Looking for LED/EL wire controller help

Hey all I'm toying with an idea and I need to pick some brains who I hope know wayyy more than I do at this point. What I want to do is control several high out put LED's and several EL-Wires all from the same circuit running off 9V it's been suggested that I look at the PIC

16F84 for this and that's all well and good but I need some suggestions as to the additional parts and layout. The PCB I can do but I'll be honest I'm no circuit designer and this is a little toy type thingy for one of my kids so simple and sturdy would be good as well.

And info will be welcome

TIA

R Morton

Reply to
Master Raven
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Well I have heard a suggestion from an on line site that if I really want an almost truly random pattern I should look at using a "microcontroller running a PRBS (pseudo-random bit sequence) algorithm. That gives much better randomness than any attempt to use multiple separate oscillators, and it's also cheaper nowadays".

Well ok.????? Now does anyone have any ideas as to the controller and or a component layout?

TIA R Morton

Reply to
Master Raven

I don't know what an EL wire is. In fact, I can't make heads or tails out of most of your post.

But, I believe a PRBS is what a linear feedback shift register spits out. You can search the web for "linear feedback shift register" or LFSR.

You don't even need a micro-controller for one. You can build one from a shift register and a clock (and a few logic gates). Hence the name. ;-)

Note that for your purposes, it might be adequate to have one LFSR and conect different LED's to different bits on the LFSR. You wouldn't need multiple LFSR's.

HTH!

--Mac

Reply to
Mac

Yes, it is somewhat clearer.

I think a LFSR will work. Go google for LFSR circuits and see what you think.

So, if someone were to give you a schematic of the LFSR part, and point you to the logical outputs which toggle in a pseudo-random fashion, could you do the rest of the design?

BTW, how many outputs do you actually want, and how fast do you want them to change? For example, would 2 Hz be a good rate? This would mean that twice per second at least one of the outputs would change.

--Mac

Reply to
Mac

Hey Mac, Sorry if my post is not totally clear, it is to me but then I posted it :) Ok what I want to do is turn on and off several high out put LED's the really bright ones but I'm not talking the 5W jobs just the super bright water clear LED's At what appears to be a random rate. Also I want the circuit to also control what is called EL-Wire or Electroluminescent Wire think of a florescent tube but it's a wire. So what I'm looking for is a schematic for a controller that can handle several outputs either directly (in the case of the LED's) or via miniature relays for the EL Wire. Is that clearer I hope so, any thoughts or advise. I'm asking here because I can do the PCB layout and the building but not the actual design.

TIA R Morton

Reply to
Master Raven

Thanks Mac,

I'll do the search I followed the other offered link but it only lead to a description of what an LFSR was.

As to the Schematic aspect I'm pretty sure I can, I mean normally I can but I would have to see the schematic first. Single or double sided boards are not a problem I do things in a quasi old fashioned way of doing the work in Corel Draw or Illustrator and then would just photo etch the pcb or might have it laser cut if really detailed and with tight register.

As to the out puts I'm flexible at this point say 5 LED's and 5 EL wires. if it looks good and actually works I might look into expanding it. And seeing as the EL wire uses an inverter I would use dual inverters to reduce the bulk and just place the relays for them between the inverters and the EL Wires themselves that way at any point an EL Wire can light and will not have to wait for a possible slow inverter.

For the flash rate I would thing 1Hz or lower would make for a nice color change and not be to strobe like.

Thanks again

Richard

Reply to
Master Raven

Just a recap. Suggestions so far received include.

"microcontroller running a PRBS (pseudo-random bit sequence) algorithm. That gives much better randomness than any attempt to use multiple separate oscillators Using a PIC 16F84 And building a LFSR circuit. These are all great but none have suggested where I might find a schematic employing any of these devices.

I have googled for LFSR circuits and again got loads of info about LFSR's and theories employing them but no actual schematics. Only software references or code information.

Reply to
Master Raven

Just changed my default search engine in Firefox from Gurgle to wikipedia, by mistake, but

formatting link
was the first hit, a good one

Think I've made a good mistake

martin

Reply to
martin griffith

Ok guys I've looker for stuff as advised but seem to come up dry. so it's back to my old love circuit bashing :) attached in the pdf is a circuit pretty simple but I've added a couple of parts I need to trip a high voltage el wire compoenet so I need some one to look over the file and see if I'm way off base here or will it work? I'm hoping I can trip the relay with the current that is intended for the led. That way I can turn on led's and el wire from the same device.

Reply to
Master Raven

I'll try describing this in words. Not sure I have time to make a real schematic.

You need a 10-bit D flip-flop. Each D flip flop has an input (D) and an output (Q). In most cases you want to connect the output to the input of the next flip flop. For example, you want to connect Q1 to D2, and Q2 to D3, etc.

I think this part, which has 10 D flip-flops on it will work:

74AC821

There are a variety of parts that are 74[something]821. Almost any of them will probably work.

For D1, you need to do something different. You want to hook up Q10 xor Q7 to D1.

You will need an xor gate for this. The 74AC86 should do it. Or

74[something]86.

You will need to regulate the 9V down to 5V. Try a 7805 for this. Tie the unused inputs to ground.

You will need a clock. You can design a clock with a Schmitt trigger inverter, a resistor and a capacitor. A Schmitt trigger might be the

74AC14. The AC could be something else, just like the other parts. You can experiement with resistor and capacitor values. Maybe 100 K and 10 uF to start with. To go faster, use smaller resistors or smaller capacitors.

There is one other issue, which is that LFSR's can get stuck if they ever get into a state where all bits are zero. You either have to detect that state, and force one of the bits to 1 when it happens, or provide a push-button which forces one of the bits to 1, or something. Probably this can be done with a pushbutton and one of the extra XOR gates.

Let me know if you need more guidance. Or maybe you can try to draw a schematic and post it, somehow, then people can provide corrections or suggestions.

Q1 through Q10 are your logic outputs. Many logic families can drive an LED (with a suitable resistor in series). So you could hook your LED's up to these outputs directly.

That's all I have time for at the moment.

--Mac

Reply to
Mac

Ok guys here is something I've come up with that may not give the randomness I'd like but all I have to do is scatter the outputs so they do not appear as a non random sequence. what I'm wanting to do is replace some of the led's with a relay using the trigger to trip the relay. Now am I totally off base here or is there a better way to do this. Right now well this week I just want to get something going that I can run tests with. so please look over the attached PDF file and let me know.

Regards R Morton

Reply to
Master Raven

test again

Reply to
Master Raven

Reply to
Master Raven

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