i need to make a bar that has about 25 small, christmas-light sized bulbs on it (led or regular) that light up in an oscillating pattern---like a pong ball going back and forth between two paddles. i'm not too experienced with this but i'm sure i could solder it together if i had a how to book or something. i wanted to mount the bulbs on a wood board in a straight line, and have some sort of device that could control the speed the lights go back and forth.

does anyone know a professional i could talk to or where i would/could go with all of these questions? hopefully someone in town at like a home depot or best buy, althought those don't seem like perfect options.

thanks.

8/24/2010 11:37:03 AM

OK, oscillating was the wrong word. i just meant back and forth.

8/24/2010 11:39:44 AM

You mean something like the KITT car lights in Knight Rider?

8/24/2010 1:33:36 PM

http://zedomax.com/wiki/Zedomax_DIY119

Probably something like that. I googled "Christmas Lights Controller".

8/24/2010 1:43:14 PM

yes, a lot like kit.

i'm trying to build a homemade EMDR machine. My therapist was charging me $65 a session for this. I can make one myself, i'm purdy sure, and use it more often than once a week.

[Edited on August 24, 2010 at 2:47 PM. Reason : .]

8/24/2010 2:38:13 PM

I did a google image search, and it seems they can use LEDs as the light sources. If so, then this is a snap. I could build and program the circuitry needed in just over an hour. Wanna pay me?

8/24/2010 5:05:34 PM

You can find plans online for building and programming your own light bar like the one in Knight Rider. I saw them earlier when searching around, but I didn't save any links.

8/24/2010 6:31:24 PM

Even though this is Tech Talk I'd still like to know what you are going to EMDR therapy for

8/24/2010 7:10:44 PM

like this?

http://www.neurotekcorp.com/eyescan.htm

8/24/2010 7:38:14 PM

Quote :

"I did a google image search, and it seems they can use LEDs as the light sources. If so, then this is a snap. I could build and program the circuitry needed in just over an hour. Wanna pay me? "

Program?

It's overkill to use a microcontroller for this.

8/25/2010 12:10:48 AM

^ I dont necessarily think its overkill. Atmel's are so cheap now (around $2 for an appropriate AVR), also reduces the amount of external components required.

I think its just a matter of preference.

8/25/2010 8:38:50 AM

^^ I am quite curious what your design would be that makes a $1.90 atmel overkill?

8/25/2010 1:03:05 PM

heh, I saw that comment earlier today and came back here just now to post just that. I'd like to know what design he has in mind that is simpler.

8/25/2010 10:21:02 PM

I was thinking cheaper, but I guess it would only matter if you're trying to make 10,000 of these.

8/25/2010 10:31:35 PM

And that circuit would be....?

8/25/2010 11:06:57 PM

ha are you joking? You think a microcontroller is the cheapest way to do this?

[Edited on August 26, 2010 at 12:02 AM. Reason : simple decade counter if youre serious]

8/25/2010 11:59:57 PM

We should make this a competition. Who can do the design for the cheapest that still meets the spec. I think you're cost is going to get swamped implementing the logic to make the light go "backwards" (rather than wrap around). A micro controller can do both. Not to mention he wants 25 lights. A micro + a mux is still going to be as cost efficient as multiple 4017s.

8/26/2010 7:49:10 AM

ill join the no micro controller but the classic 555 timer team just for kicks. lol

[Edited on August 26, 2010 at 8:12 AM. Reason : .]

8/26/2010 8:12:39 AM

I didnt think a 4017 could source enough current for LEDs directly off the outputs. Can it?

If it can't you've added a transistor array as well to the design. Throw in some logic to involve flipping directions, and I think you've got too high a component count/cost compared to an all-in-one micro.

The atmel's have built in clocks, can source the current directly off the i/o pins, and have some benefits above a pure logic based circuit.

I would imagine there has to be some science behind this therapy, which dictates the cycle rate, as well as how long each light is on, what the dead time between lights is, etc.... even if its just measured in milliseconds.

With the logic circuit, you are making some assumptions like:

- each light is on immediately following the previous one
- each light is on for exactly X number of clock cycles (which involves even more circuitry if X <> 1)
- the pattern doesn't change, and he would never want to change it.

Not intending to start a war, but it's been a long time since I've gotten to talk electronics with anyone, so I'm loving it.

8/26/2010 8:27:16 AM

we're going to connect a zener to an NPN base as our power supply as well. just to keep it CHEAPZ.

what mux are you going to use? how many? how does it compare in price?

this DEMANDS a 555.

