THSCC Forums

OK, here's something that we have been talking about for years. If we had a wireless adapter to use on the finish beam of our timing system we could open up a lot of course design possibilities that cannot be done with the current wired range of our timing system. In fact, at Sanford we could start running courses all the way down the runway and stay off of the taxiway completely (for good reasons!).

This idea has been kicked around and there have been several ideas, but nothing has been talked about in one place. Now I want to get some traction behind this idea and have something operational if possible by the first event next year.

Whomever comes up with the system, buys the pieces (with club money), and gets it working and debugged will receive a FREE PASS for the 2004 Autocross season for your efforts!

Here are my thoughts on the requirements:

- Fully optional to use with the existing system (ie invisible to existing timer box, and not necessary)
- Utilizes the existing photoheads
- Receiver runs off of 12v power coming from the timer
- Transmitter runs off of a remote 12v car battery (solar and a rechargable battery would be even better)
- Remote power source will also need to supply power to the photohead
- Is not affected by typical RF interference (duh)
- Range of at least 3000 feet (5000 ft or 1 mile would be a better design point)
- Low power (won't drain the car battery during an event)
- Waterproof
- Durable
- Easy to set up (small / self contained)
- Easy to troubleshoot (blinking lights are g00d)

While I'm no electrical guru, I will describe the system we have now to the best of my knowledge. The JACircuits timer box runs off of 12v power. Two laser photoheads are run from the timer box and are provided with 12v power from the box on 4-wire cables. The lasers use reflectors for the beam. According to the JACircuits manual,

"The signal interface between the photoheads and the timer is the most common standard industrial interface, open collector - current sink. When the beam (pulse train) is being reflected to the receiver unit, the photohead acts as ground. When the beam is broken, the photohead output is an open circuit (which) allows an internal 5v signal to cause a trigger pulse."

That's all the information I have. Maybe our timer gurus will have more to add. I would prefer we pick up something nearly off-the-shelf that meets our needs, but I seem to remember that they are outrageously priced.

So who's got some ideas?

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Mike Whitney
whit32@gmail.com, 919-454-5445
V10, V8, V8t, I6, I6, V6, F4t, I4, I4, I4, I4, I2, 1, 1

Stop watch and radio would work . Are all my events free now since this was my idea.

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2006 Civic Si - #24 HS for 2015

2005 GMC Sierra
1991 318is Garage Ornament

Have you ever considered being an officer with Triad? Those guys would _love_ you.

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Mike Whitney
whit32@gmail.com, 919-454-5445
V10, V8, V8t, I6, I6, V6, F4t, I4, I4, I4, I4, I2, 1, 1

Anyone know how long this has been on JACircuits website?

"WIRELESS PHOTOHEADS!

The R&D department is STILL working on a way to do this. Initial studies show that there is a definite range - cost tradeoff. If long range is desired (greater than 1000 feet), than the solution is the wireless stuff used by the skiers and bike racers which is very expensive! Stay Tuned!"

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In need of car.

Here's something I just found to get some people thinking

http://www.aaaremotes.com/xr1midranrec.html
http://www.aaaremotes.com/xtmidrange.html

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Mike Whitney
whit32@gmail.com, 919-454-5445
V10, V8, V8t, I6, I6, V6, F4t, I4, I4, I4, I4, I2, 1, 1

Here's another (maybe better) one:

http://www.federalsignal-indust.com/def ... lookup=148
http://www.federalsignal-indust.com/def ... lookup=152

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Mike Whitney
whit32@gmail.com, 919-454-5445
V10, V8, V8t, I6, I6, V6, F4t, I4, I4, I4, I4, I2, 1, 1

Good idea, but don't be surprised if it doesn't happen early next year. I'm on a wireless project at work and the glitches we've run into are just plain rediculous, but hey, what can you expect working with ibm? hehe, I know many THSCC'ers work there!

Anyway, I don't have the electrical understanding to put something like this together, but I'll poke around. If I can help others look into this, let me know, I love to research stuff!

phil

That 3000 Ft may kill the project, especially with FCC stuff. I think you could get 1K though. Maybe have a two laptop system with a 802G connection.

