Need Circuit Design -- Cheap...

You're trying to fix asymmetry, so I'd go with just a 1Meg pot, BUT, from the wiper insert a 1Meg resistor to the cap. Should give you enough adjustment room for now.

...Jim Thompson

--
| James E.Thompson, P.E.                           |    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

So it would look like this: Q1-Collector | | | |--| \ 0 - 1M 1M /555 (Trigger Pin) \ | |---/ | | / | \

--- /1 M Resister Q2-Collector \ | | + /---\ C1 1UF ----- 1uF | | GND

So now the total resistance between Q1 and Q2 Collectors will only be

1M Ohm instead of 2M Ohm. The added 1M Ohm will be on the wiper leading to U1 (555) Trigger, and C1 - 1uF Cap.

Is this correct?

Sorry to ask but I really never understood that part of the circuit other than the effect of dealing with the flashing, and will not ask you to explain it to me, it just struck me as more important that the total resistance between the transistors was the same.

I am glad I asked as I would have gone with my option 1 and put the 1M Ohm in series with the pot.

I plan to hit this early tomorrow, should not take long to breadboard it, I have everything laid out ready to wire together on the board.

Thanks

No, it should be...

Q1-Collector | | | |--| \ 0 - 1M 1M /555 (Trigger AND Threshold Pins!) | | + /---\ C1 1UF ----- 1uF | | GND

...Jim Thompson

--
| James E.Thompson, P.E.                           |    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

OK, I got it now, and thank you once again, the new drawing is:

I have moved the feed to the 555 (Trigger & Threshold) to after the 1M resister as shown above.

If this works should I still order a 2M resister and go back to the original design, or can I stick with this. Long term stability is important so if this compromises the design I will get the 2M Ohm opt ASAP and put it all back to how it was.

Thanks

On the assumption that the duty cycle is around 50%, I'd just use one of the 1M pots, with a 470K resistor at each end.

--
    W
  . | ,. w ,   "Some people are alive only because
   \|/  \|/     it is illegal to kill them."    Perna condita delenda est
---^----^---------------------------------------------------------------

Sure, and what was the current flowing through the big loop just before and just after the switching event?

And how quickly does it change with time (on and off), given that you can model it as a resistor in series with an inductor, and a coil voltage V?

Best regards, Spehro Pefhany

--
"it\'s the network..."                          "The Journey is the reward"
speff@interlog.com             Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog  Info for designers:  http://www.speff.com

Hi Jim, What can I say, there is good and then there is great, you clearly fall in to the latter! There are links to the breadboard pictures at the end.

For the tests to this point I had the relays hooked to LED's to see the action. Tomorrow I will wire the contacts to the Remote Contacts, if for any reason I need to change the time the relays stay on for what part or parts would I tweak? (From eye-balling it they look perfect, but just in case I thought I would ask)?

I put it all on the breadboard today and the good news in order:

1. No Smoke!
2. Test of Relay 2 On then Off -- Passed (Simulated Armed)
3. Test of Relay 1 On then Off -- Passed (Simulated DisArm)
4. Test of Relay 1 & 2, no change - Passed (Simulated Flashing)
5. Hooked to X-10 DS-7000 -- No Smoke, No Disruption of DS-7000
6. Test of Relay 2 On then Off -- Passed (Hooked to DS-7000 LED)
7. Test of Relay 1 On then Off -- Passed (Hooked to DS-7000 LED)
8. Test of Relay 1 & 2 no change -- Passed (DS-7000 LED Flashing)
9. Alarm Silanced, LED still flashing, no relay action -- Passed
10. Triggered alarm, LED Flashing, no relay action -- Passed
11. Disarmed System, LED Off -- Relay 2 One Then Off -- Passed

Jim -- Again, you have been great and soon you will see I will follow though on my committment.

Thanks!!

PS -- Couple of Interesting notes:

-- While the LED looked and even showed on the scope to have about a

50/50 cycle, something holds the voltage pretty steady, the pot only needed a fraction of a turn. 3.6VDC seemed to be just right for point TT1.

