556 dual timer problem

On a sunny day (Fri, 04 Dec 2009 16:43:05 +0000) it happened Ian Bell wrote in :

Sure, use a PIC. LOL

I had thought of that originally but I would need to by a development board and learn to program it. A 556 design was quicker and cheaper. As I have made and built a PCB for my friend I am hoping a simple fix is available. If not, then I will PIC it.

Cheers

Ian

Do you PIC your nose with them too?

Tim

Switch the trig and threshold pins, and the polarity used to drive them. Or it may be as simple as changing which supply rail the trigger cap is referenced to.

Tim

-- Deep Friar: a very philosophical monk. Website:

On a sunny day (Fri, 4 Dec 2009 11:01:28 -0600) it happened "Tim Williams" wrote in :

You can use a Z80 if you want.

On a sunny day (Fri, 04 Dec 2009 17:00:45 +0000) it happened Ian Bell wrote in :

Well ,I am not a 555 man, maybe you can clamp the output that drives the transistors ? with a transitor or 2, drive the base from a RC from the +.

Just a guess without seeing your circuit, try slowing the Vcc rise until the trigger input has risen. Or hold trigger high untill Vcc is stable. Can you post your circuit? Mike

A solution would be to put an Resistor + capacitor from Vcc to GND , the capacitor on the lower half and the midpoint to the RESET pin(s) of the 556. That way there is a small time delay before the RESET line goes high.

Shaun

No "use a PIC" posts without a full schematic and code listing, as well as an offer to use your own $150 development system to program the thing for him.

Thanks, Rich

A 10 uF or so cap from the reset input (pin 4 or 10, whichever) to ground, with, say, a 47K resistor to +.

This is a very easy hack; try it and report back, OK?

Good Luck! Rich

On a sunny day (Fri, 04 Dec 2009 09:39:27 -0800) it happened Rich Grise wrote in :

Look, dude, I could have written 'micro'. You will have to face the fact that lots of analog stuff can be done much easier in a PIC or some other, possibly less easy to obtain, less easy to program, with a more complicated instruction set, less reliable, more power hungry OTHER micro.

As far as 'development system' in this case you show no clue again, I do not have a PIC 'development system', I use a noppp programmer (less then 3 $ in parts), and gpasm (free) on a Linux (free) PC, and my tools are a scope and DVM. And I can program anything I want. So, before you spit out 'me want diagram, me want code, me want your time, me want all for free', learn to program. The most I think anyone should do here is show some pseudo code. All the asm and other code I have published here is a *gift*, and up to you to equal that, if you can. And finally you do not make the rules.

Oh, don't take yourself so damn seriously. ;-)

Cheers! Rich

On a sunny day (Fri, 04 Dec 2009 12:10:32 -0800) it happened Rich Grise wrote in :

Oh, well, I was just trying to help ;-)

Yabbut, I don't think Zilog makes 300 mil DIPs. My nose isn't this big,

Tim

How about an AVR that runs direct off the battery ? no Vregs needed....

On a sunny day (Fri, 4 Dec 2009 21:21:37 -0000) it happened "TTman" wrote in :

AVR runs on 12V?

On a sunny day (Fri, 4 Dec 2009 15:03:34 -0600) it happened "Tim Williams" wrote in :

I get: Flash Player 9 or later required to view this video. Please visit Adobe to get the latest version of the Flash Player.

I think this is a bad site, as I do have flash, too many popups too. But google shows the pic... SORRY google shows the picture. hehe

I wonder - is there a version where I can write the program in, say, C or BASIC, and upload it to the chip with nothing more than a breadboard and serial port? (i.e., no $150.00 dev. kit?)

Thanks, Rich

Thanks Rich; a couple of people have now mentioned that mod - reset is tied directly to Vcc right now so holding it low until things have settled down seems like a good solution. I'll get the PCB back from my friend and try it out.

Cheers

Ian