okay guys, i want to build some drag strip lights for myself. they are going to be for my electronics project at school. I need to know if some body has any schematics or knows how to do this. i was thinking two roes of lights on a 2x4.

 

Are you doing a laser that will activate a red light or just three yellows and a green? What about staging lights?

What kind of power are you looking at using? 12V? 24V? 120V AC?

One way is to use timer relays. That'll cost you about $50 a relay and you need at least 8. Another way is to use flip-flops and a timer. Don't know how much the timer will be, but I'll look around online. This should be cheaper overall. Third way is to use a microcontroller. This would be the simplest hardware-wise, but unless you know how to code in assembly, I wouldn't suggest it.


[Modified by GTLocke13, 7:36 PM 11/8/2002]

 

ok don't the lights go like this:
red
red
yellow
yellow
yellow
green

ya and i was thinkin about using floodlamps, 12v would be good so i can actually use it. also if i was to code it(we have stamp chips at school) i would just make it so it goes red, then wait 1 sec,yellow,wait 1 sec, yellow, wait 1 sec, yellow, wait 1 sec and then go green? is this the way. if not can u tell me where i can learn how drag lights work.
thanks

 

Ok, just figured out the cheapest way to do it.

Use a pulse width modulator to create a 2 Hz square wave. Use a bunch of D flip-flops and relays to turn the lights of and off. Then just some control circuitry for the staging lights and the red-light detection and a pushbutton to set the whole thing off. I figure you could build the electronics for less than $50.

If you wanted it to be really cool, you could put a timer in there to give you reaction times.

 

Ok, here's how the christmas tree looks:

http://www.budpark.com/deducation.asp?page=tree

And here's how it works:

http://www.nhra.com/basics/

The yellows go every half second.

I can't explain to you how to build something like this, even a very simplified version, over a forum. E-mail me at GTLocke@hotmail.com. I'll go look around the web and see if I can find some articles explaining how flip-flops and PWMs work. If anyone else is interested (doubtful), e-mail me and I'll cc you on the e-mails.


[Modified by GTLocke13, 7:54 PM 11/8/2002]

 

once you get it done.. please post a how-to. This would be great for my game room. How are you going to trigger the reaction time? pedal? button? how are you going to display reaction time?

 

For details on about drag racing and how the tree works try this site: http://www.staginglight.com/

To simulate a real tree, you could wire it so that the staging lights on both sides have to be lit and start the tree say 0.5 sec after the last staging light is lit. Then time each yellow to come on at 0.5sec intervals with the green comming on 0.5sec after the 3rd yellow.

Since you will be using it to practice, you will need to be able to set the pre-stage and the stage bulbs as well as dial in the car's reaction time (i.e. roll out) and you will need a trigger to test your own reaction time. Finally a display with your RT and a reset button would finish it off.

You could use a 555timer (use NPO caps to minimize timing drift), simple TTL logic with some flip-flops and drivers on a bread board, or you could interface with a PC to do the timing duties. It all depends on your budget, time and abilities.

Physically, on each side of the tree, you need the smaller pair of yellow pre-stage and and pair of yellow staging bulbs across the horizontal, three larger yellow bulbs down the tree followed by a green and a red bulb.

Sounds like a fun project, enjoy.

PS, as a bonus you might have it switchable to a Pro-Tree with all three down bulbs comming on at once followed in just 0.4sec by the green light.



[Modified by 65Z01, 8:05 PM 11/8/2002]

 

Well the electronics woul be easy.

But would anyone pay $200 for one?
( I'm figureing about $100 for parts... )

[edit]
Oops, I guess I didn't answer the orig question....

There are two ways, well three but the third is messy.
A PLC
A single chip computer
Descrete logic, relays and stuff.

The first two would be the cheapest and most versitle since they're soft.
The last one would be a pain most likely 3-4x more expensive.

The hard part of the last one is the logic involved, and the timing of the yellow lights. You'd either have to have 8 time delay relays or two sequencers Or I suppose you could use the 555 idea and shift a bit around. But you still have the logic problems of staging, redlighting etc.

Me I'd use a PLC


[Modified by 427V8, 11:20 PM 11/8/2002]

 

Actually, the discrete logic would be cheapest if you're just building one. A microcontroller will run you about $80 and for a PLC, you'll need the programmer, which is expensive. Plus, with both of those, you still need all the relays. They won't drive incandescent lights.

 

When I said 'descrete logic' I was thinking time delay relays and stuff. I guess I should have said something else.

If you did it with 7400's and cheap relays it would be cheap yes...
Then again I can get a PIC for like $5.00


[Modified by 427V8, 9:27 AM 11/9/2002]

 

battsup, I assume it is a HS electronics project, but what is the scope and budget?

There are commercially available "practice trees" available in the mid US $500 range and I am pretty sure these are microcotroller driven. These have most of the bells and whistles of a real tree.

First you need to set the scope (immediate and maybe future expansion) of the project and then break it down into small easily managable parts.

If the project is beginning to look a little complex, don't give up on it. It will not only teach you some electronics but project management as well, both very useful skills in the real world as well as racing.

 

You guys were talking about a pls is that the same as a stamp chip, casue we have those at school and we also have the programmers.

 

Unfortunately, a PLC would have trouble with this. PLCs are great at implementing a bunch of discrete logic, but they suck at implementing timing. To really do it right, you need a full-blown microcontroller. If you have a PIC programmer at school that would work, depending on what kind of PIC. Also depending on if you know how to code for it. Assembly is a bitch for this kind of stuff and you don't want to know what the C+ development package for PICs costs.

