I have a Keithley 610B Electrometer, they are pretty inexpensive on ebay. It has a tube front end (2x5886's running from about 20 volts), the amp that...
I would like to monitor a small bird nest with a simple electret mic. The mic would need to be weatherproofed. What's the best and least expensive way to do...
Would wrapping the mic in a plastic baggie work? The baggie and wires could be sealed in a number of ways and the membrane of the baggie is thin so should not...
I don't think you're missing anything. There's one on eBay right now that might be nearly unused! I'd bid but I suspect you're looking at that one. Heck the...
I would think placing the mic under a rain shield and in a zip-lock bag would do it. I bet a plastic bag won't attenuate the sound, especially if there's air...
The kind of light nylon cloth used for showerproof jackets would work too, might be better if there's a possibility of condensation. (Years ago we passed type...
I uploaded the 610b manual to the group files. Â You don't think a couple of your electrometer fet's would do it? ... From: charleswenzel <charles@...>...
They're hard to beat, leakage-wise. An op-amp has the nice feature of low offset and lots of loop gain but the FETs are certainly as good as the tubes and it...
The voltage at the Gate is 3.75vdc. I measured between the Gate and the positive input screw on the back of the transmitter. A reminder, the new Radio Shack...
Hi. I recently picked up a couple of kids 49 Mhz walkie talkies. What I'd like to do is place one in close proximity to a hummingbird feeder and listen on...
With 3.75 between gate and drain, I would guess the gate voltage relative to the source is 4.5 + 3.75 = 8.25 which suggests the circuit is indeed staying on....
I just stared at the schematic a couple of minutes and I think the only way it can stay on is if the second 1 uF (between the collector of the first transistor...
I've been right next to hummingbirds and I can't hear them! If I were to guess, I would say that they switch on the primary side of the audio transformer since...
Hi Charles, Thanks for the information! PIR detection was something I hadn't thought about. The trouble I seem to have with hummingbird detection is 1) very...
That eBay gadget looks perfect. You might want to seal the edges with silicone and place it under a cover, unless it's intended for outdoors. It looks like it...
I couldn't resist. Today, I picked up a Brinks Motion Activated replacement Motion Sensor and a wireless door chime. Unfortunately, I don't know much about...
The motion detector instructions say red motion sensor wire to all black lamp holder wires; white motion sensor wire to all white lamp holder wires and white...
Sounds like the red wire is HOT , when motion is detected and White is the neutral with the house wiring . The red wire must have 125 VAC on it when motion is...
Yes, I agree. I've seen red used as a second circuit or as switched AC. In this case, the sensor connects the black wire to the red when motion is sensed,...
To veer back towards the hummingbird part of the topic, you may be interested this motion detection webcam (it detects motion from the video from the camera)...
Thanks, Laurie. I did read about that before starting this project. The trouble with the software used is that it doesn't work well with earlier Win...
... i want help for my fire fighter robot sensors what type of sensor is better uv or ir to sense flame from 1.5 ft.approx. i already using an addition of...
I would think that near IR would be better for flame detection. Far IR using a PIR is also a possibility. I've been meaning to try another idea: It occurs to...
Here's the link I was really looking for http://www.superdroidrobots.com/shop/item.asp?itemid=121Â they sell the whole kit but as you say it's not cheap, $100...
