This is the second one of these I've built from plans I found here. The first one has been in use several times a week for over a year with no problems so I went with it again for the new track. If you've never used an Arduino. start here by downloading the Arduino IDE. I'm using version 1.0.5 but I had a problem with it. You have to go into the libraries folder and either delete or move the RobotControl and RobotMotor files out of that folder. Once that's done you can copy and paste the provided sketch into the IDE, verify it, and upload it into your Uno. You can configure this timer for one to six lanes, just alter the line in the sketch to match your track. The pics here show a six lane timer. You can add over the track displays if you want, I chose not to since this is only a test track and the times are recorded in my log automatically.
I chose to buy the pre-etched circuit board for this one, it did make the assembly easier. I had some components left over from the last build or I would have opted for the board and base components package he sells. The board comes bare, this pic shows it with some of the parts set in place to be soldered.
I soldered in wires in place of the status LED and the timer reset button so I could mount those two items through the lid of the project case. Here it is with the pin headers and other parts soldered in.
I soldered two rows of male pin headers to the underside also. These are what connect the board to the Arduino.
I mounted the status LED and the timer reset switch through the lid for easy access. The chrome bezels for the LEDs are made for two pin LEDs, so to mount the four pin multicolor LED I had to poke two more holes through the rubber mount making sure to keep all the pins separated.
It's done far enough now to upload the sketch and test it on the breadboard
It works! I left the sketch configured for one lane since I only had one sensor on the breadboard.
I cut a hole for the USB cable to plug in to the Arduino and mounted the control in the box on some short standoffs.
Once the wires pass through the box, it would be hard to identify what goes where so I marked both ends.
Now it's getting crowded in the box. Some of the wires pass through the back of the box and the rest go through the lid to a pair of jacks.
This jack connects to the start gate control box via a cable. I chose to use cat5 cable but you could use Molex connectors, Weatherpacks, or hardwire it if you want.
I needed two more jacks to run to the external sensors so this.......
becomes this:
I brazed together some 1" 6061 square tube to mount everthing
And mounted the control box to the finish line
I put together another board for the start box for the relay that controls the gate solenoid
The lid of the start box has a manual release button, a jack for a remote hand held button, and a jack for the 24v transformer that powers the solenoid. The two Molex connectors run to the gate switch and the gate release solenoid.
Every sensor bracket gets a jack so I can connect them together. I numbered everything as I went to keep it straight.
After connecting everything up, I was able to test all the sensors for the first time on the bench.
You also have the option of a large display if you want
All done and ready to mount to the track!
I mounted some of the sensors one foot apart, so I made this tool to calibrate them all the same. It's exactly 12" from the far end of the tool to the near end of the notch.
I use it like this and just keep moving one sensor until the pair register the same time when you slide the tool at even a slow speed.
I kept at it until it would repeat.....PITA but now I can compare times from pair to pair with a degree of certainty. I had the other sensors masked in the program so that's why they're showing the max time.
That's all there is to it!
I chose to buy the pre-etched circuit board for this one, it did make the assembly easier. I had some components left over from the last build or I would have opted for the board and base components package he sells. The board comes bare, this pic shows it with some of the parts set in place to be soldered.
It's done far enough now to upload the sketch and test it on the breadboard
It works! I left the sketch configured for one lane since I only had one sensor on the breadboard.
After connecting everything up, I was able to test all the sensors for the first time on the bench.
You also have the option of a large display if you want
All done and ready to mount to the track!
That's all there is to it!
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