My Banked Oval Track and Lap Counter

[Mr.Craig]

I am almost done with my new banked oval track.
There are 8 turn sections(10 foot diameter) and 10 straight sections (4 foot long) that can be arranged as 18x22 to 10x30.

The cars (BRP SC-18's) are controlled with arcade style steering wheels and t-handle shifters for throttle.

I still need to work on the walls, I don't like the way they came out.

I wanted a lap counter for the eight cars but could not find one that is affordably priced without using flags, so I built my own. It uses infrared transponders in each car and a timing bridge over the Start/Finish line with eight infrared receivers. I tested it outside over the weekend and it works very well. I have a few tweaks to do to the code(it is run by a microcontroller), but it didn't miss a lap in four hours of testing.

This is a picture of the track. I thought I took more (and better) pictures but can't find them now. I will post them when I do.

[Mr.Craig]

another pic

[Mr.Craig]

A driving console

[Stridex]

Instructions on the steering wheel console would be awesome. I've been looking all over for info and came up nada. I was thinking about buying those cheap steering wheels for PS2 or XBOX and trying to convert it.

P.S. AWESOME TRACK!

[TeamBonzer]

NIce track Dude.

Interested in your timing devices. How big are the IR transponders, how much do they cost, would the fit in a 1/64th scale?, lots of questions I know, but really interested in a counting/timing system for multiple cars at a good price.

Cheers

TB

[Mr.Craig]

Stridex,
I have to look back and see if I can find where I got the parts.

Teambonzer,
I have attached a photo of one of the prototypes.
It is sitting on is a standard size Futaba servo in a BRP SC-18.

It could be made smaller using surface mount and a single LED can be mounted on the body and attached to the circuit with a two pin connector.

I had not intended to sell these, but the reason I ended up building it was because there is nothing available for multiple cars.
I don't know what your idea of a "good price" is. Off the top of my head I would guess I could sell a commercial quality version of this for somewhere in the 600 - 650 dollar range. If there is sufficient interest I can come up with a more accurate number or build a couple of systems to start out with.

[Mr.Craig]

TeamBonzer,
I checked out your website and your bonzermats.

My plate is pretty full now, but in the near future I will have some time to work out something for a small track like you make that would be a lot less expensive if there is enough interest.

How many cars do you run at a time and how fast do the go?

How wide is the track where the Start/finish line will be?

How many volts do they run on?

Would you just want number of laps or do you want actual lap times and if so, how precise?(tenths or hundredths of a second)

[TeamBonzer]

Hi MC

track width is about 15cm (6").
Race upto 6 cars at once
Would like the full monty in terms of timing and counting features
The cars are only 6cm long and run off 1.2v NiMH/NiCd 60-200mAh
Car speed is between 3 and 10mph

Cheers

TB

[Mr.Craig]

TeamBonzer,
I'll keep it in the back of my head, perhaps I can do something like this in the future.

I assume you want an lcd display for standalone operation.
How many laps can these cars pull of in a charge?

Only 1 volt available in the car will be a challange.

[TeamBonzer]

These cars can easily do 50 laps (30 minutes run time from a 3-5 min charge)

My prefered solution would be passive RFID, although I understand that one of the car manufactures have a system that uses the leaked RF from each car to clock them.

I liked your solution because it is the first I have seen that could deliver a low cost system. The PCB's on the car support LED headlights etc and I figured that the IR wouldn't be much different.

The software/circuits for timing isn't a problem, lots about, just need a cheap and simple way to clock each vehicle.

Cheers

TB

[Racer9]

Looks awesome! Keep up the good work!

[Mr.Craig]

The lap counter is still in developement.
Previously I wrote that it didn't miss a lap in 4 hours of testing. However, I tested further by putting more than one transmitter on each car to simulate very close racing. It still didn't miss any laps, but certain combinations of two would register a third car that wasn't there. As unlikely as this scenario may be in real racing, It is unacceptable to me.

I am currently rewriting the code and using a bi-directional link that will eliminate any errors.

I don't own a 1/64th car, I will have to get a few to start on a system for them when the time comes (I have a lot going on already). The low voltage and small size will be a challenge and it probably wouldn't end up much cheaper than the bigger system, so it may still be priced outside the range of these small cars.

I don't have a final parts list yet. The transponders and the host controller are all running Atmel microcontrollers(very small computers) that are useless without the software that get programmed into them. The infrared link is now done with irda transceivers.

There seems to be some interest in the system, I will post any progress made as it happens.

[codesuidae]

Howdy, thats a nice looking track you've got there Mr.C. Of what material is that track surface composed?

I've recently been considering developing a transponder system similar to yours, but other projects have taken priority.

The ZZSE uses a 2.4v battery, and I think pretty much all of these cars use a voltage boost circuit to operate the logic bits of the PCB at ~3v.

Tapping in to that 3v supply might be asking too much for many people, since it requires a bit of soldering on their baby.

Here are my questions:

What model AVR are you using?
Is the timing too critical to use the internal osc. on e.g. the ATtiny?
What is/will be the signaling method (I don't know much about IrDA so I don't know what using it implies about the data transmission)?
Which IrDA tranciever will you be using?

Do you think that rather than switching to more complex transponders it would be worthwhile to implement Goertzel or DFFT frequency discrimination in the decoder?

In what language/ are you developing the software?
Will the software be open source?

What features does the decoder provide?
Does the decoder maintain an internal tick count since the start of the race?
Will a serial link to a computer to run timing software be available?

I'm a windows software developer and AVR hobbiest with experience writing timing/scoring applications using AMB and Westhold RF transponder technology. I'm currently working on an AVR project to replace the drive and steering handling in the ZZSE in order to provide better proportional control, fix the models with broken steering, and provide additional control channels for in-car devices (lights, turbo, etc), and to provide a customizable platform for experimentation.

[Mr.Craig]

>>What model AVR are you using?

?The host is running a mega8535, the transponders use 90s2323's

>>Is the timing too critical to use the internal osc. on e.g. the ATtiny?

In a word, yes. I am using crystals. The internal oscillators will vary with temp.

>>What is/will be the signaling method ?
It is not finished yet. I am developing my own protocol and just using the infrared for the link

>>Which IrDA tranciever will you be using?
Right now hsdl-1001, probably something more compact in the final version.

>>In what language/ are you developing the software?
AVR ASM

>>Will the software be open source?
No, probably not.

>>What features does the decoder provide?
It ouputs the car # to a serial port when it passes.
There is an adjustable delay timer between individual car events(eg. It won't repeat car #1 until it has been away from the bridge for .25 to 4 seconds)

>>Does the decoder maintain an internal tick count since the start of the race?
It can. Right now it outputs a signal at 3 mins to signal race over.

>>Will a serial link to a computer to run timing software be available?
Yes, thats actually how I use it now with RClapDog software.
Also in the works is a scoreboard with large lcd digits to track laps. The lap counter is being built for my rental track.
I need to find the serial output format for AMB systems to allow broader software compatability.

[codesuidae]

I don't know. At the time the hardware solution was pretty flawless and I was busy developing the software, so I never got around to poking into the hardware.