Programmable IR LED Flasher Circuit -- How to Build?

Whine, whine, whine! This thread belongs on news:sci.electronics.basics which was created for people who don't have any clue as to what they are doing.

--
Service to my country? Been there, Done that, and I\'ve got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida

Now that's helpful. At least I now know what it's based on and can now research and read about the device to decide whether I want to mess with it or not. Sounds interesting, so it's definitely worth looking at.

Thanks for the help.

{yawn}

This thread belongs on

Wow! You too? How smart you are! You win the prize. It's a steaming hot cup of SHUT THE FUCK UP. Congrats.

Nice quote... the military is full of mediocre troopers. I bet you were one of them.

--
No, all you have to do is be a thief and think smugly about how you
managed to rip off someone else\'s design by enlisting the help of
well-meaning strangers.

First of all, it is often hard to build "one of" and make it for less than a commercial unit. Even metal boxes are $10 these days. So I would build it only if the item were superior, or you want to learn. I generally build things that can't be bought.

Now how many patterns do you really need? Lets say the pattern lasted 4 seconds. In any one second period of that 4 seconds, the led could be one or off. So enumate the possibilities, with each digit below representing one second period:

0000 0001 0010 0011 ... 1111 For example, 0010 would be two seconds off, one second on, then one second off.

So there are 16 unique cadences. One solution would be to build a state machine that counts as follows:

1000 0100 0010 0001

Now each digit here would be followed by a switch that would enable the LED. You could do this with a shift register, but the problem is to make sure you only get one "one" in the register. A counter followed by a one of N decoder would work. You could also get 4 D FFs and make a state machine

Present| next

0001|1000 0010|0001 0100|0010 1000|0100 all other states are "don't care"

Plug these into a k-map and reduce the logic.

That is much harder to do and would probably require a microprocessor.

A boost converter takes the AA cell voltage, say between 2 and 3V, and boosts it to a voltage where logic would work. In the case of this design, you may be able to run the logic from 2 AA cells if it is CMOS, since the speed is very slow. However, the LEDs need more than 2V to turn on. Maybe 3 AA cells would do the job, but it doesn't give you much head room to regulate the current in the leds. If the LEDs are in series, you need considerable voltage, though plenty of companies make chips for LED flashlight that could be used.

I really suggest you look at my other post and do the k-map. Actually, that is Karnaugh. You would be amazed at the number of EE grads than can't design simple logic with a k-map. This would be a good learning experience.

I eyeballed this page, and it looks reasonable. [You can never tell with wiki though...]

I interviewed MIT grads that don't know the insides of a CMOS logic gate as well as not being able to do K-maps. There are sophisticated silicon compiler schemes using VHDL, but geez, in mixed-mode designs, you have to be able to design simple logic.

--
From his more recent posts, where he\'s stated that he has a big
budget to devote to this project, and also from his earlier posts
where the tone was one of some urgency, it seemed to me that he was
trying to get some free design (without disclosing that that\'s what
he was looking for) in order to either compete with or usurp what\'s
already out there.

In my book, that\'s cheating.

I was an engineer, and received a commendation for my work. I bet you were a WAC.

--
Service to my country? Been there, Done that, and I\'ve got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida

Wow! thanks, but I don't want to take your lunch from you, just to pour it over your head. One thing is for sure, you wouldn't even make Booby prize.

Why is it all the foul mouthed morons post with a Gmail account?

--
Service to my country? Been there, Done that, and I\'ve got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida

Hello kpkilburn,

This link:

has an interesting product.

I work with microprocessors everyday.

I see in the Picture on the link, that the device uses a 2 Microchip

8-pin chips.

I have used just about every 8-bit single chip processor ever created.

So I have lots of chips laying around. I do have 8-pin Microchip and

8-pin Atmel, Motorola, and TI devices around.

With what I have read, there is enough information available for someone like me to develop.

I will not assume what talents you have to bring to a project like this.

If you are a web programmer, I will give you credit that you understand compilers and editors.

But what is your experience in working with microprocessor hardware. Timers, I/O ports, Flash programmers ,etc.

As a learning experience you will have a load of fun developing this type of project.

I will not start a religous war about what processor to chose.

Any one of them will do the job.

Please let us (me at least) know how you are doing.

What ever you decide to chose, post again if you would like some help.

again Good Luck

donald

Who?

-- Paul Hovnanian mailto: snipped-for-privacy@Hovnanian.com

------------------------------------------------------------------ APL is a write-only language. I can write programs in APL, but I can't read any of them. -- Roy Keir

A microcontroller provides the equivalent of these components in software. Since parts count is the major factor in a product's cost, its cheaper to do it in s/w.

--
Paul Hovnanian     mailto:Paul@Hovnanian.com
------------------------------------------------------------------
Windows tip #248: add BUGS=OFF to your registry.

Mine too. I'd missed the earlier posts. Big budget = project is important to someone = do if able, if not able then retain skilled professional.

Learning.

. . . It's a field programmable unit, but this is a good approach and would probably accomplish the same thing. For practicality, this works.

I'm pretty familiar with K-maps, so maybe that's the way to go. I just wanted to know how it worked -- if it's a microcontroller, then fine. I just really wanted to know what was inside of it. It's like having the schematics for an Atari 2600 or TRS-80. I'll never build one and try to sell it as my own, but it's very interesting to look at them and see what made them work.

