Anybody want to bid a circuit design?

Oh cool -- that looks like a nice step beyond batchpcb (batchpcb is really aimed at onesie-twosie stuff).

I've been playing with what one might do with this, and think my estimate of $15.00 for the BOM (even before I knew of pcbcart.com) was a bit excessive. But then, that depends on whether things like relays and circuit protection devices and all of that are really required, or if they can be left out.

--
My liberal friends think I'm a conservative kook. 
My conservative friends think I'm a liberal kook. 
Why am I not happy that they have found common ground? 

Tim Wescott, Communications, Control, Circuits & Software 
http://www.wescottdesign.com

a couple of 555s and a few resistors and capacitors, under $1 in parts excluding pot and board (matchbox sized, or smaller)

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Two. one to generate pulses and the other to wait when N pulses go out port 'A' and to drive port 'B', and shut doen the pulse generator.

The pot controls either the pulse rate of the first or the delay time of the second,

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Yep, And maybe a little jelly-bean glue-logic for the sequencing. ...Jim Thompson

--
| James E.Thompson, CTO                            |    mens     | 
| Analog Innovations, Inc.                         |     et      | 
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    | 
| Phoenix, Arizona  85048    Skype: Contacts Only  |             | 
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  | 
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I love to cook with wine.     Sometimes I even put it in the food.

generator.

By the time you do that, you will have already far surpassed the simplicity, elegance, and cost of a $0.50 microcontroller. The only possible advantage of a 555 is its output drive capability. Of course if all you know is how to swing an antique hammer, one might never even consider the advantages of a screwgun.

Paul

Dumbass. If the OP had the tools and knew how to program a 50 cent processor, he wouldn't be asking for help on news:sci.electronics.basics

news:sci.electronics.basics

Before you start spouting off, you should pay more attention. The OP has

already used an Arduino and declared it to be too expensive with more features than needed. The tools for the PIC10F322 consist of a $45 PICkit3 and the $12 demo board. I was referring to Jim Thompson's love of the ancient 555 which he likes to squeeze into any design, rather than go with more modern (and better) technology.

So, right back atcha!

Paul

When has Jim posted a design with a 555? It's John Fields who suggests designs using them, to people without the skills to design and program something from scratch. Unless the OP plans on doing a lot of design with PICs, it's a waste of time to learn to program them for such a small projected run of boards. Your attitude stinks. Modern isn't always better. In some cases, it isn't worth a damn.

before you spout off. Using the Arduino has nothing to do with programming a 50 cent PIC processor. I have a couple mega 2560 Ardunio, and it's nothing like building a controller from scratch & writing the code. The Arduino uses what they refer to as 'Sketches' or .pde files. From what I see online most users can't even port a sketch from on board to another let alone write one from scratch. I bought the Mega boards to see if they would be useful, but decided to use some Atmel chips on custom boards instead.

I'll admit that most of my machine language work was with 6502/6510 and 6803 processors.

The code for the 6502/6510 was written byte at a time, without a compiler. The code for the 6803 was a simple compiled program that took

9600,8,N,1 serial to control a group of six PIO chips in a programmable test fixture where a Qbasic program let you specify the port, direction & either load the data or read the results. It took a manual test from 12 man hours to 30 seconds, and gave the tech pointers on what to look for at each known failure. It was the inteface board between the front panel & all the modules in a $20,000 telemetry receiver. It took longer to plug in all the cables than to run the actual tests.

and

such

Jim suggested a 555 or this. But it needs at least two of them or a 556,

plus "glue" logic and various other components for timing. If the customers decide that a different sequence is desired, they're SOL unless they buy new ones or change components or add cuts and jumpers. The OP has asked for help, and apparently has some experience with programming. Or I could do it for him.

took

inteface

actual

I could say "yawn", but I have no desire to belittle your accomplishments. However, I have had extensive experience with programming of microprocessors such as the 8085 and Z80. At that time, around 1985, it was pretty much all assembly code. These projects involved thousands of lines of code, and used two or more 2764 EPROMs. Starting around 2002 I started using Microchip PICs for various projects, and I attended two of their MASTERs conferences in

Arizona. I have designed simple circuits as well as more complex projects using serial communications and USB.

The OP's application seems to be a very simple project that would take no more than about a day to design, and a few hours more to do the PC boards. I usually work with small production runs such as this, so I'm confident that I can help him. It's probably not a source of much money, but then again

it's only a few days of part time work.

Paul

No, it doesn't. The 555 would be the adjustable clock. A couple Exclusive OR gates, a flip-flop and a settable counter IC could provide the two outputs as desired, and at the same clock rate. The counter would not only drive the output through the EXOR gates, but toggle the flipflop. Yes, it can be softeware and a processor, but people will never learn how simplew things work without some hands on design with the basic components. It's like people who jump in with both hfeet with Spice, then can't understtand why their perfect design does nothing but smoke. Have you done everyting in software for so long that you can't see a simple design in your head? 30 years ago, i needed an electronic lock. I used a single 4017 for a five digit lock. You had to select the right digit at each step or it rested the counter & timed out for 15 secoonds. A low power switching transistor drove a low power relay, end everything fit on the back of the 16 button non-matrix surplus keypad. Total cost was about 70 cents, anbd the whole project took onder 30 minutes.

