Re: The Sorcerer's Progress
(Picks up Campbell's soup can and clanks on the metal. "Hey, mom of New Jersey! Hang up da phone soze he can write some stuff!)
- njc
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Re: The Sorcerer's Progress
Problem in part is in the indicator circuits I'm using to watch what's happening. I'm still thinking BJT current-operated, and I didn't move the voltage reference to the battery rail. I'll take care of that after more sleep and a trip to Home Depot ... and maybe some work on Erevain.
- janet reid
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Re: The Sorcerer's Progress
I have a few more ideas if it turns out to be more than a few layout changes and extra resistors ....
Idea #3 (I think)
A phone surveillance system as in a system that feeds back a live stream of the phone to your laptop and hence enables easy identification whether said phone is on hook or off hook
Idea #4 (if the above idea is indeed idea #3)
Baby monitors all over the house to pick up off hook dial tones
As you can all see, I've kept the best ones for last. Not really, but at least it's high tech and a good personal motivation for njc to make his idea work. And soon?!
Hope you can make that trip soon, fix the circuit, finish a chapter and have a nice beer also soon! Keeping an eye on this space ...
- njc
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Re: The Sorcerer's Progress
Well, making the changes in the output 'instrument' circuits brings it to a point where I understand its behavior just about completely. Now, the low-level hysteresis circuit isn't being activated. If I move that mosfet to the battery rail, it will activate properly, but I'll have to clamp the output, which will require an extra node and a low-level zener diodes. The diodes I would need are several days away by mail order. I can make the topology more efficient to save a node, but the zener I don't have.
I can fake one temporarily with a bjt and resistors. That will have to be jury-rigged because it takes another node--unless I can be godawful clever somehow.
- njc
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Re: The Sorcerer's Progress
The change in the network topology is the wye-delta (or tee-pi) transform. Contrary to the article, I'm going from wye to delta to save a circuit node. I should have done it long before (and a practiced circuit designer would have) but I can do it now, and then drop one of the resistors and save some current (like a practiced circuit designer would have). The power rail edge of the circuit board will get even hairier, but I'll have room for the zener. Before I order any, I want to fake a zener with a bjt and two resistors. I'll have to jury-rig the connection off the circuit board, and temporarily change a resistor, but with a little bit of luck I'll have both low and high transition hysteresis back.
And then I can order a dozen low-current 2.1V zeners, and go back to work on the pilot/pigeon flasher.
Amy, your Ch11 is next.
- janet reid
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Re: The Sorcerer's Progress
Had to google what you mean by "node" (yeap, I'm that clueless), but I'm with you again (sort of). Saw ohm's law while googling/wiki'ing nodes - brought back vague memories. Pleasant ones - way back in the day I think I got the right answer when I used ohm's law the first time ever. It was 2 ohms. In any case, if it's starting to look and feel like practiced circuit designer stuff, then it can't be all bad and it doesn't matter if one took the short cut or the scenic route, as long as you get there!
ps - So you still have work on the pigeon flasher/pilot too. Sure you don't want to reconsider any of our (amy and me) other ideas?
- janet reid
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Re: The Sorcerer's Progress
amy s wrote:
(Picks up Campbell's soup can and clanks on the metal. "Hey, mom of New Jersey! Hang up da phone soze he can write some stuff!)
* bleep-bleep bleep-bleep * <----------- busy signal hehehehe
- njc
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Re: The Sorcerer's Progress
janet reid wrote:
ps - So you still have work on the pigeon flasher/pilot too. Sure you don't want to reconsider any of our (amy and me) other ideas?
I'm rather proud of that extra mosfet in the flash driver. Even with the bright flash, once I get low-leakage caps in there the -average- current draw will be under 10 milliamps. Four C cells should be able to keep the flasher up over 900 hours. Maybe even past 1200.
And I've got a half-decent third-order low pass filter integrated with the voltage transient protection. Not theoretically elegant, but quite effective.
- janet reid
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Re: The Sorcerer's Progress
I'd say once you've straightened out the problem here and there, it'll be a pretty nifty gadget.
ps - I would get an honorary mention in the patent application, yes? 
- njc
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Re: The Sorcerer's Progress
I'm not prepared to do the extensive patent search. I have a much simpler gizmo that might be patentable. Too bad Ron Popeil died. That's the kind of marketing it would need.
- janet reid
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Re: The Sorcerer's Progress
njc wrote:
I'm not prepared to do the extensive patent search. I have a much simpler gizmo that might be patentable. Too bad Ron Popeil died. That's the kind of marketing it would need.
Especially with the way cellphones (I think that's what you guys call what we call mobile phones over in the States - I'm trying my newly acquired slang on you guys) have taken over the market ..... Apps apparently is the way to go!
- njc
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Re: The Sorcerer's Progress
Cellphones won't keep you Christmas tree fresh.
- janet reid
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I have a strong suspicion our first (few) Christmas tree(s) in the US is/are going to die, quickly, unless it comes with instructions ...... Now I panic. I don't panic easily ......
