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3V LED Chaser project


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Hi Guys,
The project is here:
I have a pic of my Veroboard layout. It has 47 (!) trace cuts which takes my drill-press about 2 minutes to do. It has 21 jumpers, a few under the ICs, that takes me abut half an hour to cut, bend and solder. It takes a while to solder the rest of the stuff on the board. See that I am using pieces of IC-socket to plug-on-to two LEDs that have their wires inside the box where it is crowded for soldering.

I had to be careful drilling the CD for the LEDs because it is fragile, my 1st one shattered all over the place!

I drilled the front of the box for the two LED holders to protrude through and routed-out the PCB support grooves at the sides to allow space for the pots.

I bought log (audio taper) pots for brightness controls and linear ones for speed control, but the linear ones were actually log type (marked wrong) so the full speed adjustment ends-up in the maximum 1/4 rotation of the pot.

I am busy making a bunch of these things for family and friends.

Corrected Nov.12/04


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Hi Guys,
I am sorry that I made a boo-boo on my Veroboard layout and pic. I made another project and it didn't work!
Besides getting one AA cell backwards (darn Japanese battery cells with tits on both ends), I discovered that I had one extra trace cut (between pins 2 and 13 of the 74HC14).
I have corrected my layout and pic, above.
Sorry for any inconvenience.

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Hi Guys, (And warm greetings to the ladies amongst us)

Here's a pic of two 3V LED Chaser projects. It was difficult to snap a pic at the moment when both are lighted (even though they were chasing at high speed).

Between them might be the next project that I post, it very slowly dims and brightens its three colours, each at a slightly different rate. I used 30 degrees angle Ultrabright LEDs that make a magnificant display of 16 million colours on the ceiling. Every 10 minutes all LEDs are sync'd and are at their brightest, producing white, then 10 minutes later they all dim to nothing. All colours appear slowly in between.
The circuit uses a bootstrap technique so that the LEDs dim logarithmically, like our vision. At first I tried linear ramps, like the project that we already have, but it doesn't dim very much.


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Thanks Dazza,
Sure you can make and sell these thingies, I didn't patent anything. I just design them for fun and the challenge of making them work well with a power supply as low as 2V.

My only condition is that if I ever visit down under, you buy the 1st round of Guinness. ;D ;D

[move] :'( :-* :-\ :-X :-[ :P ::) ??? 8) :o :( >:( ;D :D ;) :)[/move]

How can I make these faces loop vertically, like my LEDs?

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Thanks Ante,
I'm making a bunch of these 3V Chasers. I gave one to my (grown up) daughter for her birthday yesterday, and she says her friends will want them too. My friends and rest of my family also want them.

In my pics is my new Taiwan copy of Veroboard. It seems to be made of compressed dung, or similar stuff. It certainly isn't epoxy-glass and stinks during soldering. I hope it doesn't warp too much.

What happened to the division of Vero that made Veroboard and other prototyping things? I liked the "real stuff" and know that Brits would never use dung. I viewed their "new" website a few months ago but now it's gone.

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Hi Ante,
A big joke over here was, "What are we going to do with all those free ISP CD Roms?" I found a use for them.
While searching in my son's room for his digital camera, I discovered that his stack of virgin CD-Rs or CD-RWs create a very intense rainbow reflection effect, so i "borrowed" a few. I'll use them next. They are darker than the ISP's ones and the label side has a pleasant diffused reflection. They are slightly transparent so I hope the LED wiring doesn't show through.

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Hi Dazza,
You might have a big problem with availability. The various manufacturers all have different codes, but my ST-Micro datasheet lists the "M" suffix as a surface-mount package. Double-check with Farnell. Texas Instruments further confuses things because some of their 74HC ICs have a CD prefix and SN for others.

Up here, we get to choose the supplier and the manufacturer of ICs. I used Digikey for a recent order, but they ran out of TI ICs so I settled for slightly cheaper ST-Micro ones.

Won't TI send you free samples? Tell them your plan.

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Your project is great, save me from thinking on how to flash a bunch of LEDs with 2 AA cells...
I will build my own too, not for $$$, but for a special gift to my girlfriend..... ;D

The IC with prefix CD40xx may not work at 3V but the 74HC40xx should be work fine with 3V..... I gotta check this out.