8/26/2010 8:44:41 AM

We should hook a 555 up to a microprocessor as the clock, and use one of the i/o pins on the micro as the clock for the 4017s, just to piss everyone off.

8/26/2010 7:10:24 PM

Quote :

"We should make this a competition. Who can do the design for the cheapest that still meets the spec. I think you're cost is going to get swamped implementing the logic to make the light go "backwards" (rather than wrap around). A micro controller can do both. Not to mention he wants 25 lights. A micro + a mux is still going to be as cost efficient as multiple 4017s. "

That could be interesting, but we'd have to solidify the parameters like the things Wolfmarsh is saying.

8/26/2010 8:00:03 PM

^^ Brilliant! Vary the light duration by varying the 555 clock, in the sub 10Hz range.

8/28/2010 4:59:57 PM

i'm doing emdr therapy for obsessive/compulsive disorder.

and there needs to be a speed control--that affects the strobing speed and how fast the dot (light) appears to be moving back and forth.

i found a big electronics/lights supply place here in knoxville, but they didn't have a clue as to how to help me out. they said i needed a parts list and some directions (offline) on how to build the thing. I would just buy the one that neurotech makes but the thing's off the chart expensive.

[Edited on September 21, 2010 at 4:53 PM. Reason : .]

i mean, first off. i would need a piece of hard plastic about two feet long, drill holes to fit in the leds. hot glue them in place. i don't know where to go from there though. gets all technical and it matters how everything goes together i'm sure.

[Edited on September 21, 2010 at 4:54 PM. Reason : .]

[Edited on September 21, 2010 at 4:56 PM. Reason : .]



[Edited on September 21, 2010 at 4:56 PM. Reason : .]

9/21/2010 4:49:27 PM

So $430 for the cheapest model?

A competent EE with mcu experience and the parts available could do the PoC in half a day.

9/21/2010 5:45:18 PM

so do you just sit there and stare at it?

up until you mentioned the speed control aspect, it sounded like you could just make an animated gif and put it up on TV

9/21/2010 6:17:18 PM

Quote :

"up until you mentioned the speed control aspect, it sounded like you could just make an animated gif and put it up on TV"

If you have a widescreen or big enough monitor, one of us could write you a program on the PC that would work.

The quoted idea is freaking brilliant.

9/21/2010 8:29:00 PM

they have the animated version for your computer available online, but it's really really chinsey and they charge over $100 for it. personally, i like the lighted version but it's probably a lot more complex.

yeah, you just stare at it. the idea is that you hold an image of whatever your trigger is in your mind and the side to side motion helps your brain better process the trigger, so you can relax.

9/22/2010 12:09:29 AM

Something like this? The parts to do this cost well under $10, and it looks like the sort of thing you're going for. It would easily scale to more and/or bigger LEDs, and controlling speed and brightness is fairly trivial.

9/22/2010 10:54:31 AM

so the parts would only be $10? that's awesome. that's exactly what i need pretty much. just more leds on a longer strip with a speed control.

9/22/2010 1:42:47 PM

As has been pointed out in this thread, however you do it, the parts are cheap. Putting them together in a package for you takes labor.

9/22/2010 3:41:16 PM

Being a prototyped circuit, that omits a couple things, but to make it a decent "finished" product requires very little else.

Microcontroller ~ $2
Every 8 LED's requires one IC driver, so three is ~$1.50
5mm LED's are as little as .20 each, depending on quantity purchased, so 24 is ~$5
Various passive components would be about $3
Buttons or potentiometer to control it would be ~$1

Throw in $4-5 for wire, protoboard, IC sockets, and other misc. assembly items, and you're looking at a base cost of around $17 to build a controllable 24 LED strip. Figure shipping on top of that, on the order of $5-7.

If you want to design the enclosure/presentation, I can help you with the electronics part. You could probably meet your basic requirements for under $20 worth of parts and shipping costs without any trouble. Designing and constructing the enclosure would add as much or as little cost as you are willing to spend, since it's pretty open-ended.

9/22/2010 4:50:31 PM

okay. is this some BS?

the warehouse i went to in town was charging $2.43 for a pack of 5 green .5 mm LEDs. manufactured by MODE electronics. 30 of 'em cost me 16.50.

9/24/2010 2:51:42 PM

For electronic parts, you should buy in bulk online.

9/25/2010 12:22:23 PM

http://wall.elnormo.net/how

If I had the time and patience I would do something like this.