 

Battsup
Pls? never heard of it, do you mean PIC?
If you have a PIC programmer you should use that. PIC's rock!
( Basic stamps rock too )
It would be very easy to have the pic controll some cheap relays.
And yes the basic stamp is based on the PIC processor.

GTLocke
PLC's suck at timing? since when?
Event the cheap PLC's have a timer...the $99 Direct logic D05 has 128 timers.



[Modified by 427V8, 4:07 PM 11/12/2002]

 

Sorry, I was thinking PLDs, not PLCs.

The whole point is moot though. I've been talking to battsup over e-mail and I've got a schematic drawn up using 7400 series chips and a couple of op amps. I know PICs are only $5, but like I said before, I wouldn't want to write the code for it in assembly. :nonod:

Besides, its a school project. He'll learn something from building and debugging discrete logic. He won't learn anything from having someone give him a bunch of assembly code to burn to a PIC.


[Modified by GTLocke13, 10:14 AM 11/13/2002]

 

good luck with your project. I wish an A for you

 

GTLocke
Spoken like a true hardware engineer! LOL
BTW there are free dev tools for PIC, i.e. GNUPIC

Here's the basic Stamp code if anyone is interested.
Only requires hooking up some cheap relays to the I/O and an switch to sense when the car is staged...

'{$STAMP BS2} 'STAMP directive (specifies a BS2)

'Christmas tree
'This program runs a drag racing christmas tree.
'There is only one staged input, it is assumed that
'staged and prestaged are anded together externally


'Booleans
IsStaged VAR bit
IsStaged = 1

'Inputs
Stage CON 8

INPUT Stage

'outputs
TopYellow CON 9
MidYellow CON 10
BotYellow CON 11
Greenlight CON 12
RedLight CON 13

OUTPUT TopYellow
OUTPUT MidYellow
OUTPUT BotYellow
OUTPUT GreenLight
OUTPUT Redlight

'Constants
LongPause CON 1000
ShortPause CON 500

'Main*********************************** *******************

Start: 'Make sure all lights are off
HIGH TopYellow
HIGH MidYellow
HIGH BotYellow
HIGH Greenlight
HIGH RedLight

DEBUG CR, "Waiting for Not Staged", CR
WaitNotStaged: 'This allows the program to be used as a parking
IF In8 = 1 THEN StartRace 'light. It waits for the car to leave it's parking space
GOTO WaitNotStaged 'before re-arming itself

StartRace:
DEBUG "Waiting For stage", CR
WaitStaged:
IF In8 = 0 THEN Countdown
GOTO WaitStaged

Countdown:
DEBUG "Running", CR
PAUSE 1000 'Wait 1 second
IF In8 = 1 THEN RedLighted
LOW TopYellow 'set Top yellow
DEBUG "Top Yellow",CR

PAUSE 500 'Wait 1/2 Second
IF In8 = 1 THEN RedLighted
LOW MidYellow 'Set middle yellow
HIGH TopYellow
DEBUG "Mid Yellow",CR

PAUSE 500 'Wait 1/2 Second
IF In8 = 1 THEN RedLighted
LOW BotYellow 'Set Bottom yellow
HIGH MidYellow
DEBUG "Bottom Yellow", CR

PAUSE 500 'Wait 1/2 Second
IF In8 = 1 THEN RedLighted
LOW Greenlight 'Set Green light
HIGH BotYellow
DEBUG "Green light!", CR
Pause 5000 'Leave green light on for 5 seconds
HIGH GreenLight

Goto Start

RedLighted:
DEBUG "Red light!", CR
HIGH TopYellow
HIGH MidYellow
HIGH BotYellow
HIGH Greenlight

LOW RedLight
Pause 5000
HIGH Redlight
GOTO Start



[Modified by 427V8, 11:22 AM 11/15/2002]

 

I've actually already got a discrete logic circuit drawn up, I just need someplace to host the pspice file so I can post a link to it. What kind of outputs does one of those stamp chips have? Most decent sized relays take at least 100mA of current to run. For the TTL design, all the outputs need op-amps on them to drive the relays. Is this true of a PLC?

Actually, your code has a (very low-occurance) bug. It only checks for a red light when its time to turn on the green. Remember there's another set of tires coming through the lasers. If the car leaves at just the right time for the back tires to cross the staging laser when the green comes on, you won't get a red light. The only way that I can see to get around this would be to use interrupts. Here's where discrete logic has an advantage. The circuit I've drawn up latches a red light in as soon as it happens.

Hardware engineer indeed...

Actually, if you use a PIC, using interrupts, you could include RTs and ETs. Of course, getting ETs is dependent on having a sensor 1/4 mile away, but you could at least program the PIC to do it.


[Modified by GTLocke13, 1:08 PM 11/15/2002]

 

ok, today i had electronics so i went over GTLocke's schematic with my teacher. He said it was very good but there was a hell of alot easier way to do it, he said just use the stamp chips and when you are done we can burn it on a pic chip. so he hooked me up with a grade 12 student who had just completed his coding unit and we coded the whole thing in 5 minutes! it really was a hell of a lot simpler than all those relays and stuff. and instead of lasers for testing to see if someone leaves early my teacher said we could use infrared stuff.

 

almost forgot, we also randomized it for being a pro tree and a regular tree