Search found 82 matches
- Tue Dec 25, 2012 9:57 am
- Forum: General Discussion
- Topic: Would the US electrical code allow this ?
- Replies: 9
- Views: 6281
Re: Would the US electrical code allow this ?
If you want more light than what a typical lighted switch provides you can just use a standard wall mounted "three-way" (Single-Pole, Double-Throw SPDT) switch. Three-way switches are typically used to control a circuit (like lights) from more than one location. Here though you are control...
- Mon Dec 03, 2012 3:03 pm
- Forum: General Discussion
- Topic: Light dependent resistors...
- Replies: 7
- Views: 4415
Re: Light dependent resistors...
never mind
- Sat Jun 23, 2012 12:04 pm
- Forum: Projects & Kits
- Topic: Bat Detector
- Replies: 2
- Views: 13581
Re: Bat Detector
A few more comments on the circuit. 1. The quoted opamp gains are way off. At say 50KHz the maximium gain for the particular opamp is only 20x since the Gain Bandwidth product for that opamp is 1MHz. For the pair of opamps the maximum gain is therefore ~400. At DC the gain is unity. 2. The feedback ...
- Sat Jun 23, 2012 11:46 am
- Forum: General Discussion
- Topic: Bat Detector
- Replies: 6
- Views: 4797
Re: Bat Detector
It should be pretty easy to make a detector that is both heterodyne and digital. For the heterodyne circuit in the 2011 N&V you would just need to add a digital divide chip (e.g., CD4024B) and perhaps a single resistor to limit the output to the ear piece. Put a DPST switch in that shunts the am...
- Sun Sep 18, 2011 8:56 am
- Forum: General Discussion
- Topic: Generator Question
- Replies: 20
- Views: 11435
Re: Generator Question
For any small engine I would assume that the general replaceables need to be replaced. (Always go with the simplest and cheapest fixes first.) New plug(s), new air filter, and in particular, a new fuel filter. If the fuel filter is starting to plug up the engine will run lean but may still seem to o...
- Thu Sep 15, 2011 12:49 pm
- Forum: General Discussion
- Topic: Color scanners and copiers...
- Replies: 4
- Views: 2775
Re: Color scanners and copiers...
Illuminate with white and detect with three sensors, ones for red, blue and green. Not that hard (and the detectors don't have to be looking at the same spot at the same time). Or, if the detector responds well to all colors, just use three sensors with different color filters. Black and white scann...
- Mon Jul 25, 2011 3:23 pm
- Forum: General Discussion
- Topic: Carbon Monoxide?
- Replies: 9
- Views: 4224
Re: Carbon Monoxide?
1. I would think that air supply is one big difference. A gas range has an exposed flame with lots of access to air (adequate air is needed to reduce CO2 production). A hot water heater places the flame inside an enclosure which increases the chances of an inadequate air supply. 2. Visibility probab...
- Mon May 30, 2011 8:04 am
- Forum: Projects & Kits
- Topic: Bat Detector
- Replies: 2
- Views: 13581
Bat Detector
Very interesting article, one that I might give a try. Two points / questions though. In Figure 5 (Board Layout) it looks like there should be a cut in the Vero board trace underneath capacitor C4. Also, there is no connection to the battery negative. There should be a connection between the trace i...
- Sun May 29, 2011 2:02 pm
- Forum: General Discussion
- Topic: Commenting on article in Nuts & Volts
- Replies: 6
- Views: 3524
Commenting on article in Nuts & Volts
Does Nut & Volts have a place where you can comment on articles? Some years back there was an article on measuring the speed of light that I always wanted to comment on. There were typos in the data table and the technique spent a lot of time dealing with gate delays when it wasn't necessary. In...
- Sun May 29, 2011 1:57 pm
- Forum: General Discussion
- Topic: FREE Phone number lookup,.... PHONY
- Replies: 2
- Views: 2338
Re: FREE Phone number lookup,.... PHONY
Basically there is nothing illegal about lying. "Truth in advertising" laws often don't apply to online content, and even for traditional advertising venues, lying is common.
- Fri May 27, 2011 1:25 pm
- Forum: General Discussion
- Topic: The "Great' lawnmower legal settlement
- Replies: 15
- Views: 7292
Re: The "Great' lawnmower legal settlement
It is not like the tech writers from the 60's, 70's etc weren't above wildly exaggerating claims either. Over claiming car engine horsepower is a decades old 'trick" of car makers. Extravagant claims of audio power ratings have been around since the 50's. Is that watt rating "peak" or...
- Wed May 04, 2011 3:17 pm
- Forum: General Discussion
- Topic: Flipping video
- Replies: 12
- Views: 8511
Re: Flipping video
jimmy- The cameras are actually looking through portholes, and lighting becomes a problem with using a mirror. Why? A mirror reflects better than 95% of the light that hits it so there isn't enough attenuation to be a problem. The mirror can be within an inch or two of the camera's lens, and the mi...
- Tue May 03, 2011 5:15 pm
- Forum: General Discussion
- Topic: Flipping video
- Replies: 12
- Views: 8511
Re: Flipping video
You said a mirror won't work. Why not? Just point the camera at a small mirror and point the mirror at the line.
Usually the obvious solution is the best solution.
Usually the obvious solution is the best solution.
- Sun May 01, 2011 9:47 am
- Forum: General Discussion
- Topic: Moisture vs Resistance
- Replies: 11
- Views: 6111
Re: Moisture vs Resistance
I would suspect that the meter they are using is similar, if not identical, to a wood moisture meter like http://www.homedepot.com/webapp/wcs/stores/servlet/ProductDisplay?storeId=10051&productId=100651808&langId=-1&catalogId=10053&ci_src=14110944&ci_sku=100651808&cm_mmc=shop...
- Sun Apr 24, 2011 9:22 am
- Forum: General Discussion
- Topic: low fuel alert
- Replies: 26
- Views: 10356
Re: low fuel alert
Perhaps just a low pass filter? Resistor in series followed by a cap to ground. Pick the values so that RC is say 10 seconds. 10Meg resistor and a 1uF cap seems about right. Take the input to the alarm's comparator from between the resistor to cap connection. This won't give any hysteresis but it wi...