Re: Need Circuit Design -- Cheap...

Thanks -- Good catch -- I updated the drawing.

Also changed the CD to SN parts. Also in another post asked you what
the difference was between all of the various letters in addtion to
the part number meant, I did no mean for you to explain every
variation, but if you could suggest a specific part number. Please not
that just a "74HCxxxx" does not seem to exist at Digi-Key, they all
start with like "SN74HCxxxx" or "MM74HCxxxx" or "CD74HCxxxxx", the
best I could make out is it was brand differences.

Same URL: (Relay powered now)
http://people.delphiforums.com/wildbill47/X10/New_Alm_Ctr.jpg

Thanks


On Sun, 26 Apr 2009 17:35:01 -0700, Jim Thompson
<To-Email-Use-The-Envelope-Icon@xxxxxxxxxxxxxxx> wrote:

On Sun, 26 Apr 2009 19:49:14 -0400, Bob Thomas <bobtms@xxxxxxxxxxxx>
wrote:

Hi Jim,
OK, I think we are there, I have redrawn your schematic to the
actual parts and like before I think I have all of the right parts and
connections, if you could do a quick compare I would appreciate that
to ensure I interpreted your drawning correctly.

http://people.delphiforums.com/wildbill47/X10/New_Alm_Ctr.jpg

Tomorrow. Dinner time.

Quick glance... lower relay, how does it get +5V for the coil?


With the new parts I am just going to stick with what you specified,
so that other questions are off the table.

This leaves me with one question, you have the Input Signal from the
LED going through 2 inverters, U2A & U2B, just out of interest sake I
was wondering why, if you inverst something twice don't you just end
up with the same thing you started with?

With no load specs for you controller, I was reluctant to load it down
with a resistive (read: current) load.


Thanks!!

PS Upon your reply I will put in the order. I am glad you took the
iterations to refine this so I did not have a bunch of orders to
Digi-Key.


On Sun, 26 Apr 2009 12:29:44 -0700, Jim Thompson
<To-Email-Use-The-Envelope-Icon@xxxxxxxxxxxxxxx> wrote:

On Sun, 26 Apr 2009 15:14:01 -0400, Bob Thomas <bobtms@xxxxxxxxxxxx>
wrote:


OK, So I will draw up the second design and get the parts for it first
and give it a go.

Will post drawing of actual parts / pin outs, this is more of just a
sanity check for me to ensure I and interpreting your drawing
correctly.

Alas, the wife is "making" me go help our new neighbor now, won't be
back to this for a few hours. I get to move furniture around and
re-wire his phone connedtions, the prior owner had 4 lines! One for
each kid, and when the telco hooked him up they did not connect the
internal lines all to the new live line so he only has a few jacks
working, that should be easy enough, it is the furniture I am not
looking forward to...

What? A _guy_ who can't move his own furniture around ?:-)

I only help people who really need it... new _babes_ in the
neighborhood ;-)


Again,
Thanks -- Will post new diagram soon.

On Sun, 26 Apr 2009 11:44:02 -0700, Jim Thompson
<To-Email-Use-The-Envelope-Icon@xxxxxxxxxxxxxxx> wrote:

On Sun, 26 Apr 2009 14:39:46 -0400, Bob Thomas <bobtms@xxxxxxxxxxxx>
wrote:


Hi Jim,
Again thanks! This looks like it is a little more simple, one
thing I did notice was that on page 2 of the PDF that in this design
Relay 2 triggers during the alarm triggered phase, where in the
original one it triggered after the system was disarmed for a short
time which was perfect. Is this just a mistake on the PDF or did the
changes in the circuit cause Relay 2 to fire too soon?

I applied a 66/33 duty-cycle, so the original circuit fails, as I
predicted. The third page shows the new circuit behavior with 66/33
applied, but the pot adjusted for average value at "TT1" as VCC/2.


Thanks,
Bill

PS -- I will draw up a new "as-built" schematic of the second design
once you let me know about the chanfge in Relay 2 and hold off on the
parts order.

Also in the original jpg I gave a link to the 555c was mislabeled
LM7555C, I have corrected that to LM555C and reposted the schemtatic.
(same address, just corrected picture.

http://people.delphiforums.com/wildbill47/X10/New_Alm_Ctrl.jpg

On Sun, 26 Apr 2009 10:45:35 -0700, Jim Thompson
<To-Email-Use-The-Envelope-Icon@xxxxxxxxxxxxxxx> wrote:

On Sun, 26 Apr 2009 01:57:53 -0400, Bob Thomas <bobtms@xxxxxxxxxxxx>
wrote:

[snip]

You may not need this, if your blinking duty-cycle is 50%/50%, but if
it's not, then one possible way to cope...

www.analog-innovations.com/SED/AlarmController-DutyCycleFix.pdf

(I also changed the logic to reduce package count.)

...Jim Thompson

...Jim Thompson

...Jim Thompson

...Jim Thompson

.

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