The soluton Mike suggests would require a wireless transmitter that can be plugged into the laser head at the finish. It would send a signal to a receiver connected to the JAC box. The JAC box needs to think there is a wire there, just like now.

The missing piece of info to make this work is- what is the protocol being used between the photoheads and the JAC box? Is it RS-232? I don't know- maybe. If it's an RS-232 serial async connection, it would make life easier.

There are a number of RS-232 wireless transceivers, or transmitter- receiver pairs that are available. If you do a google search on RS-232 wireless, you will be presented with a ton of options.

So, really, that's what we need to know first- what is the protocol between the laser head and the JAC box?

I looked into this some awhile back and found some really solid RS-232 wireless black boxes that would work great- if we just could verify the protocol.

Garry (our timing guy) is our official interface to the JAC guys, so I think we need to either get him to ask JAC or get his permission for one of us to. Until we know the answer to that question we are dead in the water if we plan to keep our existing equipment.

I could ask that question next week if Garry is ok with it.

By the way, if the range isn't at least rated at 1 to 2 miles, it isn't worth bothering. We can string 1200' of cable. If we are going to do this, let's get enough capability to run from one end of a runway to the other. It must work over at least 1 mile range to meet our needs.

Miles Beam

Miles - the signal does not use a protocol. It is a simple high-low 5v signal as I described in the quote above.

Just to start some more bad ideas, what is the "sampling" rate of FRS? Couldn't a simple circuit be made to adapt a signal transmission to do through a $49 radio? Those things got some range!

Miles - let's see what other ideas people have first before you jump in.

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Mike Whitney
whit32@gmail.com, 919-454-5445
V10, V8, V8t, I6, I6, V6, F4t, I4, I4, I4, I4, I2, 1, 1

Which isn't hard to sample with some very tiny CPU based entity and convert to an RS-232 signal. If only I had the time...



Illegal. FRS is very clearly defined and this don't fit.

Personally, I think the easiest way to get something that *works* would be to use a small low power CPU device, like a PIC chip (or BASIC stamp, as they are called). Those are cheap so it would be easy to have a spare on hand. Convert signal to RS-232. Then buy one of the commercially available RS-232 wireless communication pairs (there are several and they aren't cheap, but they are industrial and thus should work well). Then you either hack the timing stuff to accept the signal via RS-232 (not sure how possible tihs is since I haven't seen that software, but it may be possible) -or- you simply have another PIC based box on the receiver side that reconverts back.

The PIC boxes wouldn't cost $50 each to build. What you would need is a fairly significant battery on the transmitter side, which you need to take into account for safety purposes (ie. a car battery just sitting around the finish could be problematic).


--Donnie

Well if it is a "simple 5v" signal, then couldn't you make a black box that converts that to RS-232 level. Then use some wireless RS-232 like Miles was talking about. Then make another black box that converts the RS-232 back to 5v. These black boxes would consist of 1-4$ worth of parts (ie RS232 chip, a few caps, voltage regulator). Just my $.02.

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2001 Honda S2000 - SOLD
2012 Boss 302
2003 BMW 330i

What about something like this http://www.aerocomm.com/OEM/AC4424.htm ?

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2004 Ranger Edge
2003 Buell XB9R
2004 Trek 4900
2004 Specialized Stumpjumper FSR Expert Disc
2004 Lemond Reno

Or with a power inverter we could run something like this http://www.aerocomm.com/Pkg/connexlink.htm

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2004 Ranger Edge
2003 Buell XB9R
2004 Trek 4900
2004 Specialized Stumpjumper FSR Expert Disc
2004 Lemond Reno

I know that we cannot go to a race track timing system with transponders in each car and we also cannot go to incar data acquisition systems which use some sort of "beacon" at key points on the track. However, is there any aspect of either of these technologies that might be applicable to our situation? I wonder what the odds are that the JAC's guys have missed any affordable solution?

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Dick Rasmussen

FS 50 2018 Mustang GT