You are looking at one of my latest project:

£50 is the starting price for a basic PCB layout plus postage.

Can be made as either a single lane or two lanes lap counter. Codes do differ a bit.

Options:
An additional £5 for each relay circuit.
(one per lane).
The additional piezo speaker is free (left optional as some ppl might not want to hear beeps constantly).
There is a dedicated terminal to run a 5V RGB LED strip (up to 10 ws2812b) to be programmed to requirement.
Sounds, screen content and behaviour can be customised (limited).

The board can also be reprogrammed by yourself using an FT232RL (a 6pin header is installed. FT232RL chip is not included).

What's included:
Assembled PCB with LCD screen (blue) and all the minimum requirement to run the lap counter.
x1 wired overhanging LED and underside track light sensor (×2 if 2 lanes setup).
PCB terminals.
Fully programmed micro-controller.

What else do you need:
A way to power the PCB such as:
Using the track power or external power supply (not included).
Recommended current: 10-20v, 1.5-2A. But have been able to test with a voltage as low as 7v (not recommended if running an LED strip)
An enclosure or make it part of the decor (a 3D printed enclosure and gantry are not yet available but will in the near future).
Install included overhanging LED and underside track sensor.
And finally, a potentiometer knob.

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Above: space available for a piezo speaker.
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above: relay circuits (not included)
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Above: terminal blocks. Note: a larger size than pictured will be installed.
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Below: single lane or two lanes feature a very simple menu allowing the user to setup laps.
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Below: single lane setup only, will display a total race time and set number of laps as opposed to a two lanes setup. Which will display driver's current position, last lap time, best lap and current lap.
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The RGB LED included will indicate track condition, when clocking a lap or best lap.

Only 19 copies can be built atm, each will differ depending on requirement.

Feel free to ask questions in the comment section below or message me directly for a quote.