Simple designs should stay that way.

Then do it, don't just say that you can.

Go ahead and yawn your head off, I don't really care. Programing wasn't part of my job. I did it because the one who was assigned the the task didn't do it on time. I also wrote a decomplier for the 6502 for my own use on the old Commodore computers and disk drives.

Assembly isn't machine code. You let the assembler crunch your code to spit out machine code. Don't confuse people who have never written any code.

I did some work with both the 8085 and Z80, but not enough to ever like them. I really didn't like their support chips.

555s were $0.13 by the 100 last time I looked.

power supply range may help too, but if he wants 5V he can probably provide a 5V supply.

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you've got a 5 bit counter that responds to a potentiometer for its limit?

seriously it's much easier to just use 2 555s and a few passive components.

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He could use a demo/trial version of PICBASIC Pro or similar - it is well within his budget and the 30 or 40 line code limitation is not going to be an issue. Makes a PIC very easy to program.

wrote in message news: snipped-for-privacy@4ax.com...

Hello Eric

Have a look at this simple pulser made from 2 NE555 ICs (LTSpice schematic).

There are two 555 ICs, just because LTSpice has a model for it. In a real device, you'll likely want to use a 556 IC (dual 555 in a package) instead.

The values of some passive components may need a little "polishing" too.

It's not completely finished for use in a product (may need an inverter at the output, depending on the polarity you need, or a driver). If it needs industrial robustness (EMC-wise, withstand ESD or even surge at the outputs), that would mean transient suppressors and even more passive components.

Also a reverse polarity protection diode could be a good idea if the power is provided by a plug-in power supply or a battery, giving the user a chance to carelessly mess up the polarity.

