Joined: Jan 14, 2010 Posts: 5581 Location: Moon Base
Audio files: 705
Posted: Sun May 27, 2012 4:40 am Post subject:
little chime Subject description: simple circuit that creates a 'ping' at an interval.
Í wanted a circuit that produces a little chime like ping once in a while. Actually I want a bunch of those
and make them solar powered (and maybe have them turn on at night). Anway this is what i came up with.
It's pretty straight forward: 2 oscillators 'mixed' with a NAND provide the sound, Then there a 3rd oscillator
which (with the current component values) turns on once every 3.5 - 4 minutes. You could change the
values or add a pot if you want a different interval time.
The on time is much shorter then the off time and it's followed by a simple envelope generator to create
a short attack and long decay. This in turn drives a transitor which functions as a VCA. And then
there is one more transistor used to drive the (piezo) speaker. It probably works with a normal speaker
aswell, but you'll have to put a resistor in series, and maybe need a slightly heavier transistor.
I also added a jumper to bypass the VCA section, which is usefull for tuning, but you could also use
this point for an external trigger.
I wasn't sure if I should post this in the lunetta section (or even post it at all) but it IS a simple circuit with
a CMOS chip at it's core.
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Joined: Nov 10, 2011 Posts: 878 Location: Lancashire, England
Audio files: 14
Posted: Sun May 27, 2012 5:51 am Post subject:
Of course you should post it Simple circuits like yours are the core of anything more advanced. I'd like to get some sound files of it, from reading your description, I imagine it sounds quite nice That little transistor stage is interesting as well, any more info on the VCA? I think I see how it works but I'm not sure. _________________ As a mad scientist I am ruled by the dictum of science: "I could be wrong about this but lets find out"
Joined: Jan 14, 2010 Posts: 5581 Location: Moon Base
Audio files: 705
Posted: Sun May 27, 2012 9:10 am Post subject:
Little Chime Demo
Ok I recorded a little demo using the jumper for manual triggering. I think it does sound a bit better through
the speaker which is what it's intended for. And I just found out it isn't even a piezo but just a little 130 ohm speaker.
Not much to say about the VCA unless you want all the fine details (and I don't know those). It's something
like a higher voltage on the base, or i think i should talk in currents here, causes a bigger current to flow
from from Collector to Emitter, so the signal get's louder. But I'm pretty sure there are people here who could
tell you exactly what's going on with some formulas and stuff like that
Posted: Sun May 27, 2012 10:08 am Post subject:
Re: Little Chime Demo
PHOBoS wrote:
But I'm pretty sure there are people here who could
tell you exactly what's going on with some formulas and stuff like that
No need to make the concept complicated: The voltage on the base controls how much of the signal on the collector gets to the emitter. You could also consider it as a simple voltage controlled resistor. See the MFOS WP20 VCA and some of the Roland 909 voices.
And don't be surprised if someone accuses you of stealing the design _________________ Revenge is a dish best served with a fork... to the eye
Joined: Nov 10, 2011 Posts: 878 Location: Lancashire, England
Audio files: 14
Posted: Sun May 27, 2012 10:17 am Post subject:
wow that can get really bell-like lovely! ... and yet it sounds oddly harsh too. Certainly the kind of noise which makes you sit up and take notice (I assume from what you said this may be its purpose?)
Also, thats along the lines of what I was thinking regarding the little VCA, without them equations I think I'd have to experiment to fully understand. _________________ As a mad scientist I am ruled by the dictum of science: "I could be wrong about this but lets find out"
Joined: Nov 10, 2011 Posts: 878 Location: Lancashire, England
Audio files: 14
Posted: Sun May 27, 2012 10:24 am Post subject:
Re: Little Chime Demo
richardc64 wrote:
You could also consider it as a simple voltage controlled resistor. See the MFOS WP20 VCA and some of the Roland 909 voices.
OH it all makes sense now! Thankyou
Also I misred the design a little bit, I thought the diode pointing down was connected to Ud1 output, but thats just the jumper going to +V, the lines simply cross there
Anyways, it makes more sense now thanks to you both _________________ As a mad scientist I am ruled by the dictum of science: "I could be wrong about this but lets find out"
Joined: Feb 27, 2008 Posts: 156 Location: Roma, Italy - London, UK
Audio files: 13
Posted: Mon May 28, 2012 11:09 am Post subject:
Re: little chime Subject description: simple circuit that creates a 'ping' at an interval.