9/25/2010 1:02:01 PM

got the 30 leds mounted on a wooden yardstick. price of project so far: $20

i need a parts list of the rest of the electronics i need to do the programming, wires, and whatnot!

9/27/2010 11:16:45 AM

Ouch. You got raped on the LED's.

Also, if you're going to use shift registers (I can't think of better way, actually), you should have even multiples of 8.

[Edited on September 28, 2010 at 12:37 PM. Reason : .]

9/28/2010 12:31:47 PM

Is this still being developed?

10/11/2010 10:06:38 AM

I did it for pay. Used a single 40pin DIP atmel, so there was no need for off-chip circuitry beyond two potentiometers, just solder the wires to the chip and you're done. I did put the chip on a protoboard I had lying around, just to make soldering to the chip easier.



[Edited on October 11, 2010 at 5:33 PM. Reason : img]

10/11/2010 5:30:00 PM

Im glad someone from the micro camp did this. Much easier implementation.

10/11/2010 5:43:47 PM

Nice, I guess you have 32 LEDs you're able to drive with PA-D,0-7, right?

10/11/2010 5:44:39 PM

Oddly, no. The customer wanted it to drive exactly 29 LEDs, so not all of PA is used. PA pin 7 is actually an input to the Analog to Digital Converter which is used to read the "Cycle Speed" potentiometer. The other potentiometer is used as a variable resistor in series with the LEDs, which all share a positive common, with the chip providing one-hot active-low.

I was using a cheaper chip than I am used to, so I was unable to use the watchdog timer as a timing source, which means the internal oscillator and a timer are kept running while the processor is asleep, waking up every 20ms to recheck the ADC and, if necessary, change the LED positions.

#include <avr/io.h> //iotn26.h for ATTINY26
#include <avr/interrupt.h>
#include <avr/sleep.h>

EMPTY_INTERRUPT(TIMER0_OVF_vect);


short get_ADC(void) {
  		ADMUX = 0x47;
		ADCSRA = 0Xd2;	// 11010010	single trigger 	clear
		while(!(ADCSRA & 0x10));
		ADCSRA = 0Xd2;
		return ADC;
}
#define state_max 0x10000000

/* Main function */
int main(void)
{
	TCCR0 = 0x02;	// /64
	TIMSK = 0x01;	// overflow interrupt
	DDRA = 0x7f;
	DDRB = 0xff;
	PORTB = 0x5a;
	DDRC = 0xff;
	DDRD = 0xff;
	unsigned long state = 0x1;
	char dir = 1;
	unsigned short read = 200;
	unsigned short max = 200;
	unsigned short count = 0;
	set_sleep_mode(SLEEP_MODE_IDLE);
	sei();
	while(1) {
		count++;
		if(count > max) {
			count = 0;
			if(dir) state = state << 1;
			else state = state >> 1;
			PORTB = ~(state & 0xff);
			PORTD = ~((state >> 8) & 0xff);
			PORTC = ~((state >> 16) & 0xff);
			PORTA = ~((state >> 24) & 0xff);
		}
		if(state == 0x1) dir = 1;
		if(state == state_max) dir = 0;
		read = get_ADC();
		if(read < 100) max = read >> 4;
		else max = (read >> 3) - 8;
		if(read > 512) max = (read >> 2) - 93;
		sleep_enable();
		sleep_mode();
		sleep_disable();
	}
	return 0;
}

10/11/2010 6:53:42 PM

this says it's free, didn't try downloading though

http://download.cnet.com/EMDR-Aid/3000-2129_4-10863922.html

10/11/2010 7:47:09 PM

Quote :

"Something like this? The parts to do this cost well under $10, and it looks like the sort of thing you're going for. It would easily scale to more and/or bigger LEDs, and controlling speed and brightness is fairly trivial. "

The parts may be $10, but it's using an Arduino microcontroller, which runs about $25 on its own... but it's a really good investment, since it's reusable and really REALLY REALLY easy to program.

10/11/2010 10:15:54 PM

Dude, it says right on the video it is a TI MSP430. It says IN the video it is a TI MSP430. You can get the entire board for $4.30 + shipping direct from TI.

10/12/2010 7:21:08 AM

My mistake.

10/12/2010 9:57:15 AM

As an added advantage, TI will send you more chips for free through the sample program, so you can buy the board once(which comes w/ two mcu's) then get as many more as you need for various projects.

The MSP430 there is much less capable than the Arduino's Atmega328's, but it runs on way less power. It's excellent for battery-powered devices.

10/18/2010 2:27:11 PM