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I've built two. They were a fun project. Cost was about $300 for each. One was a wired ethernet, the other used WiFi. We use the WiFi one on the 200m mark, and the wired one at the finish line. I'd say it took about 100 hours or so designing and building.

Basically I used a raspberry pi to perform the clock display logic and a virtual com port to send data from FinishLynx to the pi.

The clocks are made of 250 high intensity LEDs, organized as segmented strips in a ##:##.# fashion, and do a great job in bright sunlight.

I can post more info if anyone wants it.
Yes, I used 1/8" wood for box since it is a material I can work with. As we are in SoCal, our youth track season (March-June) rarely gets wet, but that would be an area of improvement. Paint can only protect so much.

On the first clock I made, I used a PC power supply - which does generate enough to heat that I needed to vent, but a fan attached to the grill on side takes care of that. For the second clock that runs on battery, passive venting is all I needed.

Here's a sketch up of the LED array use for each segment on the clock, composed of 7 LED's and 7 100-ohm resistors going into a 2N2222a transistor that is driven by 74HC595 shift register.

And here is a sketch up of the PI to a BiDirectional Level Shifter to the 74HC595 shift register.

(Sorry for the rotated images).
If you have the FinishLynx Network COM port plug-in, then you only need to program a network UDP socket receiver and then output to bang'ing the GPIO pins to light up the LED segments. I did mine in C/C++, but I imagine it can be done in Python too.

Data sent by finish lynx is sent as you'd expect - dependent on what *.lss script you used - I just made my own.

Now if you don't have the Lynx COM port plugin, then you can either buy it for $500 (I think that is what it cost), or you can do what I did and use an open-sourced COM0COM driver that creates a pair of virtual com ports. The way COM0COM works is all data received on one COM port of the pair is output to the other COM port of the pair and vice-a-versa.

You configure FinishLynx scoreboard to use one of the COM port you created, and then on the other com port you have a program that reads that COM port and forwards all data out on an UDP port - which gets sent on on the network to your PI.
Thanks for your prompt and detailed reply
I have a Daktronics timing display and a Gill ultrasonic wind gauge
Both communicate with the FinishLynx PC using a USB-serial cable linked to a serial-bluetooth adapter.
The link works very well

Although it would be nice to have a'cheaper' timing display (clock), I am thinking now of a display which shows the output from the wind gauge automatically
These are available from Gill but are very expensive

The wind gauge has two DB9 (RS232) ports and the device outputs a series of bytes (about 18 bytes - only the middle 5 bytes carry the data) when it has acquired one set of data (race completed)
One port interacts with the FinishLynx PC and the other is (at the moment) unused
I hope to use the unused port to send data to the (planned) display

This would need only two digits with a permanently lit decimal point in between + a few LED for the '-' symbol where appropriate
This would be a lot easier to build

This display can be close to the wind gauge so can be linked with a physical cable

I know that I can add a RS232 module to the Raspberry - can that be used as an input, then transmitting that data to the LED segments?

Thanks for your help?
Sorry, I'm not familiar with the BASIC Stamp Micro-controller. However, you should be able to diagnose where your problem is quite easily. With your breadboard, jump the +V to to the base (B) of your transistor. Your LED controlled by the transistor should illuminate and stay illuminated. If this is so, your flashing problem is caused by the device that signals the transistor, (I'm guessing is your BASIC Stamp).

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