-- The entire circuit draws 8.6mA, 14mA when the Relay comes on but that is counting the LED lighting, so likely more like 10mA total.

Glad that it's all working AOK!

R4*C4 (my drawing) sets relay ON time, probably best to increase C4 if you need more time.

Enjoy!

...Jim Thompson

--
| James E.Thompson, P.E.                           |    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     |

"When the government fears the People, that is Liberty. 
 When the People fear the Government, that is Tyranny."
         - attributed to Thomas Jefferson by his contemporaries

"The Constitution is not an instrument for the government to 
restrain the people, it is an instrument for the people to 
restrain the government -- lest it come to dominate our lives and
interests."      - Patrick Henry

I could not wait, I wired to the remote and the time is perfect, works every time, in fact it works better then when I push the button myself, I guess better contact...

So C4 controls the timing for both relays, if I ever do need to mess with it at least I know where to tweak now.

Thanks

Hi Bob, Thanks for your feedback and input, I built it today and it worked perfectly, actually on the first try!! I posted the detailed in a message to Jim so I will not repeat them here. Again Thanks!!

What it looks like on the breadboard. Neatness is not one of my strong suits, but it got the job done.

PS -- I took care of the donation, I hope your email and address are correct because that is where the info is going. Also, my real name and address will be in the information as well as my real email, I am sure you wouldn't but I always ask that folks don't ever post that information in the Newsgroups or anywhere on the web.

Thanks!!

Use E-mail data from website... in usenet posts it is _not_correct_.

Street Address on website _is_ correct.

I never divulge anyone's personal data.

Except for NymNuts'.

When I verify his data, the whole world, AND his employer will know ;-)

Long term lurkers here will recall that I broke a nauseating poster from Virginia; though I have heartburn that NymNuts is his resurrection :-(

...Jim Thompson

--
| James E.Thompson, P.E.                           |    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     |

"When the government fears the People, that is Liberty. 
 When the People fear the Government, that is Tyranny."
         - attributed to Thomas Jefferson by his contemporaries

"The Constitution is not an instrument for the government to 
restrain the people, it is an instrument for the people to 
restrain the government -- lest it come to dominate our lives and
interests."      - Patrick Henry

Thank you for your kindness!

...Jim Thompson

--
| James E.Thompson, P.E.                           |    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     |
             
 Stormy on the East Coast today... due to Bush\'s failed policies.

Congratulations! ;^)

--
    W
  . | ,. w ,   "Some people are alive only because
   \|/  \|/     it is illegal to kill them."    Perna condita delenda est
---^----^---------------------------------------------------------------

You are more than welcome.

Now I was about to build it on a perf board and just wire it all together when I noticed a great number of PCB makers, all the ones I saw, like PCBExpress even give you free software to do it. I knew there had to be a catch and there was, you need to know how to specifiy all the things they need to know...

The software in and of itself did not look all that difficult, but as I was reading what you needed to specify, number of layers, for this I think 2 sided would be just fine to keep traces from having to cross and put in jumpers, but then it got hairy, how many mm thick for the traces, how big to make each hole, how big to make the pads, the traces, and the list just went on and on, do I want a solder mask, silk screening, etc...

So if I may ask four questions --

1. Does it take a long time for someone who has never done this before to figure all of that stuff out using their software? I understand why they would need to know hole sizes and things so parts fit, but I have no clue as to the dia of the various parts. If you had to pick a place who would you pick?
2. Are there places you can just send the schemeatic to and the part data sheets and they will do it all? If so can someone point me towards one.
3. Is there anyone here that already uses one of these places, has the software and would do it for me for a small fee, that is, do the work the place that makes the boards needs done?
4. Are there places that could take this and convert it to all smd part specs and do a very small board?

