I am a drag racer, and big time DIYer. I race a dragster, and would like to build an LED dial in board that I can control from inside my car. Basically I need a board mounted outside the car that will display a time (ie:8.07, 8.10, etc). I need to be able to change that from inside the car. What I'd like to ask before I start researching it out, is a rough guess of what I can expect to spend in materials. If it's a few hundred dollars, its not really worth it as I can buy one for around $350. I'd prefer to make my own setup cuz thats how i am. Thoughts? I appreciate any help

 

You're talking to nerds. Most of us don't even know what a dial in board is. How about giving us some clues?

Edit: Ps, welcome to AAC.

 

Welcome to AAC big ragu.

A few questions we need answered before we could even guess at a cost:

1) How big do the digits need to be, i.e., height?

2) I assume this will be outdoors - during the day, night, or both?

3) How many digits do you need total? In other words, what is the maximum time you'd expect to need? I know nothing about drag racing, but you mentioned 8.07 and 8.10. Is that M:SS or S:mSmS or something else?

4) How would this operate? Please let us know exactly how many buttons you'd need and what they do. Example: one button for start and stop (or one button for each), a reset button, etc.

5) What is the maximum distance you expect to need to control the display from?

6) Could you post a link or two to the ready-made version you said is available for $350? This would give us a better idea of what you have in mind.

The control electronics shouldn't cost much. The majority of the cost will be in the display - its size, brightness, making it reasonably weatherproof, how nice you want it to look, etc. Money can still be saved here by building the LED segments yourself instead of buying something pre-made.

Also, what is your background in electronics? You can save some money on the electronics using a microcontroller instead of pure digital logic if you've got some programming experience, but it's not a requirement in the least.

 

Sorry. http://www.biondoracing.com/DialBoard.shtml

If you take a peak at that link that's what I'm looking for. Its nothing more than a board that displays a preset time. I don't need it to read 4 places, just three (8.00 for example).

 

I believe that's 8 seconds, then tenths, then hundredths of a second.

So...it's just a display, doesn't transmit to a receiver, right?

No start or stop, just increment /decrement until the right number shows on the display?

I think 4 digits is the right thing to do in case your car breaks and you have to drive a Ford.

 

Im sorry, I have given no background or intro or anything. I'm a maintenance manager/mechanic by trade, I work on industrial equipment. Most are run by plc, I have a fair bit of experience reading I/o's, some programming. Relays, starters, etc. Outside of work I'm a fabricator, mechanic, machinist, blah blah. I just like to do my own stuff. Generally when I want to do something I research it to death and then do it. I just like the satisfaction of doing my own thing instead of buying or paying someone. I appreciate any help, this is something I'd really like to build, and then from there there's a bunch of other electronic projects I'd like to accomplish.

 

Welcome to AAC big ragu.

A few questions we need answered before we could even guess at a cost:

1) How big do the digits need to be, i.e., height?

2) I assume this will be outdoors - during the day, night, or both?

3) How many digits do you need total? In other words, what is the maximum time you'd expect to need? I know nothing about drag racing, but you mentioned 8.07 and 8.10. Is that M:SS or S:mSmS or something else?

4) How would this operate? Please let us know exactly how many buttons you'd need and what they do. Example: one button for start and stop (or one button for each), a reset button, etc.

5) What is the maximum distance you expect to need to control the display from?

6) Could you post a link or two to the ready-made version you said is available for $350? This would give us a better idea of what you have in mind.

The control electronics shouldn't cost much. The majority of the cost will be in the display - its size, brightness, making it reasonably weatherproof, how nice you want it to look, etc. Money can still be saved here by building the LED segments yourself instead of buying something pre-made.

Also, what is your background in electronics? You can save some money on the electronics using a microcontroller instead of pure digital logic if you've got some programming experience, but it's not a requirement in the least.

1. Id have to take an exact measurement, but roughly 3.5" tall
2. It will be outside, both day and night. It lives inside unless I'm running it, may see some rain occasionally.
3. 3 digits, up to 9.99. It'll never actually read that high, but I do have other cars that I may want to make one for. It reads M.SS
4. It isn't a timer, it just needs to display a figure that I tell it to. I need to be able to tell it to read a number, it doesn't actually count it.
5. The distance would only be about 15' max, but probably far shorter.

Again, I definitely appreciate the help!

 

I believe that's 8 seconds, then tenths, then hundredths of a second.

So...it's just a display, doesn't transmit to a receiver, right?

No start or stop, just increment /decrement until the right number shows on the display?

I think 4 digits is the right thing to do in case your car breaks and you have to drive a Ford.

Lol 4 digits actually would be good since I do have some slower cars I'd probably build one for. Its literally just a display, no counter. It's seconds, tenths, then hundredths. I really just need it to read a number I tell it to, and I need to be able to change it from the drivers seat.

 

Something like this?

 

Something like this?

Yes exactly. Nothing too ridiculous, something simple like that

 

Cool beans. 3.5" isn't a standard size unless you'd like to make them yourself (not hard though). You can get these pre-made in 3" or 4", roughly $4 to $5 USD, respectively, each.

I've done something similar, so I can put together a schematic using CD40110's which will accept a button push input and increment the digits all-in-one. Will probably need to add transistor or MOSFET between the IC and segments though, but we'll see.

