Parts are taking longer than expected to arrive... So far, I have received the microchips from Howard, I have my PCB Boards and one part that was from Digikey. I'm waiting for all the other parts from mouser electronics, but they have a few backorder, and some that, from what I understand, will not become available soon.. so I'll have to find some alternatives on a few of them.

UPDATE (FEB 6, 2015): I have received the parts yesterday. Will start building soon. Only thing, 3 little parts are backorder and will only be in stock by mid-May.
Unless someone would have alternatives on those parts, I'll only be able to post results by then. Here are the parts that I need (from Mouser Electronics)
-C5 Capacitor (Mouser stock number: 810-FK14X7R1H105K)
-R2 Resistor (Mouser stock number: 270-100-RC)
-R1 Resistor (Mouser stock number: 270-75-RC)

And for Loop Amp
-C7 Capacitor (Mouser stock number: 140-50N2-820J-RC)

You can use Mouser's search function to find functionally equivalent parts. Most of the specs and data sheets are on the web site. (This is also true for many other distributors.)

Here are some I located:

C5: http://www.mouser.com/ProductDetail/...D5En8Gfw%3d%3d

R2: http://www.mouser.com/ProductDetail/...KKw5tKQVBeM%3d

R1: http://www.mouser.com/ProductDetail/...TGJwQzbOheg%3d

C7: http://www.mouser.com/ProductDetail/...w3TlrUEbbog%3d

Thanks Howard! I tried with the search, but, as I explained, i'm not electronic engineer, so wasn't sure if they would be compatible! Thanks again!!!

hello all .. who is also from Germany here in the round ? who can give me help? thank

(hallo ihr.. ist auch wer aus deutschland hier in der runde? der mir hilfe geben kann? danke euch!!!)

Quote:
Originally Posted by garycapetown View Post
Thanks for your reply maeg,
I know that the transponders work with AMB as well.
How long have you made your loop?
Our track is 10m wide, so the loop wire will have to be 20m long.
Howard, Would the amplifier and decoder be able to work on such a long loop?
Is anyone already using the system sucsessfully with such a long loop?

No, it's too long. Our is 7.5m wide and we have problems without changing amplifier capacity.
maeg is offline Report Post

Hi... it has been a long time since I posted the above.... and would like to know if a new loop amplifier has been designed for a 10m loop.
Or if anyone knows of an amplifier that can do a 10m loop, that can basically stretch across a 10m wide tar road.

We finally have our decoder built. Next step is to build the loop amp and we will run a test

Hope everything will work as its supposed to!!

That looks great! Who manufactured the PC board?

Had them made by Osh Park. They are a community PCB board order. 2 layer boards are 5$ per square inches, and 4 layer are 10$ per square inch, and you get 3 copies of your board (no extra charge) plus, its free shipping!

Need to wait approx 5-6 weeks to get them, but for the price, can't complain!

Hello,

I was thinking to try to use this project to make an lap timing system for motocross.
We have a small structure with a track, actualy all is made by hand.

Does you thinks that the signal will be ok, with a bigger loop ( track is 4m large ) and in the terrain, the distance to the transponder will be 1m at maximum.

I must add and accu to the transponder as we do not have battery on MX bike.

Yves

Achieving operation at 1m separation between the loop and transponder would require at least a new loop amplifier design.

Also, the system is limited to 10 transponders running simultaneously. I believe most motocross races have far more competitors on track at the same time.

Yes, we have more competitors, normally the gate is for a max a 40 riders.

I have some old ATiny chip that are sleeping in a bag... I will try ton make a transponder to test. Some friend are Harm Radio amatory, this will be good for the amplifier of the loop.

the big part will be the decoder to build and transpose the software to CPU board like an ArduinoYun or a PCduino witch have Ethernet on board.

I use, for an humidity sensor i have developed last year witch make a mesure every ms in the die casting vacuum pipe, a PCDuino3 and have display, measurement, mysql database for the saving of the sample on a ssd and emulation of the Siemens Profinet protocol.

I have access on the track and the loop so, the job is staring.

Yves

Well... we finally have our system built. PC reads the decoder, and we get a constant 1.21 volts at the loop wire. However we are not able to pick up the transponder (tried with a mylap hybrid)

We think that, problem could be at the loop wire itself. Wire we used has some sort of shielding in it. we will have to try it again this weekend.

Any advise here Howard? anything else we should test/check ?

Thanks

The loop wire should not be shielded. I recommend normal 18AWG stranded wire.

Use an oscilloscope to trace the signal through the loop amplifier. It's a simple circuit, so that shouldn't take long to do.

We have changed the wire, and IT WORKS !!!