PHOBoS wrote:
Í wanted a circuit that produces a little chime like ping once in a while. Actually I want a bunch of those
and make them solar powered (and maybe have them turn on at night). Anway this is what i came up with.
Joined: Jan 14, 2010 Posts: 5581 Location: Moon Base
Audio files: 705
Posted: Mon May 28, 2012 12:10 pm Post subject:
Re: little chime Subject description: simple circuit that creates a 'ping' at an interval.
aerogramma wrote:
love it! what causes the change in pitch?
The pich is changed by adjusting the two potentiometers (I used 2 little trimpots with a shaft myself).
So I did that manually in the demo, it doesn't change by itself . You could make some circuit that does that
or add some LDR's to make the frequency light dependent, but my idea was to make a couple of them and tune
them all different but in tune with each other. Because of tolerance in components they will all chime at
a slightly different interval, causing a slowly changing sequence. _________________ "My perf, it's full of holes!" http://phobos.000space.com/ SoundCloudBandCampMixCloudStickney SynthyardsCaptain ColliderTwitchYouTube
Joined: Jan 14, 2010 Posts: 5581 Location: Moon Base
Audio files: 705
Posted: Wed Jun 20, 2012 5:05 am Post subject:
I was just watching that video on youtube, love it
I'm always interested in little solar devices and still want to make some sort of solarpowered orchestra.
I also did a little drum thingy but my problem is usually finding a useful motor. Do you have any idea
of the ouput of your solarpanels ? (voltage/current) they look pretty big
as it is now the little chime circuit does not seem to work on the solarpanels I have. Thinking it might
have to do with the speaker drawing too much current, I hooked up 3 AA batteries (I have 4.5V solar panels)
but that didn't seem to work either. So I probably have to make some adjustments to the circuit.
It should be possible though,. since I've done a solar powered CMOS circuit in the past which also has a
small speaker (I think it's 8 ohm but with a series resistor) and that works great, so current draw shouldn't actually
be a problem. Offcourse I'd still need batteries if I want to use it at night.
Here's a video showing that circuit, it also has the drum thingy
Do you have any idea
of the ouput of your solarpanels ? (voltage/current) they look pretty big
I cant help you with circuit design as Im completely clueless .
I am however interested in making solar powered lunettas, so will watch your progress with interest, ATM Im otherwise occupied so solar will haveto wait.
The panels I have are all different, I just join them up if I need more power. That being said the BEAM solar engine Im using works with any size, even tiny calculator cells. Reason being charge is stored in a Cap. and drained when a preset voltage is reached. I want to use this method with Lunettas for some burst like modules.
This is the circuit:
http://www.beam-online.com/Robots/Circuits/1381.html
Nice vid.
Whats going on with the wind chime one? What is moving the ball?
[quote="nathanxl"]
http://www.beam-online.com/Robots/Circuits/1381.html
/quote]
nice solar sound stuff here !
But I hate these1381 solar triggers. Don't know why they are so popular: they are hard to fin (in Germany), expensive ( compared to transistors & 4xxx CMOS) and single source (as far as I know. A definite No-Go for Lunettics. I've built lots of solar powered motorized stuff with a simple transistorized circuit ( see pdf). Who will redesign it with a 4007 instead of
the discrete transistors ? I'm sure it's possible.
BTW : circuits that have the motor load in the path that loads a timing cap
( like this 1381 and FLED circuit ) show trigger problems when motor collector position is not well defined; that's why I use a 3rd transistor for the motor.
Yes I too found it difficult to source the 1381s. Although I was aware thatthere were other ways to fry that fish... I didnt, and still dont , have the EE chops to design my own solutions. That circuit of yours Electrouwe looks very good.
So by adjusting the resistor values the stored voltage is changed?
Y
So by adjusting the resistor values the stored voltage is changed?
yes, normally you set the trigger voltage as high as possible to store max. energy, but if you set it too high the solar cell might not reach this voltage under worse light conditions and your gadged behaves rather dead then.
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