The complexity, if you will, will be the mechanical enclosure for the display. Based on your background though, I doubt this presents a challenge. You could simply buy a big enough plastic enclosure, ideally with some UV protection, pop the digits in, pop in a jack of some sort, and add a filter which will be a piece of colored acrylic that goes over the display so you can see it clearly. Do you have a preference on color, e.g., red, green, or blue? Blue is ideal for outdoor displays in daylight conditions, red is cheaper and good for nighttime. The human eye responds best to green. In this case, I don't think these factors are of much concern, so really any will work.

Are you planning to use power from the car or batteries? While LEDs aren't power hogs, displays can eat through a battery pack in several hours - not a problem if you plan on powering the unit for an hour or two at a time and don't mind replacing batteries, but if you have 12VDC or more available from the car, you can eliminate this concern. Do drag cars have an auxiliary power jack - what used to serve in the U.S. as a cigarette lighter jack?

Your link shows a (LCD) display on the control module too. Is this something you need as well or just the big display?

Since you don't need a clock and the digits aren't too large, I think you could build this yourself for $100 to $200 in parts. I'll have a better number once I've got a schematic made.

 

The ball is in your court now. You have to make choices about color and size. Probably the latest in superbright LEDs. Size will dictate how many LEDs and how many LEDs will dictate the power transistors.

 

4" would be fine I'm sure. Or perhaps even bigger, I'd have to have the car in front of me to know for sure. I would power it from the car, which is 12v. The control would be hard wired right to the car. Color isn't overly important, most that I've seen is red or blue. Im fine with any color really, I guess blue would be my preference. The lcd on the control is somewhat important, as I need to know exactly what the board says from the driver seat. I need to adjust it without getting out and I need to know what it says. The enclosure itsef should be relatively easy I would think. I'd love to build the first one, test it for a while, then build a few more for the rest of our cars.

 

So you need 2 displays.

 

So you need 2 displays.

I apologize, I wasn't thinking earlier. Two displays, a small one on the control box and then the large one. It is very important that I know what the board outside the car reads. Also, the first digit would never need to read anything other than 1 (for example: 10.00).

As I am pretty new to this, can you guys point me to a website where I can find the parts necessary to build this? As I get rolling here I am going to have a million questions. I totally appreciate all the help so far!

 

A few things need to be sorted out before you order any parts, namely a schematic - otherwise you'll be making multiple orders and paying multiple shipping costs before you can begin. Are you located in the U.S. or elsewhere? This helps determine the best places to order from. Also, the schematic will give you a final list of parts to order - most will be available from multiple suppliers, but a few may only be available from one or two suppliers.

I'm working on a schematic, having two displays adds a little complication, but not much. Is an LED (vs an LCD as shown in the link you posted) display okay for the inside of the car? It would be much smaller than your outdoor one of course. It's easy to use a small LED display. I'm sure LCDs are easy, but I'd have to experiment with one before I could comfortably design it into this.

How many of these, once the first one is hashed out, do you potentially plan to make? For more than a few, you'd save a lot of time designing and making (or having made) a PCB.

 

A few things need to be sorted out before you order any parts, namely a schematic - otherwise you'll be making multiple orders and paying multiple shipping costs before you can begin. Are you located in the U.S. or elsewhere? This helps determine the best places to order from. Also, the schematic will give you a final list of parts to order - most will be available from multiple suppliers, but a few may only be available from one or two suppliers.

I'm working on a schematic, having two displays adds a little complication, but not much. Is an LED (vs an LCD as shown in the link you posted) display okay for the inside of the car? It would be much smaller than your outdoor one of course. It's easy to use a small LED display. I'm sure LCDs are easy, but I'd have to experiment with one before I could comfortably design it into this.

How many of these, once the first one is hashed out, do you potentially plan to make? For more than a few, you'd save a lot of time designing and making (or having made) a PCB.

Thank you for the reply. I am located in the US, NY to be exact. LED is perfectly fine for the inside display, it really just needs to tell me what is displayed on the outside board. I think once the original is made and completely tested, I'd be looking at at least 2 more. Possibly up to 7 total as we do have several cars. Depends on the cost to produce, and ease of use. At no point would I be looking to sell them, it's just we have a bunch of cars and outfitting them all makes sense.

Really I'd like to use this to jump start a bunch of other electronic projects that I have in mind.

 

Alrighty, that helps give us an idea. On further thought, I realize having two displays could be a bit of a wiring nightmare since they'll be in two locations. So one question comes to mind, where does the large display sit? Is it possible to put the small display on the side of or the back of the larger display outside the car and just mount the switches inside the car?

 

The large display mounts towards the back of the car that it is not visible from the drivers seat. It is a must that the small display be inside with the controller. I have to have the ability to know what is displayed outside the car.
Just some quick background on why I need this. Right now the car has a board that displays numbers mounted behind the motor. Its just a ribbon with numbers on it that you change by turning a wheel. Its not lit, not electronic, etc. I was in the car fri night about to pull onto the track and couldn't remember if I had changed the number from the last round. Because I couldn't see it I didn't know if I had my delay box adjusted properly (basically a timer that tells the car when to launch). I do not want this problem again.

 

Okay, thank you for the explanation and background, that is always helpful. I've got a basic circuit started, but at the moment, we're looking at 25 wires or so. I think I can get that down lower, I just need to investigate some other options.