Anyway thanks!! ;D

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Nothing is simple is it ;D, I'll send Farnell an e-mail.

Ante's comment that they would be popular for Christmas,I think is true :). That doesn't give me much time.

I can see the scenario, I put a dozen out to test the market, and I find everyone wants one, and then I can see myself going mad trying to keep up, with no experience soldering in surface mount chips ;D ;D,

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Thanks Trigger,
I am using 74HCxx ICs that are guaranteed to supply a strong output current with a supply of only 2V, which is what the 3V battery will be at the end of its life. Ordinary CD4017 ICs are guaranteed to supply hardly any output current with a supply of 3V, and probably don't work at 2V.

Hi Dazza,
Ask TI for a list of their distributors down under of the IC. With both them and you asking Farnell about it, Farnell might decide to supply it, or TI will give you samples.

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Hi Guys,
I drilled a CD-R to make another chaser and Disaster!
My workbench and I got covered in little bits of rainbow coloured metal, and the metallic film of the CD-R easily peeled off starting at the holes. A piece of tape removed the remainder of the metallic film.
I didn't know that the metallic film on a CD-R is not protected by a plastic layer like on ordinary CDs and CD-Roms. I better be extremely careful with the CD-Rs that I use for storing pics and programs.
I drilled another free CD-Rom from an ISP and its metallic film is inside a layer of plastic on both sides, well protected.

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Hi audioguru,
have you thought of trying a hot metal spike to melt a hold through the CD, maybe a high-powered soldering iron with a large TIP .

I have an idea that might be interesting to try. If you got a few pieces of Dow, and placed them flat in the shape of a cross, then place the CD on it and put it in the oven. It should distort evenly creating an interesting effect.
You might want to drill the holes first though.

Warning oven baked CD's are not edible ;D

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Hi Guys,
You know what a traffic accident scene looks like on a highway at night? That's what my place looks like with my 3V LED Chaser projects flashing all around!

I was thinking about using the very expensive Lithium AA battery cells that I got as free samples for longer battery life, but the 1st project that I made with AA alkaline cells about 3 weeks ago is just as bright as the newest ones. Ordinary alkaline is fine.

I still have the CD-Rom where its metallic coating came off. It is clear with a green tint and has a rainbow reflection like a regular CD. My wifey says to paint it with metallic spray paint. I'll let you know how it looks.

I changed the Veroboard layout a bit so that the ribbon cable wiring to the LEDs is neater. I reversed the wiring for LEDs 1 and 2, and 9 and 10.

I finally found 1M linear pots for the speed controls. They have switches that I have to cut-off, and the threaded mounting part is loose requiring gluing with epoxy. They control the speed very smoothly.

I am trying to take a time-lapse pic showing the PWM pulses by moving the project or camera. I'll post the pic when I get it right.

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  • 2 weeks later...

Hi Guys,
I just finished building another 3V LED Chaser, but this time I used Ultra-bright BLUE LEDs. Of course since they need 3.2V to light, I had to use a 6V battery of four AA alkaline cells. I used the same box, with 2 cells inside like before, and the other 2 cells top of its lid, secured with the same screws. I changed the current-limiting resistor (R7) to 120 ohms and the transistor's base resistor (R6) to 1.8K ohms. A 6V supply is no problem for the 74HCxx IC's because their max is 7V.

How does it look? WOW! Extremely bright blue flashes that look like the strobe lights on snowplows. (Or the flashes that you see in front of your eyes when a coconut falls on your head from a tree, if you don't have snow). ;D

The next one will have Ultra-bright GREEN LEDs.

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Hi Guys,
I knew it would happen.
When my daughter saw my "6V" Ultra-bright Blue LED Chaser, she liked it and took it to match the red 3V LED Chaser that I gave her a while ago. Her friends want the red ones and will probably want the blue ones too.

Luckily, my local electronic surplus parts store has Ultra-bright LEDs. I bought a few blue and white ones and they are very good for a low price. I'm going to take a 9V battery with current-limiting resistor and 2-pin jack over there to match a bunch of LEDs that I'll buy cheaply. I'll try for a quantity discount like Digikey gave me.

I guess the "6V" Ultra-bright Green LED Chaser that I am making will become another blue one, and I'll make a green one later.
I'm not running out of CD Roms to mount the LEDs on. I keep getting the free ISP CD Roms in my newspaper.

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