LOL...timing gun?
 

OK, in the old days, you could put some chalk on your car's timing pully, point a strobing timing light at it and determine the timing of your engine. Now days, I can't even find the spark plugs. Anyway, what if we put a little white mark on our Zips wheels, and with the timing gun, could we check wheel RPM's or something? Sorry, must be the beer.

Also, I thought someone was going to rig up a motherboard fan RMP header so that we could build a Zip Dyno? Well...get busy dammit!

Hum. Also use to do that to check tuntables and Reel to Reel recorders.

Re: LOL...timing gun?
 

Yup must be the beer steve! HEHE!! I just don't see how you can rig a timing gun used to measure the degress at which the crankshaft is at when cylinder 1 fires to measure a electric motor RMP! :)

I have been looking into a simple circuit using an old ball mouse, (YES mice weren't always optical kids) One could take the IR emitter and receiver and put a back tire between the two, take advantage of the missing piece on ZZ tires where the hubcap goes to trigger the receiver. or simple attach the encoder wheel to a tire somehow, covering all of the holes but one.

The problem come with interfacing to a PC.

www.boondog.com/tutorials/irled/ir.html

wish this guy would've finish his project :(

I'll keep searching the we for something we can use!

Hmm, I've got a digital tach at work. I'm gonna have to try this...

Could rip the sensor from a ClueCat. Since its a bounce version could point it at a wheel.

If I can get past some jobs for clients and finish the ZZ receiver circut diagram could work up something. The catch is do you apply a load when measuring?

clue cat thats funny i didnt think they had a clue of anything????i just picked up like ten of em at goodwill for a buck seems no one wants em

Re: Re: LOL...timing gun?
 

haha I was just trying to get your minds working, things have been kinda dull here lately.

Re: Re: Re: LOL...timing gun?
 

:D It worked!!!
I was thinking of ctshaynes idea of using a digital tach as well, I have one that reads both 2 and 4 cycle engines by using the same principle as the timing gun, in the 4 cycle setting it reads everytime the sparkplug fires and since there's 2 revolutions on a 4 cycle engine it must divide that by two to give the correct RPM, on the 2 cycle setting it just takes the number as is for the calculation (1 spark per revolution)
SO the trick is to full the tach into thinking it is reading a car ignition, one can rig an IR emitter and receiver across the rear tire and hook that to a coil then one could clamp the tack on a sparkplug wire coming out of the coil...Everytime the wheel spins pass the gap it would trigger the IR receiver that would trigger the coil that will trigger the tack......The only question remaining is what to do with the couple of thousand volts sparking out of the wire.....It'll make a nice lightning display?!?

There has to be a cleaner way ;)

Maybe this will help.

Got the latest catalog from All Electronics and in the back they have the following:

Wheel w/Hall-Effect Sensor
2 for 1.00
Hall efect sensor with a detacable rubber wheel. Basically two pulses per revolution! Wheel diameter is 0.53 mounted on metal bracket.

CAT # EX-202.

web site:

www.allelectronics.com

Happy Hacking! :)

PS they also had a bar scanner but that another topic...

Nice,

but we are still missing the rest of the circuit :(

there has to be a simple way of doing this. What about using the "simple track timer"*, and set the triggers a known distance appart one would get the time required to travel that distance and calculate average wheel RPM. Assuming we are not spinning the tires in place which is unlikely.

This I think would be a more usefull number than getting RPM at a teststand. were there's no car weight drag etc.

by moving the sensors up and down the track or setting up all 4 sensors this way on the drag strip one could get a clear picture of what the car is doing at different points of the track...Any comments???

*search for "lap timer" for more info on it, But in a nutshell one can measure the time it takes the car to travel on a strait line using this track timer and mirrors.

Either feed the on-off signal to a Freq counter, Computer or a embeded cpu acting like a counter should work.

The simplest and best wasy is kind of what you were describing.

Simply do it with a measured distance and a stop watch be off about 1/10 of a second but if the cource is long enough should work.

Simply measure a distance. You want a A, B, and C points on a level surface. A is where you place the car. B is where you hit the start on the watch and C is where you stop the watch. B & C are the exact measured area.

So lets say it 2 feet from B to C. Dont really care about A just a starting point for the car. lets it get up to max speed. It crossing B then C that is the key. Like the Saltlake speed runs.

So if it takes 1 second then its 2 fps times what ever scaller you want to use to make it big size.

The Vascar from the late 1960's was a solid mecanical device that read out in MPH and use a human as the input sensor. All you did was pick two points over 1/2 mile I think, drive it while loging it in the box. Sit along side where you can see both point. Hit start then stop and it would read out the MPH.

Oh the time it takes to go from "eye", "to though", to "hit button" is average out by the two hits. Simple huh. And can be done anywhere. All it cost is a cheap stopwatch and a good ruller.

I Remember Steve Circa did somthing like this with a bottle rocket in his mag.

I agree about the Dyno. All have some type of load they can place on the car in test. The catch is trying to calibrate a small one for these cars. Hum... Just though of something.. :) Need to do some research! Tnks! :)

Well the beauty of the lap timer is that it will do this for you at less that $10, All you need is
PC...
software...
parallel cable...
phototransistor from Radio shack ~$1.50
LAser pointer ~$5.00
two small mirrors

The software was originally designed to track 4 lanes on slot cars, so you get 4 input lines, the software is really nice. I have to give credit to Steve for finding this baby!!!
Do a search on the forum for "lap timer" his thread is called that.

I was able to bring the cost WAY down by ordering a cheap laser pointer from wholesaleforeveryone they go as cheap as $3.00 + $1.50 shipping. I will also use any spare powersupply I can find at home with a simple homemade voltage regulator circuit on it but you can use the batteries until they last!

Since the timer for each input starts by breaking the beam and stops by breaking the beam again, One lap, the trick for a drag strip setup is to set the laser at the starting line, and have the beam cross the track into a mirror that will take the beam along the side of the track to another mirror that will make the beam cross the track again and into the detector. this is very simple to do and you can vary the distance and move the setup anyware along the track to calculate speed and average rpm at any point. If you want to get fancy you can setup all 4 detectors on the track so you get 4 readings in one run.

SO that way we take human error out of the equation!!!