Remote Timing for Middle School Track using Arduino and Hardware

Projects General Guidance
1

Good afternoon Project Forum, and Happy New Year.

Backstory -
I am a Track Coach for a Middle School Team in Michigan and we work with a "Volunteer Army" of parents when they are available to contribute their time. Being volunteers, they have varying skill/interest levels of interest or integrity when they use the "pushbutton triggers" on the Ultrak L10 timing system. I would like to utilize an Arduino and sensors to control the start of the event (starter pistol Bang!). This would free up (1) Volunteer, and everyone can focus on the finish line.

I was originally going down a different path when someone on an engineering forum suggested using an Arduino. I have done some research and had the following ideas for hardware. I am very new to using/setting up anything with Arduino, I grew up with Electromechanical Relaying, so any insight/advice is greatly appreciated

Concept -
Attached is a Block Diagram of sorts to help explain what I am trying to accomplish and with what equipment.

Code -
None attached. I am totally new to writing any code, from what I have seen online a lot can be copy/paste. This would be my next step after knowing the hardware is correct.

Questions:

Remote system (stays with the Starter)

  • Is the KY-037 the right sensor to use to capture the starter pistol Bang? I understand that it has a pot to dial down the sensitivity accordingly.
  • Is the Seeeduino SAMD21 a good choice for this application? There are so many options, it is rather daunting. Is this unit fast enough to reduce the latency time to a minimum? The timing system measures down to hundredths of a second, I am unsure how much this would add. Repeatability is the main factor...if it reliably adds 6 hundredths of a second, I can factor that out.

Local system (stays with the Ultrak L10)

  • The Ultrak L10 uses a Plunger type pushbutton to close a Dry Contact to start the timer. Can the Arduino UNO DO pins be configured as a Dry Contact?
  • If not, what else would I have to use to close a contact on the timer?

Appreciation
Unlimited to those who are able to help. I am working on zero budget and volunteering my time with this as well as Coaching. I know there are FAT systems and their cost is in the $$$$ range, so it is out of the reach. We have the Ultrak L10 timer paid for so that is what I have to work with.

Track season is a few months away, and this would give me some time to acquire the components, assemble and de-bug on weekend.

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2

Take a look at this advice: How to get the best out of this forum - Projects / General Guidance - Arduino Forum

To many words and too little of schematics and code.

3

That would be nice. Do you have a link to documentation showing how use an external connection to the Ultrak L10 to start a race?

4

Good afternoon Railroader and Happy New Year.

Thanks for the link for the forum. I had started there before I posted as it seemed like the logical choice. It is always difficult to ask general questions to a forum of experienced people, as they are usually light years ahead of beginners. I was trying to avoid something similar to going to your mechanic with the statement "there is a rattle in my car".

Being very inexperienced with Arduino, I had included all of the information that I had access to, essentially just a concept at this point. Essentially a problem, the hardware and a project. I hoped my post would open a dialog with the community for just a few items at first.

  1. Does this concept have the potential for working? I searched other Projects and have found nothing similar. The components look like they should meet the build requirements.
  2. Has anyone used the components in a similar application? Maybe they have and have found something that is better or more specific to the application.

Thanks again for any information you can help out a beginner with.

5

Good afternoon Paul and Happy New Year!

I am unable to find the schematic of the Ultrak L10 Timer or the Link Gate that the Pushbuttons connect to. It must be proprietary information as a service or factory manual. I have attached some photos to show what I do have access to though.

The cable is a 4C and only 2 are used to close a circuit on the pushbutton (I took one apart). Red and Black are used to complete the circuit for the factory set up.

I did poke around with a meter and discovered the following:

Red = +2.6V with respect to Green and Black
Yellow = +2.6V with respect to Green and Black
Red and Yellow show continuity
Green and Black show continuity

Knowing this additional information, could a DO pin be assigned to provide that +2.6V and thus trigger the timer to start?

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6

Not unless the grounds are also connected! The digital pins only put out almost zero volts or almost the same voltage as the Arduino is using.

7

Such questions usually turns into "for ever" posting, exchanging ideas, but no real solutions. Maybe there are helpers that what appreciate "social chats". I prefer other long time social commitments.

That's fully okey. However You need to present what the large project is. You dig down in various low level questions.

