the dash" unit: