Track timer made from digital watch

Hi… hope you have a nice day,

The idea is looking for fastest car from all my collection, not to much but I have to find the fastest car for real race with my community here, In Bandung, Indonesia.

This is the race

And this is the timer I made. Not a Bom ya...

The basic tutorial from

-          makezine.com/projects/sensor-triggered-toy-race-car-timer/

But I can’t find the electrical part from nearest shop here. So just take the logic and find suitable from my junk stuff.

What we need is

-          Stopwatch, i find from my junk digital watch

-          The sensor  I change with some wire for connector.

-          Reset Button, take from old electric part.

-          Electric wire

The Logic is :

-          Pull out the Start/Stop and Reset from Stopwatch/Digital watch. The Stuffs have similar function is have stopwatch timer. So just connect Start/Stop and Reset button contact to the electric wire with solder or something else. Test It.

-          In my case, wiring is like with the tutorial. From the watch have 3 wire, start/stop, reset and from battery case.

-          passing about resistor, capacitor sensor, ic in the tutorial.

-          Connect the reset wire to the battery wire trough the button take from old part. Test it.

-          Start/Stop Wire connect to battery wire to test it. If success make it parallel for start gate and finish gate. In my case I used power plug from unused computer power supply and phone wire connector to make it portable.

-          Make start gate and finish, on my creation I use plywood for Start gate and replica finish gate from PVC pipe.

-          For Start and finish gate contact, I use wire from spring. Connect with the electric wire.

 This is The Result :