Sorry but what that is is not clear at all.

It's a common member mistake to search for solutions ready to copy. They very seldom, or never exist.

Good luck but I leave this question.

8

Understood... thank you for your time and feedback.

9

Understood, I think..

So I would have to have the Arduino operate a external relay to "gate" the +2.6V from one wire to the other.

There is no way to directly connect the Arduino to the +2.6v and use it as a relay

10

Yes, you could do that, but who would be in charge of moving the system and getting it set up and working each time is was needed?

11

Good point.

We have an 8 lane track, so there are at least 8 volunteers for timing and 2 scribes for documentation.

The remote system (transmitter) would stay with the starter and his pistol (and KY-037), either at the common start/finish, 100M or 200M start lines. No worries on the distance because of the range of the nRF24L01+PA+LNA

The receiver (Timer) end would stay stationary at the finish line on a table. The Lane Timers are within a few feet of this, watching and ready to push their buttons when the student athletes cross.

With the Arduino components being static, I would expect them to have a reasonable consistency in their timing; KY-037 adjusted to starting pistol signal, transmission wirelessly from/to the NRF24, Arduino "sees" signal and had DO go "high" to operate relay to start timer.

We currently rely on a human to pay attention to the starting pistol and have found them to be inconsistent, sometimes missing the start completely.

12

My late company built, shipped and serviced similar timing systems for schools. Every year, late winter, we would get a raft of devices that needed repair because someone neglected to remove the batteries before storing away for the winter.

13

It all looks plausible and def possible.

If the only roll of the starter's unit is to send the gunshot signal along to a base station, you could use a radio set that might be easier to get going than the venerable NRF24L01. A fair amount of traffic here is ppl trying to get those working… which eventually they do, but they might have gotten further faster with another choice.

And the little board you've picked is nice, but I would go with one of the regular Arduino boards like the UNO or similar, as working with them is just easier. You might aim for a version zero that does not pretend to sexiness. Version 1 with lessons learned can be compact and whizzy or whatever.

Power the starter's unit with a 2s lipo or LiIon battery and a buck regulator for 5 volts. Those batteries come in a wide variety of sizes and capacities and can easily be designed to last for hours of use.

Treat all batteries with respect, read enough about the chemistry you choose to be expert enough on their care, handling and use including charging.

You can count on needing to experiment. The sound detector should be able to recognize the starter pistol sound, but verify. The putative range of the radio set needs to be confirmed in the real circumstances you intend for deployment.

Don't build the entire system and then try to get it working. You could start with a pushbutton on one Arduino that passes for the signal you want to eventually receive form the remote part and get the base station printing to the serial monitor having purchased nothing but one UNO or similar board.

Get each hardware feature working using example code you didn't write or mess with too much; keep these early sketches handy for trouble shooting when trouble starts making visits.

Sounds like a nice project.

a7

14

Yeah, usually when XC season ends things get put away in a rush. I have the advantage of being the Head Coach so I am keeping the Timer with me. I fitted a Pelican Case for the Timer, Plungers, batteries, etc so it will be obvious if anything is missing.

15

Good morning alto and Happy New Year!

Thanks for taking a look at my project and giving some feedback.

Can you elaborate on the radio set that you had mentioned instead of the NRF24L01? I am a believer that "simple is best" and appreciate this type of suggestion.

Since size is a factor at the stater end, is there an Arduino equivalent to the Seeeduino that I can use once I verify "proof of concept" with the UNO?

16

The runner's ears are the right sensor to pick up the starter pistol "bang". Using your max distance of 500' there is the speed of sound to consider, in that case, 1/2 a second between where the starter is standing and the starting line.

This looks to be an X-Y problem to me.
https://xyproblem.info/

I think the system you have in mind, at minimum, is leaving you as the Coach open to all sorts of nasty parental criticism, especially if your athletes have aspirations of College Track Scholarships.

Not trying to rain on your parade, as a 10-year uber-amateur Arduino hobbyist myself, building this project as you have outlined will feel like you're pushing a wide swathe of snow on the end of your shovel the whole length of a long driveway; that is, it will be enough work at the start and toward the end, will feel like a frustrating, insurmountable chore. Powering each stage, calibrating, and especially troubleshooting on race day when you have a whole day's worth of races to get through will make this feel like more trouble than it was worth.

