DIY Arduino-based timer

[bracketracer]

Really, if you can solder and know how to determine an anode from a cathode you could build this out fairly easily. I had no experience with Arduinos when I built the first one. This second one was more complicated but mostly because I wanted to make aluminum timer towers so it would look cool. The first one I built has wood towers and they were easier to build.

 

[mifd118]

hi, i am wondering what a setup like this costs. we are a small troop and this is our first derby. we have a two lane track and dont really see the need at this time of a costly and complicated timing system. just a way to determine the winner for close finishes is all we need.

 

[TRE]

I think about 100.00 for the parts

 

[Kinser Racing]

hi, i am wondering what a setup like this costs. we are a small troop and this is our first derby. we have a two lane track and dont really see the need at this time of a costly and complicated timing system. just a way to determine the winner for close finishes is all we need.

You can always do a rerun if you cant determine the winner. Most of us want a precise system. Ours measure down to the 10,000th of a second. /images/boards/smilies/smile.gif

 

[Kinser Racing]

Honestly, with it being everyone's first derby, everyone will be all over the place. The chance of it being really close is very slim. The fact that you're here means your kid will be the winner.

 

[mifd118]

thanks very much for the replies. $100 seems a bit much for us and the re runs for a close finish would be ok. we bought the boys some car kits for $3.50 each, plastic wheels, nails and block of wood. we figured the dads could nail on the wheels for the smaller boys but thats about it.

 

[bracketracer]

hi, i am wondering what a setup like this costs. we are a small troop and this is our first derby. we have a two lane track and dont really see the need at this time of a costly and complicated timing system. just a way to determine the winner for close finishes is all we need.

You can always do a rerun if you cant determine the winner. Most of us want a precise system. Ours measure down to the 10,000th of a second. /images/boards/smilies/smile.gif

Uh Kinser, the system described here measures down past 1/10,000 sec also.

mifd118, if you already have a laptop with a usb port to run it, skip the electric gate release and the over-the-track displays, and you could build out a two lane setup for under $100. A genuine UNO cost about $27 online, you could get a clone UNO for around $17 or less, the pre-made PCB shield kit is $23 right now, you'd need to get the LED's, IR detectors, and a couple resistors at Radio Shack-even if you buy the chrome holders you'll be under $20 there for your two lane track. Little bit of wire and a start switch (under $5) and you're in business. You can use any material to build the tower to hold the sensors, look here for some ideas. You can plug in a larger external monitor to display the times to the crowd, this timer will also work with the very popular Grand Prix Race Manager software if you want to use it to run your race.

 

[bracketracer]

Since you only need to determine the winner on a two lane track, a logic circuit would do it. You could substitute a pair of LED's for the relays and line voltage bulbs I'm sure.

 

[Kinser Racing]

hi, i am wondering what a setup like this costs. we are a small troop and this is our first derby. we have a two lane track and dont really see the need at this time of a costly and complicated timing system. just a way to determine the winner for close finishes is all we need.

You can always do a rerun if you cant determine the winner. Most of us want a precise system. Ours measure down to the 10,000th of a second. /images/boards/smilies/smile.gif

Uh Kinser, the system described here measures down past 1/10,000 sec also.

Exactly! /images/boards/smilies/thumb.gif

He wants to keep it on the cheap, which I understand. This one and other timers we want to run really aren't necessary in a beginning pack. /images/boards/smilies/smile.gif

 

[mifd118]

thank you very much for all your info. im hoping the weather is good enough tomorrow for planes to fly so i can get to the mainland with all your info. it will be an all day journey im sure but hopefully i can pick up everything in one trip.

 

[Guest]

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[rmaltz]

Hi.
I am going to make one of these timers but have a question based on the schematics from the link in the first post. The schematics show an IR emitter for the finish lane timer, however a high brightness white LED (RS# 276-0017) is listed as the component used, which to me is not IR. Would someone enlighten me as to what component is supposed to be used? Or am I missing the boat.

Thanks very much,
Ron

 

[Vitamin K]

Hi.
I am going to make one of these timers but have a question based on the schematics from the link in the first post. The schematics show an IR emitter for the finish lane timer, however a high brightness white LED (RS# 276-0017) is listed as the component used, which to me is not IR. Would someone enlighten me as to what component is supposed to be used? Or am I missing the boat.

Thanks very much,
Ron

The Radio Shack part numbers are listed on the schematic, and you should go by these. My understanding is that the high brightness white emitter will put out enough in the IR spectrum to trigger the photodiodes.

If you're concerned, it would probably be pretty easy to rig up a test unit to make certain that the photodiode was triggered by the LED.

 

[rmaltz]

Thanks for the quick reply and answer. I didn't know if the listed LED put out any IR which prompted my question. I'm learning and appreciate your input.

Thanks again.
Ron

 

[Vitamin K]

Thanks for the quick reply and answer. I didn't know if the listed LED put out any IR which prompted my question. I'm learning and appreciate your input.

Thanks again.
Ron

Best of luck! Also, the dude who wrote up the schema and sketch code is pretty responsive to questions, if you get stuck.

I've got the parts onhand, but I haven't actually gotten my timer assembled. One of these days... /images/boards/smilies/wink.gif

 

[bracketracer]

Hi! VK answered correctly. They are visible light leds but they emit IR as well.

 

[rmaltz]

You guys are great as well as David! I can't wait to get the project rolling.

 

[bracketracer]

It's a great timer! Both of mine have been working flawlessly since I built them.

 

[bracketracer]

I'm going to stick this here since it goes along with the timer build. I'm widening my track from two lanes to four so I needed to build a new timer frame for the finish line. I used some 1" extruded aluminum square bars and some 1 1/4" x 1/8" wall aluminum square tube to make the frame. The extruded bar comes with a hole in the middle that is already sized for a 1/4-20 tap so assembly is easy. The 1" bar fits very snug inside the square tube and it makes for a rigid assembly. I was able to cut out the square tube to recess the sensors up into the track with adding any additional spacers like I did before. No welding needed on this frame. I'm not quite done yet, but here's a few pics of the construction:

I also wanted to add a wireless remote release for the starting gate. Since the optional PDT3 solenoid uses a 24v DC power supply, I went looking for something compatible. Turns out, many garage door opener and security gate controls operate on 24v! I found this single channel receiver on Amazon along with a pair of keychain style one button remotes. Wiring was super easy, I just tapped into the 24v power and ground and then used the normally open contacts of the receiver wired in parallel to the push button on my start box. I found a couple cheaper receivers online, but this one looked much easier to hook up. Four wires and I was done! I used Velcro to attach the receiver under the track. Range is no issue, the transmitter is good for around 500 ft. so you can drop the gate from the snack bar! LOL. I'll swap the keychain for a lanyard so I can keep track of the transmitter. The receiver is programmable for either a 4 second or a 1 second momentary on time, I set it to 1 second. Documentation says it would work with any AC or DC power supply from 11-24v so I bet it would work with about any start solenoid system. I included pics of the part numbers I used. Receiver was $31, remotes were about $17 each.

 

[GravityX]

Nice follow-up and upgrade to the already great track timer system you have. Well documented Stephen!