Of course my guess is there are places that do all of these things, but I am looking for one that will be inexpensive. I was looking at about 100 bucks tops, I see I can get that from PCBExpress and get two boards but I have to use their software first and send them the set of files and details they need, found another place that had a first timers deal for 24 bucks a board, 2 board min. so 50 there and they also had the software.

Thanks...

Bob,

Do a Google search for "pcb design tutorial" and read the PDF file that pops up as the first hit. It's quite good, and will answer many of your questions.

The first time you make a PCB it tends to take a long time (anywhere from a week to a month) regardless of whose software you're using.

Your life will be a lot easier and the board far less prone to error if you order your parts first. You can just download the data sheets for your parts to get their dimensions, but having them in hand and measuring them yourself is always a good idea.

I don't really have a strong opinion here, but I can say I once used ExpressPCB and had no problems (but I had made plenty of boards prior, too).

The trick would be finding one that's within your budget. Soliciting hobbyists/college students/etc. to do this is going to be a lot cheaper than getting a commercial firm to do it.

Ah, there you go. Do you have a link to your schematic? (Or can your post it on ABSE?) I'm sure you'd get plenty of offers. (You might also want to ask on the Yahoo! groups for, e.g., Pulsonix, Eagle, KiCAD, gEDA, PADS, ORCAD, Altium, etc. -- these are various schematic capture/PCB laout tools.)

Sure... lots of places if you're just looking to take an existing design where parts are available in smaller sizes. If you're trying to "shrink" the design but the exact parts aren't available in smaller sizes, then you're back to asking someone to do at least a bit of engineering work which can get costly fast.

Also keep in mind that PCBExpress (and every other place that gives you "free" layout software) initially has you "locked" into their file format, meaning you can't have another PCB shop build the first set of boards unless you pay them for the Gerber files, which are the "universal" file format for PCBs. The cost of getting Gerbers varies significantly from one PCB house to the next.

(Regular PCB layout software produce Gerber files directly. The reason the PCB houses can give you the software is precisely because they know your board has to be made by them, at leas the first time, if you don't pay them for the Gerbers.)

---Joel

I haven't done any PCB layout for around 30 years, so I can't help you. I know there's a number of guys lurking here who earn their living at it, so I'll leave it to them to point you in the right direction.

...Jim Thompson

--
| James E.Thompson, P.E.                           |    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     |
             
 Stormy on the East Coast today... due to Bush\'s failed policies.

Hi Joel, Thanks for the lick in the right direction, my replies are between your answers/questions.

Thanks -- Will do that right after this reply...

I sort of figured that, which is why I reached out to see if there was a better answer...

I have all of the parts and data sheets, in fact I have a 100% working version of it on a breadboard, I like to smoke test something fora good couple of weeks before I build it on a board, so it is cooking away as I type, still no smoke, nothing getting hot, and operation

100% relable so far.

Ok, thanks, they seemed as good as any to me, but what do I know...

That was sort of the point of this message, but perhaps it would be better to start a new message thread asking specifically for that job.

Yes, I have a schematic and pictures of it on the breadboard: Schematic Link:

Bradboard Pictures:

I will hunt Digi-Key, for each of the parts I ordered, they had a lot of package options, I will see if there is an SMD option for every part, I suspect there will be for all but prehaps a couple caps and the 2 relays, but that would by OK.

I wondered what the catch was, but I will likely only ever make two of these, the one I use and a spare, but that is a good thing to know.

Thanks for your feedback!

Hi Bob,

I came in rather late on the thread; thanks for filling in the details.

I took a look at your schematic, and I believe that pretty much everything other than the relays is available in a smaller package. And someone else has probably mentioned you can change the two 555's into a single 556 and get a small space advantage.

If you don't find any takers and decide not to make the board yourself, I might be able to layout a proper PCB for you late next week, but I can't say for certain yet. You would come up with a sketch of roughly what dimensions you'd want the board to have and the parts' positions (for those you care about). You also should decide if you want a proper connector somewhere to hook it to the security console or if you'd just going to solder wires directly from the console to the board.

---Joel