Hi guys - Since Its my first post here I'll do a very quick intro. I'm a computer IT tech with an interest in computer projects and case modification. My travels in my latest venture is a HTPC case which I have a very specific need for a LED project so I'm afraid after a quick google around I took to pick on this forum looking for answers and advice.

I've after creating a module which will (hopefully) connect to a standard 3.3v LED header on a PC motherboard to provide a rotation effect LED pattern. I'm not 100% set on the 3.3v but it would make life a little easier for me. Failing that, If I could connect up the existing 3.3v to the circuit to act as a 'on' button and connect something else (maybe 12v since its going to be PC PSU based) to power the actual LEDs etc.

Based on the image above, I want the LED's to move one at a time for around 0.5 delay between moves clockwise around one at a time starting at No. 1 moving from No. 8 back to No. 1 (1-2-3-4-5-6-7-8-1-2-3 etc). I'm not sure if there is something I can get which will allow this type of pattern to be created (once finished) to allow no other interaction required other than providing the '3.3v' acting as a 'on' button.

I want to make it a single sided PCB with surface mounted components as much as my ability will allow. I'm fine soldering 0805 by hand but wouldn't want to go much smaller and i have no experience in double sided PCBs so would prefer to stick to single side. I'm also ok with the etching process (photo board, dev, etch) etc.

I'm afraid I have little to no actual electronics skills. If it turns out this is likely to be very hard for my skill level I might turn to something like an Ardrino but i would like to give this a go maybe learning on the way.

Would someone be kind enough to offer suggestions and if possible links or advice specific to things which would help me get to my end goal. I do offer my appologies for my lack of design skills or understanding coming to you - circuit design isn't really something I've never needed to learn before now

thanks
dave

 

http://forum.allaboutcircuits.com/showthread.php?t=19075

Look here.

 

Based on the image above, I want the LED's to move one at a time for around 0.5 delay between moves clockwise around one at a time starting at No. 1 moving from No. 8 back to No. 1 (1-2-3-4-5-6-7-8-1-2-3 etc). I'm not sure if there is something I can get which will allow this type of pattern to be created (once finished) to allow no other interaction required other than providing the '3.3v' acting as a 'on' button.

Google Knight Rider flasher.

 

Thanks for that. I'll have a read over it in depth when I'm a little more awake.

Lot of information in that thread and even basic schematics I don't really understand so I might look at getting a basic book or guide as I think it maybe out of my reach for the time being.

 

You can use a 555 timer and 4017 (10 outputs) or 4022 (8 outputs) counter for the sequencing part. Run it from 5V or 12V and use a transistor to switch it on and off from your 3.3V trigger. You could just let the timer run and use the transistor to sink the enable pin on the counter. If you want to drive your LEDs at full brightness, you'll need a driver transistor for each or a convenient transistor array such as a ULN2803A with 8 in one IC package.

The 555/4017 sequencer is quite well known and you'll find lots of variations. I think the "Knight Rider" circuit reverses direction instead of straight sequencing so that's not the best example.

 

With a simple MCU in a 14-pin SMD package you can get any multiple patterns you dare create. All you would need is a MCU, eight LEDs and eight resistors, all SMD if you wish.

 

There's a current thread showing the microcontroller approach.

http://forum.allaboutcircuits.com/showthread.php?t=67622

 

Here's a good one, no microcontroller.

3V LED Chaser

Very nice write-up.

 

Is that by our very own Audioguru?

 

Here's a good one, no microcontroller.

3V LED Chaser

Very nice write-up.

You can't get much out of blue LEDs with 3V but the circuit could be adapted to run on 5V..

 

Is that by our very own Audioguru?

I wondered that also. His profile shows from Canada, and most
telling, a quick peruse through some of this person's posts revealed
a dislike for the "lousy old 741..." .

What do you think?

 

Well there's just room for only one Audioguru on this planet.

 

I'll have to look it up, but someone (Electronic Goldmine I think) sells a kit that could easily be modified to do this. It is basically a 4017 sequencer circuit very similar to what I showed in my article. If you go this route I can talk you through the modification, you will still need to solder parts on though.

 

Something like this? but with less LEDs?

http://www.youtube.com/watch?v=W8D2P36XjHg&feature=g-upl

A partial schematic with a few bits and bobs missing.

Mounted on veroboard.

A simple-ish 555 timer dual 4017 decade counter circuit with individual dimmer circuits on each LEDs that give a trail effect. Easier to do with microcontrollers I guess but I don't have any kit for that. I didn't design a 3.3v LED into the circuit as it was always intended to be operated by a manual switch.

This was my first major electronics project (beyond wiring up a few LEDs and expermenting on protoboards) so made loads of mistakes.

 

He only wanted 8, when means he needs to remove two of the sequences off the 4017. It is really easy to do.

If you are interested in PCB layout for a 25 LED sequencer...

25 LED Open Ended Sequencer

How I make PCBs

 

Thanks for those guys, especially the examples. I'm basically looking for as easy as possible to start with to get the inital results and hopefully learn a thing or two on the way. The 3v one look decent from what I'm after - If its easy enough to loose a couple LED's to make it 8 in total and modify values to accept 5v power I might just work perfect.

I'm thinking something like this with a 9pin connector / ribbon on the botton to connect it to the board containing the main bits - I presume I wouldnt cause issues using a shared ground?

Bill_Marsden - If you do end up finding a kit which can be modified that would be perfect as I wouldn't need to search for components etc individually. I would need to modify based on my layout. I think I'm going to end up having the LED's in place on one board which already houses some of the buttons i'm using, then have a ribbon type cable to another PCB with everything else on so the bulk of the circuit isn't taking up the space on the front of the case. Also thanks for the making PCB links - personally I'm a fan on photosensitive board and use a home make UV box with Hydrochloric Acid / Peroxide too. I've not had much luck with toner transfer type methods.

Although I don't understand much of the schematic part or board design it would be nice to learn a little of it during this mini project as i've always made my designs for odd bits in photoshop and never a real PCB design software.

 

I will display the company and the part number when I am on my personal computer. It is very low cost, I think you will like it.

 

very low cost - lol you know me already

If all fails, I'll create it using an arduino but I'm keen to learn a little on the way so if I can learn a few new skills (espcially since I took the time to make a UV box and bubble etch tank) it would be nice to make some 'real' PCB's rather then the stuff I've done already. Here is the simple boards I've made already just to give me button locations etc. This LED chaser needs to live on the long front PCB with the 6 buttons on.

 

Here is the link to the kit.

http://www.goldmine-elec-products.com/prodinfo.asp?number=C4431

It has gone up in price a little since I last looked ($10.40), but isn't too bad.

Your PCB design would work, if I am not mistaken. You would run wires from the kit board to your layout.

If you are starting to make your own PCBs you aren't that much of a beginner.

This is one of the few projects it would be cheaper to make than to buy.

 

Thanks for finding that out for me.

I'll check it out later in more details. I'm UK based so I might see if I can find a Uk source for something similar as I expect postage for jut the one kit would be very high.