Regards Dimitrij

--- cut here for the LTSpice file ---

Version 4 SHEET 1 2384 680 WIRE -624 -512 -720 -512 WIRE -288 -512 -624 -512 WIRE 208 -512 -288 -512 WIRE 336 -512 208 -512 WIRE 720 -512 336 -512 WIRE 864 -512 720 -512 WIRE 1184 -512 864 -512 WIRE -288 -448 -288 -512 WIRE 720 -432 720 -512 WIRE 336 -400 336 -512 WIRE -192 -320 -448 -320 WIRE 208 -320 208 -512 WIRE 208 -320 32 -320 WIRE 1248 -304 592 -304 WIRE -192 -256 -240 -256 WIRE 336 -256 336 -320 WIRE 336 -256 32 -256 WIRE 720 -256 720 -352 WIRE 816 -256 720 -256 WIRE -192 -192 -352 -192 WIRE 160 -192 32 -192 WIRE 928 -192 720 -192 WIRE 1184 -192 1184 -512 WIRE 1184 -192 1152 -192 WIRE 336 -176 336 -256 WIRE -720 -144 -720 -512 WIRE -288 -128 -288 -368 WIRE -192 -128 -288 -128 WIRE 80 -128 32 -128 WIRE 816 -128 816 -256 WIRE 928 -128 816 -128 WIRE 1248 -128 1248 -304 WIRE 1248 -128 1152 -128 WIRE -624 -64 -624 -512 WIRE 928 -64 896 -64 WIRE 1248 -64 1152 -64 WIRE -240 -48 -240 -256 WIRE 160 -48 160 -192 WIRE 160 -48 -240 -48 WIRE 336 -48 336 -96 WIRE 336 -48 160 -48 WIRE -288 0 -288 -128 WIRE 592 0 592 -304 WIRE 592 0 -288 0 WIRE 864 0 864 -512 WIRE 928 0 864 0 WIRE 1344 0 1152 0 WIRE 1360 0 1344 0 WIRE 1520 0 1440 0 WIRE 1728 0 1600 0 WIRE 1248 112 1248 -64 WIRE 1248 112 592 112 WIRE -288 144 -288 0 WIRE 160 160 160 -48 WIRE 896 192 896 -64 WIRE 1504 192 896 192 WIRE 464 240 416 240 WIRE 592 240 592 112 WIRE 592 240 528 240 WIRE 80 256 80 -128 WIRE 592 272 592 240 WIRE 816 288 816 -128 WIRE 1344 336 1344 0 WIRE -352 384 -352 -192 WIRE 224 384 -352 384 WIRE 416 384 416 240 WIRE 416 384 368 384 WIRE 464 384 416 384 WIRE 592 384 592 336 WIRE 592 384 528 384 WIRE -720 464 -720 -64 WIRE -624 464 -624 0 WIRE -624 464 -720 464 WIRE -448 464 -448 -320 WIRE -448 464 -624 464 WIRE -288 464 -288 208 WIRE -288 464 -448 464 WIRE 80 464 80 320 WIRE 80 464 -288 464 WIRE 160 464 160 224 WIRE 160 464 80 464 WIRE 592 464 592 384 WIRE 592 464 160 464 WIRE 720 464 720 -192 WIRE 720 464 592 464 WIRE 816 464 816 352 WIRE 816 464 720 464 WIRE 1344 464 1344 400 WIRE 1344 464 816 464 WIRE 1728 464 1728 0 WIRE 1728 464 1344 464 WIRE -720 560 -720 464 WIRE -352 560 -352 384 WIRE 1504 560 -352 560 FLAG -720 560 0 FLAG 1504 192 OUTB FLAG 1504 560 OUTA SYMBOL Misc\\NE555 -80 -224 R0 SYMATTR InstName U1 SYMBOL Misc\\NE555 1040 -96 R0 SYMATTR InstName U2 SYMBOL voltage -720 -160 R0 WINDOW 123 0 0 Left 2 WINDOW 39 24 44 Left 2 SYMATTR InstName V1 SYMATTR Value 5 SYMATTR SpiceLine Rser=100m SYMBOL cap -640 -64 R0 SYMATTR InstName C1 SYMATTR Value 1µ SYMATTR SpiceLine Rser=10m SYMBOL cap 288 368 R90 WINDOW 0 0 32 VBottom 2 WINDOW 3 32 32 VTop 2 SYMATTR InstName C2 SYMATTR Value 22n SYMATTR SpiceLine Rser=10m SYMBOL res 384 368 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R1 SYMATTR Value 100 SYMBOL schottky 528 368 R90 WINDOW 0 0 32 VBottom 2 WINDOW 3 32 32 VTop 2 SYMATTR InstName D1 SYMATTR Value BAT54 SYMATTR Description Diode SYMATTR Type diode SYMBOL schottky 464 256 R270 WINDOW 0 32 32 VTop 2 WINDOW 3 0 32 VBottom 2 SYMATTR InstName D2 SYMATTR Value BAT54 SYMATTR Description Diode SYMATTR Type diode SYMBOL cap 576 272 R0 SYMATTR InstName C3 SYMATTR Value 470n SYMATTR SpiceLine Rser=10m SYMBOL cap 800 288 R0 SYMATTR InstName C4 SYMATTR Value 100n SYMATTR SpiceLine Rser=10m SYMBOL res 704 -448 R0 SYMATTR InstName R2 SYMATTR Value 4k7 SYMBOL res 1456 -16 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R3 SYMATTR Value 470 SYMBOL res 1616 -16 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R4 SYMATTR Value 47k SYMBOL cap 1328 336 R0 SYMATTR InstName C5 SYMATTR Value 10n SYMATTR SpiceLine Rser=10m SYMBOL cap 144 160 R0 SYMATTR InstName C6 SYMATTR Value 2µ2 SYMATTR SpiceLine Rser=10m SYMBOL res 320 -192 R0 SYMATTR InstName R5 SYMATTR Value 47k SYMBOL res 320 -416 R0 SYMATTR InstName R6 SYMATTR Value 2k2 SYMBOL cap 64 256 R0 SYMATTR InstName C7 SYMATTR Value 10n SYMATTR SpiceLine Rser=10m SYMBOL res -304 -464 R0 SYMATTR InstName R7 SYMATTR Value 4k7 SYMBOL cap -304 144 R0 SYMATTR InstName C8 SYMATTR Value 100n SYMATTR SpiceLine Rser=10m TEXT -754 622 Left 2 !.tran 10 startup uic TEXT 1352 -104 Left 3 ;R4 is an approx 50K potentiometer (audio taper),\nit controls the number of pulses generated. TEXT 1352 -472 Left 3 ;Put switch in series with the power source TEXT 1352 -352 Left 3 ;Use NC7SC125 or similar line drivers\nto drive the outputs, invert if needed. TEXT 1352 -232 Left 3 ;Adjust pulse frequency with C6 and R5.\nUse a pot plus 4k7 for R5 if needed.

[snip]

I only bring up the 555 because it annoys the elitist crowd so much

That elitist crowd can't really "design" anything. All they can barely do is follow the instructions on programming some microprocessor, if it's pretty much all pre-canned.

But the 555 is actually quite an elegant design (Hans Camenzind, R.I.P.)

So elegant in fact, that it's trivial to design an equivalent in modern CMOS that will do 500MHz. ...Jim Thompson

--
| James E.Thompson, CTO                            |    mens     | 
| Analog Innovations, Inc.                         |     et      | 
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    | 
| Phoenix, Arizona  85048    Skype: Contacts Only  |             | 
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  | 
| E-mail Icon at http://www.analog-innovations.com |    1962     | 
              
I love to cook with wine.     Sometimes I even put it in the food.

Not to mention Pfeet, or LTfeet ;-)

-- "For a successful technology, reality must take precedence over public relations, for nature cannot be fooled." (Richard Feynman)

provide

Actually it's just more challenging to design a circuit using 555s and logic components, and sort of a "badge of honor" to be able to do so, even if the end result is inferior or no better than what could be done with a PIC. It's like someone wanting to build a cabin using nothing but hand tools, like Abe Lincoln. It may be a "noble" project and a learning (and muscle-building) experience, but if your goal is to get the job done, there's nothing like a chain saw.

Paul

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Go to "Gated logic pulser" at alt.binaries.schematics.electronic, or 
click this: 

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