Hi, this is Wayne again with a topic “Sensor-Triggered Toy Race Car Timer”.
Racing toy cars is a lot of fun to make it even better. I built a race timer that automatically records the finish time of each race. Here’S how to make it start by finding a standard stopwatch open up the housing. So you can access the internal circuit board, find the contacts on the board for each of the buttons solder, a small extension wire onto the start/stop button, and the reset button then remove the battery and solder one more wire onto the positive terminal of the battery pack. Next, I cut a small slot in the side of the housing that I could run the wires through.
You can now reassemble the stopwatch these wires will. Let us activate the stopwatch remotely, and this is the control circuit that I designed for this project. It uses two photo resistors to sense the cars moving by when a car drives over either sensor. It activates a 555 timer IC that is connected to the wires from the stopwatch. This will start and stop the clock. First, I prototype the circuit on a breadboard. When you cover up one sensor, the timer should start when you cover up the other sensor, the timer should stop. You may have to use some trial and error to select components that are appropriate for your lighting conditions. Once the circuit was working properly, I soldered the parts onto a piece of perfboard. The light sensors were connected to the board with a pair of long extension wires. This will allow them to be mounted to the track.
The light sensors need to be flush with the top of the track so that they won’t hit the cars so take a drill bit. That’S the same diameter as the sensor and drill a small recess in the top of the track, then drill two smaller holes for the leads of the sensor fit the sensor in place and connect the wires from the circuit board do this at both the starting line And the finish line of the track: when a car rolls over the sensor at the starting line, it will start the timer when the car rolls over the sensor at the finish line, it will stop the timer. There are a lot of potential applications for this kind of system, so try it out and have fun thanks for watching and check back next week for more DIY hacks and how to’s you you .