Hi Charles ... you Sir are a genius .... I've constructed the circuit as per your schematic and it sounds perfect. I don't even have to play with the chime...
Well, thanks for the compliment but I actually discovered that approach by accident when I added a little beeper to a train scale I was working on. Imagine my...
The wireless thermometer is nearly complete. I now have a housing against solar radiation and for weather protection, so I can place the transmitter where I...
I think I might try NiCad batteries since they are forgiving of overcharge; they just get warm. There are some pretty cheap panels out there. For example: ...
I have an old Oregon Scientific wireless thermometer, the AAA batts last a couple of years or more, lithiums would last even longer so I question the return on...
You have a point. A couple of D cells would probably hold up for their typical shelf life of a decade or more. ... last a couple of years or more, lithiums...
Hi Charles, I need your help in building a message board to show some message on led matrix, which I can change with the help of computer's serial port. ...
You need to shield the vane when it is grounded or it will just charge up and exhibit no voltage when it is ungrounded. Think of it this way: if I connect a...
Charles, Your last approach reminds me of a NASA Tech Brief on a Hybrid Electric-Field Sensor. (June 2002 I believe) I will try to see if I have a PDF of that....
Charles Thanks for replying. I was seeing it as similar to measuring the voltage across a capacitor that has one end grounded, and the other connected to high...
It's a good analogy only that resistor is too big to be practical. I've seen projects that claim to work that way but I would imagine that random air ions...
... I'm in the same boat. I just tried to log on and either I or they can't remember my login. (probably me) ... Electric-Field Sensor. (June 2002 I believe) ...
Eric sent me the pdf and it is exactly what I was imagining. It suggests a back-and-forth movement instead of a rotary movement for the shield. One antenna...
I haven't thought into this very far, but there used to be class of electrometers called vibrating reed electrometers. I think you can still get one from a...
You just gave me an idea; how about an old telephone ringer? The clapper moves pretty far and extending the arm would give a nice swing range. A low frequency...
Campbell scientific make a reciprocating shutter mill http://www.campbellsci.com/electric-field-sensor but it uses a stepper. I still like the disk drive voice...
That sounds perfect. I got the ringer from an old phone working, too. I added several inches of steel wire and it really "goes to town" with the right drive...
As i got back home from my weekly trip to the er ,,, um strip club. i notice my blender dont work. Hey im an electronics dude , i can fix it. I open it up to...
... and a flip flop it could be self oscillating. ... got the ringer from an old phone working, too. ... A few years ago I built a vibrating capacitor...
I like that approach since it does seem really simple to build, a real stumbling block for most static charge detectors. I'm still hooked on the idea of a...
In my design, any E-field frequency above the plate wiggle frequency is integrated towards zero. It looks like a digital filter with deep notches every even...
The quadrature thing works on the fact that sin^2 + cos^2 = 1. So, if you square the output from each speaker and sum them, the answer is proportional to the...
