high voltage from old telephone to BSII
snapperjonno
Posts: 6
Hello all,
I live in New Zealand, and have bought some old bakelite telephones here
that have crank handles, which when turned use a magneto generator to
generate approx 0 to 120 volts of AC power (depending on how fast you
turn the handle).
I want to connect the telephones to send a variable signal to my laptop
running Max/MSP that will control audio sources - the faster you turn,
the more power is generated and the higher the value sent as a signal.
I have a BSII microcontroller and wonder if it is possible to convert
this relatively high variable voltage AC power through the BSII to a
variable digital signal, and if so how?
If this is not possible through the the Basic Stamp, can·anyone suggest any
other approches to getting the signal through?
Thanks in advance for any suggestions,
Jonno
I live in New Zealand, and have bought some old bakelite telephones here
that have crank handles, which when turned use a magneto generator to
generate approx 0 to 120 volts of AC power (depending on how fast you
turn the handle).
I want to connect the telephones to send a variable signal to my laptop
running Max/MSP that will control audio sources - the faster you turn,
the more power is generated and the higher the value sent as a signal.
I have a BSII microcontroller and wonder if it is possible to convert
this relatively high variable voltage AC power through the BSII to a
variable digital signal, and if so how?
If this is not possible through the the Basic Stamp, can·anyone suggest any
other approches to getting the signal through?
Thanks in advance for any suggestions,
Jonno
Comments
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
·1+1=10
This all sounds a bit tricky and complicated - sorry, I'm not experienced in electronics! I understand the step-down transformer (but have no idea about how to source one or how big they are or cost!) but am lost on how to full wave rectify the signal or place large electrolytic capacitors on the output. Also, what type of ADC would I need?
Approaching this from a different angle, can you think of any other component I could substitiute the generator in the phone for, that on turning a handle you could get a signal into the PC that varies according to how fast it is turned?
Thanks again
Since you have what might be called a "high voltage, telephone related problem", let's address it just that way, and at that level (but not for long). Under the pushbutton caps of multi-line desk telephones are small incandescent lamps which cause the individual line buttons to glow when the line is active, and cause it to blink when a call is on hold. At least that's true of lighted US multi-line phones.
The particular incandescent lamps used in most telephone applications share three common features: the unusual base, the particular physical size, and a flattened top. The unusual base is called a "telephone slide base", the particular size is known as T-2 (explained below), and the flattened top is to allow as much light as possible to escape through the end (top) of the bulb. Here is a picture of a typical incandescent lamp for telephone applications:
http://www.atlast.com/catalog/i96.html
I'm going to presume you have 110 volt mains there in NZ, but even if it's 220 volts, most everything I say below will hold true. You just may have to source the 110 volt telephone slide base lamps via the Internet, rather than locally.
As you may note, they come in 120 volts (as well as other, lower voltages). The size designation T-2 may now make some sense, since you've now seen it. The "T" indicates that it is a tubular shape, and the "2" is the number of 1/8ths of an inch across the bulb diameter; thus this is 2/8ths or 1/4" in diameter. This "shape designation" + "diameter in 1/8ths" designation is common to all large lamps. Large lamps are also defined as high voltage (mains voltage) lamps.
Connect this telephone bulb to the two lines coming from your ring generator, and solder them to the metal shell base. Now grab a photo-resistor, or photo-transistor, of an appropriate type, and attach insulated wire leads to it, also by soldering them. Now, place the thin lamp in one end of a heat resistant, opaque 1/4" tube, and the photo-sensitive device in the other so they face each other inside the tube. You may need to use some tape on the photo-device end to optically seal the tube.
Now, as the lamp gets brighter (increased voltage), either the resistance will change at the far end (photo-resistor), or a smaller/larger voltage will be produced (photo-transistor), depending on the type of photo-sensitive element you have chosen to install at the other end of the "drinking straw". We have just transistioned, safely, from a variable high voltage signal, to a correspondingly variable (1 to 1 ratio) low voltage signal!
The rest should be fairly straightforward.
Regards,
Bruce Bates
Thank you so much for your response. I regret to say that the telephones I have are a very much more antiquated model than the type you have discussed, having nothing as sophisticated as a light on board! Please see the attached image (I found here)·of a similar -·but not exact - design.
To my knowledge the generator is not a ring generator, but one that works similarly to a dynamo, generating AC power, up to 100+volts that was used to send a signal to a swithboard which was answered by an operator who would connect the call.
The phone has no buttons, or even a dial, for making calls or dialling numbers itself. It pre-dates this technology!
I understand what you are driving at though. Perhaps there is some way of connecting a lightbulb to the generator to do what you suggest which gets detected by a photo resistor...
BTW, NZ has 240 volts power, not 110 as in the US, but I guess that's no longer relavent to this!!!
Perhaps with this added information you have conjoured up another great solution?!?
