Building a Race Clock

Allow for TCP or UDP connection to the clock. Preferably UPD. I'm not personally a fan of wireless (802.11). I'd rather have a wired network.

Why not buy a used display that already works with Lynx if you are on a budget?

I'm not really on a budget, just thought it would be a fun project.

Who has used displays available? I don't see them all that often.

I've built two. They were a fun project. Cost was about $300 for each. One was a wired ethernet, the other used WiFi. We use the WiFi one on the 200m mark, and the wired one at the finish line. I'd say it took about 100 hours or so designing and building.

Basically I used a raspberry pi to perform the clock display logic and a virtual com port to send data from FinishLynx to the pi.

The clocks are made of 250 high intensity LEDs, organized as segmented strips in a ##:##.# fashion, and do a great job in bright sunlight.

I can post more info if anyone wants it.

I have built an ethernet clock using an arduino, worked great with lynx, only issue was that the LEDs weren't bright enough. Definitely a fun project

Love to see pictures! How bright are they?

The LEDs I used were rated at 20000mcd

http://www.amazon.com/Bluecell...light/dp/B006G6TKQW/

Each digit's segment is composed of 7 of these babies. They were so intense, that I actually had to diffuse them with two layers of fluorescent light diffusers.

Here's some pics:

At the track:
https://drive.google.com/file/...TZj/view?usp=sharing

Notice the battery. This 35ahr will run the clock for about 14 hours:
https://drive.google.com/file/...VEE/view?usp=sharing

Here's the clock at a distance
https://drive.google.com/file/...dnM/view?usp=sharing


And the electronic guts:
https://drive.google.com/file/...cDQ/view?usp=sharing

The Raspberry PI with WiFi:
https://drive.google.com/file/...QnM/view?usp=sharing

Wow... Cool stuff guys. Would love to see some of the Arduino clock pictures.
Thanks!

quote:

The clocks are made of 250 high intensity LEDs, organized as segmented strips in a ##:##.# fashion, and do a great job in bright sunlight.

Why only for displaying tenth?

Ciao

dirk

Well, When a race is happening, FinishLynx will only output a maximum resolution of a tenth of a second. For track we don't need any an hour digit, so for us, a clock that displays MM:SS.t is perfectly fine. This isn't a scoreboard - just a finish-line clock.

Ups - Our System will give us hundreth.
That's why I am wondering...

So do you start the clock manually? THEN we will have thenth only too...

Ciao

dirk

DudeMan this looks great. One question though: I can see you used wooden material for the housing. Are there any issues with water/humidity? Any side-effects of the black housing in terms of heat? Or are you using fans to blow out the heated air?
Cheers
ML

Yes, I used 1/8" wood for box since it is a material I can work with. As we are in SoCal, our youth track season (March-June) rarely gets wet, but that would be an area of improvement. Paint can only protect so much.

On the first clock I made, I used a PC power supply - which does generate enough to heat that I needed to vent, but a fan attached to the grill on side takes care of that. For the second clock that runs on battery, passive venting is all I needed.

Cheers!

Could you post a block schematic of the LYNX/RasPi arrangement and the logic which drives the LEDs? I can see you used discrete transistors (1 for each segment).
Thanks

Here's a sketch up of the LED array use for each segment on the clock, composed of 7 LED's and 7 100-ohm resistors going into a 2N2222a transistor that is driven by 74HC595 shift register.

https://drive.google.com/open?...x4MnFmZHM&authuser=0

And here is a sketch up of the PI to a BiDirectional Level Shifter to the 74HC595 shift register.

https://drive.google.com/open?...9zajZ0OW8&authuser=0

(Sorry for the rotated images).

I know this post is quite old but I've been thinking of a similar project
does your display need much code in order for it to interact with the FinishLynx system?

Hey,

Yes, the project does require quite a bit of programming and electrical engineering knowledge. I did complete the project, but it took a while. The design is not as robust as it could be but this is just my first version. Someday, I will make a better version.

If you have the FinishLynx Network COM port plug-in, then you only need to program a network UDP socket receiver and then output to bang'ing the GPIO pins to light up the LED segments. I did mine in C/C++, but I imagine it can be done in Python too.

Data sent by finish lynx is sent as you'd expect - dependent on what *.lss script you used - I just made my own.

Now if you don't have the Lynx COM port plugin, then you can either buy it for $500 (I think that is what it cost), or you can do what I did and use an open-sourced COM0COM driver that creates a pair of virtual com ports. The way COM0COM works is all data received on one COM port of the pair is output to the other COM port of the pair and vice-a-versa.

You configure FinishLynx scoreboard to use one of the COM port you created, and then on the other com port you have a program that reads that COM port and forwards all data out on an UDP port - which gets sent on on the network to your PI.

Thanks for your prompt and detailed reply
I have a Daktronics timing display and a Gill ultrasonic wind gauge
Both communicate with the FinishLynx PC using a USB-serial cable linked to a serial-bluetooth adapter.
The link works very well

Although it would be nice to have a'cheaper' timing display (clock), I am thinking now of a display which shows the output from the wind gauge automatically
These are available from Gill but are very expensive

The wind gauge has two DB9 (RS232) ports and the device outputs a series of bytes (about 18 bytes - only the middle 5 bytes carry the data) when it has acquired one set of data (race completed)
One port interacts with the FinishLynx PC and the other is (at the moment) unused
I hope to use the unused port to send data to the (planned) display

This would need only two digits with a permanently lit decimal point in between + a few LED for the '-' symbol where appropriate
This would be a lot easier to build

This display can be close to the wind gauge so can be linked with a physical cable

I know that I can add a RS232 module to the Raspberry - can that be used as an input, then transmitting that data to the LED segments?

Thanks for your help?

I've completed the Basic Stamp programming and built a simple schematic on a breadboard
I'm having problems with the transistor serving the LED
they simply flash when a signal arrives but naturally I want them to stay illuminated
any clues as to how to do this
note that the schematic is not intended to be a running clock

Sorry, I'm not familiar with the BASIC Stamp Micro-controller. However, you should be able to diagnose where your problem is quite easily. With your breadboard, jump the +V to to the base (B) of your transistor. Your LED controlled by the transistor should illuminate and stay illuminated. If this is so, your flashing problem is caused by the device that signals the transistor, (I'm guessing is your BASIC Stamp).

I've just realised that the flashing was due to the DO...LOOP code that I had inserted into the programme
that is now solved

If I only want to display an intermittent reading from the wind gauge, is the transistor necessary?

thanks for your help and interest

Most outputs from shift registers or GPIO pins have a maximum current capacity of about 20 mA - much more than that and you will fry the device - check your datasheet to find out what your will be. To handle a heavier load, we use a transistor like the 2n2222a which can switch a load of 800 mA.

thanks
I'll build my circuit and let you know how I get on