How To: A Digital Clock For HLG Contests... - RC Groups
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Sep 22, 2009, 08:23 PM
Adam RED Weston
RED_HLG's Avatar

How To: A Digital Clock For HLG Contests...

So, my trip to the German Open in 2008 started me on a quest... a quest to run a contest with, well, German precision! A big part of this was an integrated computer system with a PC running a digital clock and an audible system like what we're used to.

Over the next couple of installments, I'd like to take you through:

- The clock I chose, and the others that are out there on the web
- The programming of the clock and audible portion in Visual Basic
- The details of the system in its current form
- Future upgrades
- And finally, gather inputs from the group on what should/could be improved

I hope you enjoy, and are maybe even interested in a similar system for your flying field.
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Sep 22, 2009, 08:53 PM
Adam RED Weston
RED_HLG's Avatar

Digital Clocks - What I Was Looking For

There were several important parameters that would play into my decision on which system would work best for my club.
  • Visible from the 'typical' F3K landing zone... in the day-light
  • Runs on 12V DC so I don't need a generator
  • Could be positioned away from the scoring tent... i.e. in the direction people are looking when they fly, maybe even 2 clocks...
  • Computer controlled - needed to work in conjunction with the audible countdown that we are all used to at F3K contests, also allows for flexibility as rules change, or the club wants to use for F3J or something else
  • Cost - Our club had budgeted around $1,000 for this system
In the next post, I'll walk through some of the options that are out there...
Sep 22, 2009, 11:28 PM
Transplant Chey WY from Reno
Thermaln2's Avatar
This is going to be a great post Adam! The clock system at the Open was sooooo nice.

Sep 22, 2009, 11:30 PM
Registered User
ASK's Avatar

You rock, Adam.
Sep 23, 2009, 01:11 AM
Adam RED Weston
RED_HLG's Avatar

The Clocks - What's Out There

A list of websites offering displays follows, along with a few comments as I weighed my needs above against each offering. I've split them into LED (little red lights), incandescent (little white light bulbs, what the Germans used), LCD (Liquid Crystal Display) and electromechanical (think score board at the baseball game, with little yellow tabs that flip from black to yellow to show the time)

Electromechanical - could be a good choice if you find one with a computer control. very visible in day light. Could have maintenance issues down the road. More expensive.
EDIT: Computer control IS available!
- No computer control. Very visible. Price is good. Upon discussion with the vendor, they could program 10, 8 and 5 minute rounds. Has a horn!
- No computer control (i think), very visible, price a little high, not 12 VDC?

Incandescent - Like what the Germans used. Bulbs can burn out so you may need to buy a supply of them. These seem to be the most expensive choices, but are great in the sunlight. Could be the best answer if price is no issue.
- Very visible. Pricey

LED Clocks - Best value, usually computer control available, not the best visibility in bright sun light. Lots of options out there.
Pricey for what they have. selection, price isn't bad, computer control, has Farm right in the name. small, good price, computer control, may not be visible in sunlight
Nice and big, I didn't get a quote... probably expensive, you can get your club logo on it!
Wasn't obvious these were computer controllable
Also wasn't obvious these were computer controllable
Not computer controllable(?), good price for 13" display, 110 VAC
Not the best website, but ATS ended up being the best bang for the buck, met all my criteria and was ultimately what I went with. More about ATS later.

LCD Clocks - cheapest, not really satisfactory for outdoors, I wasn't really serious about LCD
Last edited by RED_HLG; Sep 23, 2009 at 11:48 AM. Reason: correct 1st link
Sep 23, 2009, 07:08 AM
Soaring Circuits
rcbrust's Avatar

Your first link, Electro-Numerics, does have an RS-232 ASCII version. Link here.

It would be nice, and very flexible, to have the display computer controlled. May be others out there too.

Sep 23, 2009, 11:52 AM
Adam RED Weston
RED_HLG's Avatar

Electromechanical Clock

Agreed, Electro-Numeric's 6" at $1300 or 9" at $2000 electromechanical might be a great solution. As you'll find out later, the LED ones I chose are not perfect in bright sunlight... but get the job done.
Sep 23, 2009, 06:46 PM
Your user title is suggestive,
Xptical's Avatar
Who has time to watch a clock?

