[chrissimms]

Looking for a type of sensor or something to imbed into the track to send a signal to a counter or sound card to " go off " when a car passes

[woodcote]

Hi Chris and welcome  

What track system are you using? There are plenty of options - also depends on what lap counting software you are planning to use.

For solo running, I find smart phone apps like LapTrax (Android) and LapTracker-Auto Timer (Apple) are really handy. They use the camera on the phone to sense movement in a defined area. They do need some careful setting up and calibration, but work a treat.

[chrissimms]

1/24 track and cars
Wanting to trigger a sound as the cars pass the sensors

[Scuderia_Turini]

Hello Chris,

If you have some basic very basic electronics skills and just want a simple "beep" then you could use one these sensors linked to a piezo-sounder.  A 5volt power sourcewould be needed - a mobile phone charger might just about do it. If you want something like a car engine then there are "sound chips" that you can record your own sound for playback when triggered by the sensor. Sensor would go at the side of the track pointing across it and adjusting the range could cover both lanes or just the nearest one. I had difficulty that these sensors would not sense an all-black car but worked fine with other colours and combinations (ie all-black with a bit of white tape stuck on the side).

This kind of thing has worked for me previously for triggering lap recorders, but its up to you to decide if you have the appropriate skills.

Leo

Ebay link for sensors

Ebay link for piezo sounders