Search found 12 matches
- Mon Aug 04, 2003 10:11 am
- Forum: General Discussion
- Topic: Buying a digital multimeter
- Replies: 16
- Views: 7684
Re: Buying a digital multimeter
If you want a good one (as opposed to a $5 one), definitely check out the resale market. Normally eBay is expensive, but there is so much surplus equipment out there (I think after all the .com failures) you can often be the only bidder on an item and get it really cheap). Also think about whether y...
- Mon Aug 04, 2003 8:23 am
- Forum: General Discussion
- Topic: Any hints on how to buld pedometer?
- Replies: 13
- Views: 5920
Re: Any hints on how to buld pedometer?
30 meters (100 ft) is about right as a worst case error for GPS. That is the size of a standard U.S. suburban 1/4 acre lot, which I would think is close enough for use as a pedometer. As you acquire more satellites the accuracy gets better, down to 15 feet in my experience.<p>Surveyors use something...
- Mon Jul 28, 2003 11:03 am
- Forum: General Discussion
- Topic: electric meter rotor rpm vs power
- Replies: 5
- Views: 3195
Re: electric meter rotor rpm vs power
Thanks; I'll check it out and see if I get something reasonable on mine.
- Mon Jul 28, 2003 8:15 am
- Forum: General Discussion
- Topic: electric meter rotor rpm vs power
- Replies: 5
- Views: 3195
electric meter rotor rpm vs power
Does anybody know how to take the rpm of the rotor on an electric meter and convert it to kilowatts? I have found general info on the net that says the meters are calibrated with a strobe, but nothing specific that says how you know many RPMs = 1kW (or how many rotations = 1 kWH).
- Fri Jul 25, 2003 7:45 am
- Forum: General Discussion
- Topic: Question about previous question
- Replies: 6
- Views: 3649
Re: Question about previous question
Your only other option to using a laser printer is to print and then copy with a copier where they will let you put in your own paper.
- Thu Jul 24, 2003 12:46 pm
- Forum: General Discussion
- Topic: Bike spedometer
- Replies: 10
- Views: 4925
Re: Bike spedometer
If your willing to spend $20 for a cheap digital voltmeter or surplus panel meter, then all you need is a way to generate an average voltage proportional to the rotation speed. For example, a magnet, coil, diode, and capacitor. The faster the wheel rotates, the higher the voltage and more frequent w...
- Thu Jul 17, 2003 2:12 pm
- Forum: General Discussion
- Topic: Project
- Replies: 6
- Views: 4569
Re: Project
I would do it with a Basic Stamp and a temperature sensor. You don't need a micro lab, just a PC and their cheapest getting started setup with the whole development environment right there on the chip/board that's going to be the final product.<p>You can do a discreet design with logic chips, etc, b...
- Thu Jun 26, 2003 1:46 pm
- Forum: General Discussion
- Topic: Timer Chip
- Replies: 5
- Views: 3542
Re: Timer Chip
a 556 timer chip will work, as long as it doesn't have to be too accurate
- Thu Jun 05, 2003 2:47 pm
- Forum: General Discussion
- Topic: Model Rocket Lauch Timer
- Replies: 9
- Views: 4363
Re: Model Rocket Lauch Timer
I don't have time to draw a schematic but I can tell you how to hook it up. If you know enough to know to use cascaded 555s then I think you can figure out the details.<p>Look at Figure 1 in http://www.national.com/ds/LM/LM555.pdf <p>Connect a normally open pushbutton switch to ground to the input (...
- Tue Jun 03, 2003 2:13 pm
- Forum: General Discussion
- Topic: Extermely High Speed Timer?
- Replies: 3
- Views: 2261
Re: Extermely High Speed Timer?
Assuming for descriptive purposes that when your transmitted and received signals are active it represents a logic "1", if you transmit a pulse which is longer than the max round trip delay, and feed the transmitted and inverted received signal into an AND gate, than you will get a pulse o...
- Tue Jan 14, 2003 1:59 pm
- Forum: General Discussion
- Topic: pic serial data
- Replies: 4
- Views: 3274
Re: pic serial data
How about a VCO (voltage controlled oscillator) set to go between the two frequencies based on high or low input? Or two 555s set to the two frequencies with gates to choose between them based on high or low input?<p>The modems are hard to find because no one uses them anymore; the hams use software...
- Mon Jun 17, 2002 2:02 pm
- Forum: General Discussion
- Topic: Cordless phone range
- Replies: 16
- Views: 9374
Re: Cordless phone range
10 blocks to the mile in some parts of the country, 12 in others. In NYC blocks are rectangular, so the direction matters.<p>How about GPRS radios?