Thanks again and the very best wishes,
Jonno
I suppose you can call it a dynamo, worm shocker, party shocker, or a generator, as you see fit. The telephone companies around the world have always referred to it as a "ring generator" because it generates a high voltage signal which passes over the phone lines to RING the BELL at the far end. Ergo - it generates a ring, thus it's a ring generator. Blame the nomenclature on the telephone companies
Everything I said still stands. What, if any, telephone, you may or may not have, is wholly insignificant to my methods. In fact, I PRESUMED you had no local phone at all, just the dynamo box on the back of the picture you provided. That's all I had, when I was a kid!
According to the post to which I responded, you said:
"I want to connect the telephones to send a variable signal to my laptop
running Max/MSP that will control audio sources - the faster you turn,
the more power is generated and the higher the value sent as a signal."
It was my impression, based on what you said above, that you wanted the variable AC ring generator voltage output to be available in some usable form, as a low voltage input, to some other device. I presumed that you would be using a Stamp, to read that (now) low voltage input (through an analog to digital converter), and send the acquired voltage as data to your laptop.
It appeared as though you didn't like the transformer solution offered by others, so I thought I'd offer a suitable optical solution, that was safe, and reasonably easy to construct, from readily available parts. I'm not sure where to go from here, if that's not what you wanted.
To utilize my method, you would need to source the lamp, the photo-device, and a 1/4" piece of tubing. I made no presumption that you had any of that on hand, or as a part of your existing telephone. Sorry if that wasn't clear.
Regards,
Bruce Bates
Someone correct me if I'm off (or when..
So, at 120Vac and 60Hz we get a representative reading....but if you're turning this handcrank, isn't the frequency different (related to how fast you're cranking?)
Would a meter indicate this properly?
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
·
Steve
"Inside each and every one of us is our one, true authentic swing. Something we was born with. Something that's ours and ours alone. Something that can't be learned... something that's got to be remembered."
Connect the 240VAC side of any litte unregulated power supply brick to the ring generator.
Measure the voltage on the LVDC side when turning the crank.
This should give an idea to start from.
Regards
Here is a page showing the circuit I am describing: http://hyperphysics.phy-astr.gsu.edu/hbase/electronic/rectbr.html
Its the second one titled "Bridge Rectifier, RC Filter".
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
·1+1=10
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Think outside the BOX!
I'd connect·the phone high-voltage to a lamp, and couple the lamp to a photocell, and the photocell to a voltage to frequency converter, and the V-to-F to the STAMP.· The phone would be isolated from the STAMP, and the final input to the STAMP would be a function of the cranking action on the phone in a form that the STAMP could use.
Sorry, but I don't figure there is a non-electronic (i.e. Production 'Manager') means of doing this.
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
When you get 1st Place in the "Darwin Awards", you're a Winner & a Loser.
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Think outside the BOX!
100 pf 20kohm AC+ -----------||---------o-----/\/\------ p0 Stamp | | --- small zener diode 5v ^ | AC- ------------------------o------------- VssAlternatively a pickup loop, by having the generator drive a load, a resistor or a lamp. Then put a loop of wire with enough turns in proximity.
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Tracy Allen
www.emesystems.com
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
·1+1=10
Of course, you could go back to the transformer that was first mentioned.
What you want is a simple '6 Volt doorbell transformer' which is easily available at building supply or electrical supply houses. Everyone has a doorbell, right?
Or, you might just use an AC·'wall wart' to do the same thing.
I suppose you can look to Jaycar in Australia for parts.
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
"When all think alike, no one is thinking very much.' - Walter Lippmann (1889-1974)
······································································ Warm regards,····· G. Herzog [noparse][[/noparse]·黃鶴 ]·in Taiwan
Post Edited (Kramer) : 12/6/2005 5:19:58 PM GMT
Though considering Jonno's inexeperience I still think he should use a prepackaged unregulated power supply and ADC. http://www.cybermarket.co.uk/ishop/923/shopscr1611.html·is a good example.
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
·1+1=10
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
·1+1=10
The output he wants
Can be generated using PWM on another pin after reading the input pulses.
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Think outside the BOX!
Maybe additional isolation would be a good idea, to forstall a shocking experience. And a small capacitor at the Stamp input to reduce hash noise.
more isolation... 100 pf 20kohm AC+ -----------||---------o-----/\/\------o-- p0 Stamp | | | | small zener diode 5v --- _|_ ^ --- 0.001uf | 1kohm | AC- -------------||----------o----/\/\-------o--- Vss 100 pf▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Tracy Allen
www.emesystems.com
At this is a sound art project, the idea of having a visual element (ie the light getting brighter as well as the soundscape changing) is actually very appealing. I realise the suggested design requires the lamp and photo-resistor to be coupled together and hidden, but perhaps I can figure a way of installing it out in the open... or using 2 bulbs, one to look at and another to send the messages...
This was also suggested:
Sorry to be thick, but what function does the F-to-V perform, and is it necessary?
Thanks again, Jonno
So far as a V-to-F, you wouldn't have to use anything terribly fancy -- you could use the VCO (voltage-controlled oscillator) from a 4046.
You could apply the voltage from the photocell to an analog-to-digital (A-to-D) converter and get a digital signal for the STAMP that way, too.·
I think we're all brain-storming.
