Hey guys, I was hoping someone could help me out for a sec.
We're currently doing some research for a school project on capacitive sensors, and we wanted to make a theremin as an experiment. For that we needed a coil. Our professor found one for us, but it was already attached to a breadboard with a bunch of other components. He said it was from someone else who had also been looking into capacitive sensing and had built it from an instructable.
So, my question today is: Does anyone know WHICH instructable? Do you recognise the component? If it's for something useful we would like to try it out before disassembling it.
And if you can't identify it, we'd still like to figure out what that tiny black and red cylinder is. Someone suggested it was a heat sensor but last time I checked they usually looked like metallic prods or black half-cylinders.
Yes, the black thing is an inductor wound on a ferrite bobbin and covered with heatshrink. The numbers indicate its value.
All you have is an inductor, a common signal diode and some capacitor and resistors. In the absence of the active components, it offers absolutely no information whatsoever as to what the larger circuit was, so just use the parts.
syverlauritz:
And if you can't identify it, we'd still like to figure out what that tiny black and red cylinder is. Someone suggested it was a heat sensor but last time I checked they usually looked like metallic prods or black half-cylinders.
by now, it has been identified. alas. it is a diode or PN junction. interestingly it IS sensitive to heat and can be used as the basis of a temperature sensing device.
nothing to do with the therimin. just wanted to mention it since you brought it up.
If it has clearly marked on it "4148" - as has been stated - then it is a (version of a) 1N4148 - just like the few dozen in my parts drawer that are labelled in this manner.
(There is simply insufficient space on the circumference of the diode body to write "4148" in one line.)
So I guess we'll just disassemble this scavenged breadboard then. We're getting pretty confident on CapSensors, and I guess the conclusion we're coming to after a week of researching them is: Unless you really really really HAVE TO, don't use them for DIY projects. They're wildly unstable and seem to require perfectly controlled environments to give any consistent readings. Even using an insulated cable doesn't fully solve it, as even room humidity will have an impact on the reading.
Like I said, I just wanted to know if anyone recognized what instructable tutorial this was from. If anyone DID recognize it, we could just plug it up and have a play with it.
As for doing my research - I'm not quite sure how else I could figure this one out, other than asking on a forum with an attached photo?
A theremin built with hetrodyning oscillators is -not- a trivial task. You think you are having problems with capacitive sensing, thrown in the drift of an inductor and a handful of more components in the oscillator.
syverlauritz:
Like I said, I just wanted to know if anyone recognized what instructable tutorial this was from. If anyone DID recognize it, we could just plug it up and have a play with it.
Did you ever have a look at any "instructable" project ?
Clearly not.
The former student (in mad science, no doubt) will probably an Arkham resident by now, after trying to get that instructable to work.
Most items on that site promise miraculous results if you follow the instructions.
You won't be told why you "have to" do that, just do it.
If you get in trouble getting things to work, you're on your own.
Don't waste your valuable time over there.
Alas, it is relatively non-trivial to put content of any significant complexity into Instructable form, and many of the results are less than wonderful. (Oh - wait! That's true of ANY method of publishing! Go figure...)
The Inductor pictured looks to me to be of a rather high value for Theramin-like projects, which normally work by allowing the capacitance of the body to interfere with an RF oscillator. 10000uH (or even 10000nH) inductors of the style shown are more often used in things like power supplies.
Well, then you are the exception to the rule, westfw.
And my apologies for generalizing, please don't feel offended.
I did have a look at some of your entries there and you do seem to explain what's going on and be actually right with that.
I doesn't help getting rid of my absolute disgust of that site, though.
I agree with your remark on the inductor.
There's a wide range of inductors (same as with capacitors) and each has it's best properties / uses.
OP has an opportunity to learn here, and i guess that's what he came here for.
So I guess we'll just disassemble this scavenged breadboard then. We're getting pretty confident on CapSensors, and I guess the conclusion we're coming to after a week of researching them is: Unless you really really really HAVE TO, don't use them for DIY projects. They're wildly unstable and seem to require perfectly controlled environments to give any consistent readings. Even using an insulated cable doesn't fully solve it, as even room humidity will have an impact on the reading.
Like I said, I just wanted to know if anyone recognized what instructable tutorial this was from. If anyone DID recognize it, we could just plug it up and have a play with it.
As for doing my research - I'm not quite sure how else I could figure this one out, other than asking on a forum with an attached photo?
to answer the more general question of how to get more help. the subject line is often key. it is obvious the subject is a theriin and not an instructable.
put thermin on the subject line. chances are vastly improved
kind of a follow-up, but are you going the arduino/termimin route or the more traditional one ?.