I like that you're trying to get the best out of your athletes and deliver the best possible track sport experience to all involved, I'm not trying to discourage your goal.

As others have alluded to, can you maybe step back from your project as designed for a moment, and address specifically the problem you're trying to solve? No parts or suggestions as to how the code might work, just the problem that you're hoping to solve/streamline to avoid other potential X-Y paths.

I think (hope) the other helpers here would be happy to look at your project from that perspective to help get you on track (pun intended :slight_smile: )

1 Like
17

Endlessly, with variabke authority and competence. :expressionless:

I thought of a very low rent beginning project that will test your mettle and possibly provide feedback and direct your next steps. It might also inspire confidence and be a sales tool for anyone on the fence in your group.

Buy a remote control key fob and receiver. I just googled

433 key fob and receiver

This simple device will provide action at a distance. It should be easy (!) to implement the system using nothing more, for now.

But it will drag you over some things that you will need to be dragged over, so not a waste of much time or money.

The range may be inadequate and the performance poor even in range. This is also the kind of thing you'll have to deal with.

Before you buy anything, post links here. When I am at the big rig later I'll look myself. They are all similar, so.

Now for the "real" project, we just need to close a relay at a distance without too much dealy and reliably.

I suggest the HC-12 half duplex modem. A pair of these will have the range, and could "talk" far beyond sending a 'X' to make the start relay close.

Another option is the SRX822+ FSK radio set. This is somewhat primitive, but software to the rescue.

Both those are fairly easy to get going, there are good libraries you can exploit.

With bidirectional comms, you could have a ping-pong idle state conversation going, so the remote unit could indicate its readiness to reliably send the start signal.

And the remote knows when the race started, so even if it failed a few times, the receiving unit could know that, and provide a "yeah but add" time that would obvsly just need to be added to all times. I dunno how that woukd work in a real race.

In fact I am in agreement with @hallowed31. These things sound good and can look good right up to the moment of truth… so while I do not think you shoukd give up, I will say this might end up being a different kind of fun than it seems.

As for your other question, I build toys and use the Pro Mini, it's a smallish board but is a low end Arduino and when I am working on the logic I use UNOs and never care which is which. The UNOs have the female headers and I use Dupont wires and add devices that are similarly equipped; when it's time to rock and roll there are no remaining questions (well, that's the goal anyway) and the focus is on hardwiring the miniaturized version.

Did I say here I use Lipo batteries of two cells? The chemistry is a bit dangerous, but they are a great source of power and can be tamed. I keep using the word "easy" - all this stuff will be hard until it is, for you too, easy.

a7

18

Thanks for the insight on this.

My first problem is a human one. The person who operates the starter pushbutton is inconsistent - Solution Arduino! Automation and Repeatability.

KY-037 would be 3' or less from the starter gun - sound traveling to the sensor should be a non-factor

nRF24 wireless communication delay across 600' with no obstructions- unknown - have to test and verify. I would assume very fast though

Single Channel Relay triggered by Arduino - <10ms

1 Like
19

Good evening Alto and thanks for the additional information on this. I will dig into the items more this weekend, work has been a bugger lately and keeping me busy.

20

Here is a commercial system example....I can't imagine that there is gold in those black boxes...

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....and the price!

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Includes Wireless Trigger System (as listed below), Power Supply, Belt Clip, 2 x Antenna, 6' USB Trigger Cable, Gun Sensor, Bungie Cord and Hard Sided Carry Case.

Trigger System

  • FCC Extended Range Frequency up to (2miles) line of site
  • READY light for Seamless Communication Between Timer & Starter
  • Connectivity Light Allows for Single Operator Set Up
  • Waterproof Sensor Port
  • Rugged Housing
  • Can be Used with or without External Gun Sensor
  • Flexible Low Profile Transmitter Whip Antenna
  • Low Battery Light
  • Can be Used with E-Guns such as the Halo.
  • Belt Clip

Gun Sensor

  • This Optional Gun Sensor Connects to Sensor Port

  • Specialized Sensor is Encapsulated within Protective Housing

  • Wind, Rain and Touch Proof. Can't be Pre triggered

  • Magnetized! -Connect Directly to Your Gun of Choice

  • Removed Sensor from Starters Hand!