I want an MP3 that counts off in 15 sec intervals. Then, I can wear my iPod and know how much time has passed...
Sep 23, 2009, 07:27 PM
Adam RED Weston
RED_HLG's Avatar
Originally Posted by Xptical
Who has time to watch a clock?

I want an MP3 that counts off in 15 sec intervals. Then, I can wear my iPod and know how much time has passed...
The software I wrote (more on that later) could do that with some rewriting... Might be good for practicing.

But I've found with the minute counts I miss them all the time and that it was easier to glance over at the clock when I WANTED to know, not necessarily when the .mp3 wanted to tell me.

Sep 23, 2009, 11:00 PM
Registered User
Plus you can always ask your timer how much time is in the round and they can glance over at the clock.
Sep 24, 2009, 03:49 PM
Your user title is suggestive,
Xptical's Avatar
Does time start when you throw, or when your DLG peaks? Since I'm my own timer, I usually start the clock on my TX when the DLG is just about to peak.


I wasn't thinking about the clock in competition. I was thinking of an MP3 for personal practice sessions.
Sep 24, 2009, 04:31 PM
Chuck 'Em and Chase 'Em
Fly2High's Avatar

What did you purchase in the end and how much was it?

How hard is it to program?

Can you give us additional details?


Sep 24, 2009, 04:32 PM
rational exuberance
Dunqun's Avatar
Xptical, It starts when it leaves your hand and ends when you catch it, or it touches any land-based object like people, trees, buildings. A lot of us use this talking timer attached by velcro to the back of the transmitter:

Talking Timer

Sep 24, 2009, 04:40 PM
Panda Panda Panda Panda Panda
rdwoebke's Avatar
Originally Posted by Xptical
Who has time to watch a clock?

This clock is for contests and the typical use of the clock is to show the pilots/their helpers how much of the 10 minute flying window has elapsed. Typically in hand launch contests you get a 10 minute window to make say three 3 minute flights and knowing the time left in your window affects your strategy for when to make your throws. You might not actually be flying when you glance at the clock. Or as James mentions you might ask your timer/helper to glance at the clock for you.

Adam, nice thread. Good work sharing all this data.

Sep 24, 2009, 08:40 PM
Adam RED Weston
RED_HLG's Avatar

What We Ended Up With

I ended up settling on 3 or 4 clock manufactures, and got quotes from all of them. There was one electromechanical that I worked with for a while and they were able to program a 'typical' round for me 3min prep, 10 min window, and 30 sec landing, but this would all be hard wired... and we wouldn't be able to do something new. In retrospect, I think I would have followed up more with Electro-Numerics and their computer controlled system...

The LED quotes all came back similar, but ATS was the cheapest. In fact, they were cheap enough that we were able to get a 4" clock and an 8" clock for about $1200.00.


They both take the same computer inputs through RS232 also known as your serial plug. I had them wired to run on 12 V DC, so I can plug into a winch battery, or I can also run them using a wall wart (also provided by ATS).

They arrived a couple of weeks after I ordered them... each order being custom. The wires were pretty nice coming off the back, one for the computer hook up and the other a plug that looks like the charging jack for my Futaba TX. They also came with a CD and an owners manual.

Owner's Manual

RS232 Manual

One thing I wasn't in love with with the clock is the mounting bracket. As you can see in the manual, they are expecting the clocks to be mounted to a wall or something, so there's a bracket that goes on the back. I want to mount it on a tripod or something similar, so I'll have to rig that up over the winter. For now, I'm setting them on step ladders, and that's cool.

Unfortunately, all the programming that was provided was for MS Quick Basic which modern PC's don't like too much. I thought about running the clock stuff with an OLD laptop I have, but quickly remembered, they didn't have Sound Cards back in the 90's (how crazy is THAT!) and so it wouldn't do all the other stuff I wanted. So, that ties into the next installment Programming...

Note, the clock displays look odd in these pictures out at the field because the LEDs actually flicker at a very fast rate... nothing you can see with your eyes, but my camera shooting at 1/1000 was able to pick it up.

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