I'll Pay Cash for a Minor Circuit Design

Cool...and old mac learned something..never heard of PIC before. It's been a while since I did any chip level design.

 

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how would you carry out the specs in the OP with an analogue design?

in a straight binary counter the outputs in decimal are 0,1,2,3, .. .
in a truncated counter the sequence is irregular as in your example.

 

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Well, I'm not actually putting a patent on the circuit itself. Only the configuration/design and application of the product. I may even sell these like hot cakes without any patent.

How much would it cost to build a single unit that you have described here?

 

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Still waiting for your quote.....

 

Sorry, I've been celebrating some good news (got a position in an awesome company).

I've PM'ed you.

 

555! Could do it the analogue way with one of these, but with a processor (small cheap one) it's so easy to make pulsing, fading, flashing, colour sweeping effects. A friend on mine has written a good PWM led driver for exactly this purpose (its freeware) which would save me around an hours programming time.

 

how?

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They still make 555s? Wow!

 

The first thing you tend to make in England in electronics is a 555 based timer.

 

i doubt he would give the answer away here.

 

You could use multiple 555s to do it.

 

I was involved in digital ciruitry back in the 70s and early 80s, then moved away from it completely. I just imagined 555 timers would be passe, if not completely obsolete. You'll be telling me next you can still get a JK flip flop.

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The 555 can be set to have different duty ratio. Assuming fixed period (say > 1kHz) you could adjust the duty ratio to control the current through the LED.

You would need three 555's for RGB control! Not to mention all the peripheral components.

Off the top of my head I can't think of any modern application for a 555.

 

this implies a square wave which is not analogue.
what about syncronization? three independent oscillators will not stay tuned to each other unless some type of triggering circuit is employed.
i also don't see how this circuit would be simpler than a 3 stage counter.

ophiolite,
the 74107 is a dual J-K FF in a 14 pin package. this IC does not have a direct set.
the 7476 is a dual JK FF in a 16 pin package and includes the direct set function.
the 7473 is identical to the 74107 except the power is not on pins 7 and 14.
funny you should mention JK FFs because that is the only way i know of to achieve a truncated count.

 

By 'analogue', I mean using analogue components (555 is non-digital, internally) such as using rheostats or variable caps to control charge / discharge time.

The three 555's do not need to be synchronised, since the LED cores are independent.

 

call me dense but i cannot picture how you can achieve the specs in the OP with three unsynchronized oscillators.

 

Ah - I think we're talking about different functions. The OP has been edited, but in either case if using the 555's as PWMs then their synchronisation is unnecessary. If the colour to be produced is expected to change automatically (as per OP as it stands now) then other oscillators would need to be synchronised. If one doesn't care about the exact colour sequence, then three oscillators with different periods would accomplish a similar effect.

I guess it's all moot since digital control is so much easier!

 

yeah you could use a 555 and some DFF combinational logic, the 555 will clock the flipflops and cycle throught the sequence.. The outputs can be the various RGB terminals with whatever mix of voltage you need for hues... R1 on the 555 can be adjustable to change the frequency