I like your idea of just making different patterns. I wouldn't need more than 7 or so assuming it would be used by 7 different units.

Thanks.

I'm familiar with K-maps, so I'll go back and look at that.

My preference.

[snip]

This MIT grad knows both ;-)

...Jim Thompson

-- | James E.Thompson, P.E. | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona Voice:(480)460-2350 | | | E-mail Address at Website Fax:(480)460-2142 | Brass Rat | |

| 1962 | I love to cook with wine. Sometimes I even put it in the food.

--- Here's the reply I got, via private email (after the asshole wrote "I want no part of your perverse little world."):

I see now why you were such a smartass. You were afraid. You were so concerned that someone was "cheating" and was going to get something free from you that you completely missed the point and ran your mouth. FYI, it's nothing more than a personal project with the added benefits of:

1) saving a trivial amount of money though that's not really an issue for me since I control millions 2) training my guys on soldering and assembly tasks, plus giving them something fun to build 3) just knowing how the damned thing works

I'm not in the industry and quite frankly couldn't care less about competing or usurping what's already out there. I don't have a budget dedicated to paying arrogant engineers to design stuff. I simply purchase what I need to do my mission.

Next time, before you start running your mouth, get a clue. You're not the smartest guy in the world and when someone asks something, it's usually exactly what it was intended to be -- a simple question with no hidden agenda like you suspect!

I have no tolerance for people like you -- people who think that they're somehow above everyone else just because they get paid "big bucks" or because they're adept in their field. Here's a dose of reality for ya -- you're replaceable, so get off your high horse and act like a f***ing human being for once in your life.

I don't like dealing with these loons in private, so I'll reply here in the open:

First, loon, If you ever email me again without my permission I _will_ make it my business to inform your CO that I consider your unwelcome emails an invasion of my privacy. Also, I'm sure that using Government resources for personal business is frowned on by the military.

This _is_ where you're posting from, isn't it?:

OrgName: 1112th Signal Battalion OrgID: 1SB Address: Directorate of Information Management Address: ASQNA-BRG-RI Address: Building 1-1434 City: Fort Bragg StateProv: NC PostalCode: 28307-5000 Country: US

NetRange: 147.239.0.0 - 147.239.255.255 CIDR: 147.239.0.0/16 NetName: BRAGG-GW2 NetHandle: NET-147-239-0-0-1 Parent: NET-147-0-0-0-0 NetType: Direct Assignment NameServer: NS01.ARMY.MIL NameServer: NS02.ARMY.MIL NameServer: NS03.ARMY.MIL Comment: RegDate: 1991-07-24 Updated: 2005-10-11

RTechHandle: DES90-ARIN RTechName: Stetter, Dennis E. RTechPhone: +1-732-532-2701 RTechEmail: snipped-for-privacy@mmcs.army.mil

OrgTechHandle: BS260-ARIN OrgTechName: Starnes, William OrgTechPhone: +1-910-396-4223 OrgTechEmail: snipped-for-privacy@bragg.army.mil

# ARIN WHOIS database, last updated 2006-09-10 19:55

As far as giving something away for free goes, on these groups over the years I've given away probably thousands of designs including schematics, bills of material, software programs, mathematical solutions and God knows what all else, so If you'd have checked my posting history first, instead of running _your_ mouth you could have saved yourself the embarrassment of getting busted for talking out of your ass.

Initially you said that what you were looking for was to find out how the things worked, but now it's about saving a trivial amount of money, training your guys up, finding out how the things work, and (as I recall from an earlier post) building 7 units because that's all you need for your mission.

Something sure has changed from the pleas for help from an innocent seeker of knowledge with no hidden agenda...

Also, if what you wrote above: "I simply purchase what I need to do my mission." is true, then why don't you just do it? The amount of money you're gonna cost the taxpayers by f****ng around trying to build the things is going to be a _lot_ more than if you just bought them outright. What are they, like $80 a pop or something? That's not even $600. Down in the noise, I'd think, for someone who "controls millions",LOL! As for the rest of your whining, blow me.

-- John Fields Professional Circuit Designer

I have no idea what your background is, but I just cringe when every solution to a problem is a microcontroller. As a mixed-mode chip designer, it is required to know how to build simple logic. I just wonder where the next generation will come if everyone throws a uP at the problem.

There was a situation where two different groups had projects that required multi-master SMB interfaces. One was designed with VHDL and some sort of compiler, while the other was hand crafted by me. I ended up designing a very crude uP with about 6 instructions. It was all designed by hand using K-maps. When the dust settled, my design was 16 times smaller. [FF in that design required extra inputs for testing, which put it at a disadvantage. Still, the design was bloated.] Some mixed-mode chips would never get off the ground if every one needed a PIC on-board.

You won't regret designing the logic yourself. You can use dip switches to set the code. (quite cheap). Note that if you feed a counter directly to a decoder, it will probably glitch. For your application (human vision), this is no problem. I haven't designed with off the shelf logic in year, but if the decoder has an enable line, you may be able to do the design so that the LEDS are not enabled while the counter is switching. I wouldn't throw much logic at this problem, but if it can be done with a bit of gate delay (inverter strings to the enable pin), it might make viewing the design on a scope or logic analyser (debugging) more pleasant.

One level of sophistication higher would be to bag the funny visual codes and pick a different frequency for each user. Then design a circuit to detect this frequency. Night vision is pretty slow, so I would see what speed it could handle first.