Maybe you could measure the high-voltage output, do some experimenting, and·report the results (e.g.:·slow speed = X volts, med speed = Y volts, fast speed = Z volts.)· Maybe you can find some low-wattage light bulbs and see if you can actually get a rise from them.
I don't know what the STAMP's utility is in this project.· What's your plan?· With your last post we know a bit more.
Post Edited (PJ Allen) : 12/7/2005 1:14:09 AM GMT
In the UK I have converted old dial phones to interact with my laptop before - by connecting the microphone and earpiece to the soundcard, and the hang-up switch to the chip from an old computer keyboard so that when the receiver is lifted it sends a signal that the number '9' has been pressed in turn triggering a change in the software patch running on the laptop to run the next sequence in sound processing/sample playing. The result is an interactive experience on an old telephone where your voice gets recorded in chunks and slowly processed/chopped about etc and played back at you through the phone over time, building to a cacophony of madness. A bit of fun, but quite effective! The project actually involved 2 phones working together so conversations could be held between them until the whole experience became overwhelming for the participants, when they hung up - only to switch the audio over to an amp/ speaker wired into the body of the phones themselves just to freak them out a bit more..! then the sequence reset itself until the next unsuspecting person came along...
Anyway, I digress! Now I've just emigrated to New Zealand leaving the phones behind, having not fulfilled my inner need to create more whacky uses for these wonderful and evocative machines amongst other ideas simmering away mixing antiquated hardware with digital technology to create sonic artworks.
Just before I left I bought a Basic Stamp, having found out that they are great for interfacing the 'real world' with computers - perfect! I haven't had the time to even get the thing out the box beyond making an LED get brighter and darker over a particular timeframe, so feel out of my depth when it comes to discussing the intracies of what they're capable of... and all the electronics that goes with that.
But I feel they hold great potential for the kind of work that I'm messing about with. I have a logical brain, but tend to find out what I need to know as required for what I want to achieve for a particular project.
So, at last back to this one! When I got the phones I took them apart and with a bog-standard multimeter realised that on turning the crank handle I was generating a/c power. My immediate reaction was "great - no need for modification, surely I can use this ready-made variable signal generator to control a sound... but how do I get the signal safely into the computer, surely this is where the Stamp comes in..?", hence my original post.
I will still probably want to get audio in and out of the phone(s), and maybe do something with the switch, but I've done that before,
Please keep in mind I am more of an artist than scientist - I really am after a simpler solution than a complicated one, and one I can easily figure out and source the parts for here in NZ, without it costing a bomb. I like using basic technology at the 'user' end to control complex programming behind the scenes - the everyday turned and twisted into something unexpected.
All of the posts on this so far have been very interesting, even if some have gone over my head. My most approachable one is the light-bulb / photo-resistor idea. I really don't care how accurate / stable etc the signal is - I don't think the audio will be that responsive or the average audience that bothered if the thing isn't tuned like an F1 engine to pick up every nuance of their turning - just to be aware that they have some control over what's happening is enough. Throw in a bit of visual too (the light bulb) and it a bonus!!!
sorry to waffle, hope my approach is a little clearer.
I guess my questions now (and please be as simplistic as poss!) are:
what spec of bulb should I get?
ditto with the photo-resistor
how about the a/d and the v-to-f?
got a wiring diagram!!!!!!?
sorry and thanks, you don't know how much I appreciate all this!
Jonno
At the risk of possibly being a bit presumptive, it doesn't look to me like the methods you've been offered here are quite "sinking in". All that I've looked at in this thread seem quite feasible, and many at quite a low cost. Perhaps you might want to give the following folks a call, as they're a good deal more local to you than we are. This is the Parallax Distributor in Aukland, New Zealand.
E-Source Ltd.
Auckland
Phone: Intl: +64211929950
Fax: Intl +64 9 521 3832
Web: http://www.esource.co.nz/
Email: sales@esource.co.nz
You might ask them to log onto this Stamp forum, and review this thread. Then, you can have a detailed conversation with them about what we're trying to present here. They may even have some other, better ideas we've not even considered, to help you.
Sometimes the written word doesn't "gel" or convey ones meaning as much as a personal conversation might. Above and beyond that, from my own perspective, as much as I might like to help you further, I honestly don't know where to go from here.
Mine may not be the best solution by any stretch, but for less than $10 or so (US or NZ) you could put my offering together, and see how it met your needs, or IF it met your needs.
In lieu of that "fancy telephone lamp" (which I mentioned primarily because of the flat top for maximum light emission from the tip of the bulb) you can use any small 110 volt lamp, possibly even from a discarded Christmas Tree string lamp. Unless I miss my guess, even a small 220 volt lamp might work, so long as the tube is well sealed. About the only other major part you will need is an analog to digital conversion chip. I'd like to think that E-Source (see above) can help you there.
I hope you find these thoughts helpful, as they are intended to be, and not dismissive!
Regards,
Bruce Bates
You need a base-line and this, it seems, would be that.
Post Edited (PJ Allen) : 12/7/2005 1:29:46 PM GMT
I'll get on to doing it now...
cheers, Jonno