- njc
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I was working on the Erevain chapters and had a small problem to fix. I found a solution that turns me back toward a hard question that I had avoided, even in my thinking. Now I'm thinking.
I think I may be fighting off a bug. I've needed a lot of sleep for the past five days.
- amy s
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Re: The Sorcerer's Progress
Janet,
Fake tree. Put on LED Xmas lights and leave them on when the tree is packed away for the end of the year. (Do not buy a pre-lit tree since the bulbs wear out. LED is the way to go) Pull out tree next year and plug in. Lights are already on. Easier to decorate. If you want the scent of pine, get an evergreen candlle and burn it in the room.
This means more time for family, sanity, and fewer needles to vacuum up after the decorations are taken down. Cut trees just need some water put in the base. Plantable Xmas trees need to be watered. They also need a hold dug in the ground in the fall. Otherwise, you have to dig frozen dirt to plant it in January.
Like I said. Go for the fake tree.
- janet reid
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Re: The Sorcerer's Progress
* scribbles on note pad - fake tree, LEDs, evergreen candle, matches *
ps - you so think like me! but instead of more time for family, more time for eggnog 
- janet reid
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Re: The Sorcerer's Progress
njc wrote:
I was working on the Erevain chapters and had a small problem to fix. I found a solution that turns me back toward a hard question that I had avoided, even in my thinking. Now I'm thinking.
I think I may be fighting off a bug. I've needed a lot of sleep for the past five days.
I hate those questions! But the sooner you get them answered, the better, because usually it improves the end result! Good luck!
ps - best advice (and I think amy would agree with me here) for fighting off bugs: eat a handful of sand and then drink a bottle of whiskey, sit back and let the drunk bugs throw each other (dead) with massive rocks .... but I really hope it's nothing serious like being stuck in bed with a cold or something for days *crosses fingers *
168 2015-02-08 13:45:38 (edited by njc 2015-02-08 13:45:53)
- njc
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Re: The Sorcerer's Progress
Depending on the family, putting the tree up and decorating it can be a real family party. Taking it down is more of a chore, but with everyone together it's doable.
- amy s
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Re: The Sorcerer's Progress
You have really wicked bugs in Australia, don't you?
I like the idea of more time for liquor. In fact, after the last night shift, I get a beer.
Oh, latest thought about the move. Don't forget to stockpile Aussie foods when you come over. Vegemite is pretty rare around here. Also, I know there is a big wine community in the country. That would make gifts for Xmas and thank you that no one in the US would turn down.
- njc
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Re: The Sorcerer's Progress
Sigh. Another thing I overlooked in my circuit change. I can try to shoehorn another resistor in, but instead I'm looking at yet another topology change, which might sharpen the low-level ON transition. It means trying a source follower configuration as a current source and taking the output from the mosfet drain. I've never used that before, so I expect I'll have to play with it a bit. OTOH it will get some troublesome things out of the way and reduce the congestion at the edge of the board where the power rails are.
- njc
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Re: The Sorcerer's Progress
amy s wrote:
You have really wicked bugs in Australia, don't you?
I've heard the bugs aren't bad so long as you don't try to order a drink in their bars.
- janet reid
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Re: The Sorcerer's Progress
njc wrote:
amy s wrote:You have really wicked bugs in Australia, don't you?
I've heard the bugs aren't bad so long as you don't try to order a drink in their bars.
True! Our bugs sober are push-overs!
- janet reid
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Re: The Sorcerer's Progress
njc wrote:
Sigh. Another thing I overlooked in my circuit change. I can try to shoehorn another resistor in, but instead I'm looking at yet another topology change, which might sharpen the low-level ON transition. It means trying a source follower configuration as a current source and taking the output from the mosfet drain. I've never used that before, so I expect I'll have to play with it a bit. OTOH it will get some troublesome things out of the way and reduce the congestion at the edge of the board where the power rails are.
Looks like it's idea time again ....
Idea #(x+1)
where x = the number of my last idea
A big, strong magnet to keep the headset and the phone body connected. You can even be fancy and use an electromagnet instead of a boring, normal one .... 
But in any case, I think it's time for a photo or two again? Or is it way too soon so be asking?
- janet reid
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Re: The Sorcerer's Progress
amy s wrote:
Oh, latest thought about the move. Don't forget to stockpile Aussie foods when you come over. Vegemite is pretty rare around here. Also, I know there is a big wine community in the country. That would make gifts for Xmas and thank you that no one in the US would turn down.
I think I need a bigger suitcase ..... Will see what I can do! Don't need xmas gifts so much this time of year, but I have a lot of thank you's to get around to ... Aussie goodies vs thank you gifts. Life's all about hard decisions, heh?
ps - How do you know about Vegemite?! *listens to white noise while trying to radio the Australian Federal Police*
- njc
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Re: The Sorcerer's Progress
janet reid wrote:
But in any case, I think it's time for a photo or two again? Or is it way too soon so be asking?
I have a passable photo of the circuit drawing. (The Pitman outline for "Shogran's" is visible just above it!) As soon as I get home and get my photobucket password I'll put it up.
