Search found 134 matches

by Chris Foley
Wed Apr 09, 2003 11:46 am
Forum: General Discussion
Topic: water sampler
Replies: 10
Views: 2422

Re: water sampler

Could you please provide more information?<p>* How many axes of motion do you want to have? Please describe. * If you want a circular motion going from sample to sample, how long should the rotating arm be? * Again, if you have a circular motion, what degree of accuracy do you need in placement? * D...
by Chris Foley
Sun Apr 06, 2003 4:22 pm
Forum: General Discussion
Topic: pic ICE
Replies: 2
Views: 843

pic ICE

Does anyone know about a good home-brew in-circuit emulator project for PICs, preferably minimum cost, operating off a PC platform? Any responses would be appreciated. Thanks.
by Chris Foley
Fri Apr 04, 2003 6:23 pm
Forum: General Discussion
Topic: Monitor temps
Replies: 10
Views: 2383

Re: Monitor temps

The multiple-input scanner is a good idea, and gives you the best of both worlds, especially if you can bunch your inputs up in groups geographically. Unfortunately, Anafaze doesn't make a 32-input scanner anymore. Their 16-point scanner, the CAS200, goes for around $110 a point, with the base unit ...
by Chris Foley
Fri Apr 04, 2003 9:05 am
Forum: General Discussion
Topic: Infrared data link
Replies: 2
Views: 996

Re: Infrared data link

How about slip rings? That's the "classic" solution. You fashion a few rings made of spring copper or some other conductive material around the rotating shaft, and hook up wires from the rings to your electronics on the top of the shaft. Then you make pieces of spring copper which are touching and c...
by Chris Foley
Sun Mar 30, 2003 7:07 pm
Forum: General Discussion
Topic: led flasher
Replies: 14
Views: 3290

Re: led flasher

NTE, a replacement parts reseller, calls the LM3909 their NTE876. Their website<p> http://www.nteinc.com/ <p>says there are two left at Mountain States Electronics, 2107 South College Avenue Fort Collins, CO 80526 United States, Tel 1-970-484-1044 1-877-325-1321. Since this is a one-off, I suppose i...
by Chris Foley
Sun Mar 30, 2003 6:54 am
Forum: General Discussion
Topic: Monitor temps
Replies: 10
Views: 2383

Re: Monitor temps

There are a number of ways to do this, Frank. But I'm not sure that thermistors are the way to go here, because a thermistor is a resistor whose resistance is dependent on temperature. If you use a standard two-wire connection to the thermistor, you have to take into account the resistance of the wi...
by Chris Foley
Sat Mar 29, 2003 3:02 pm
Forum: General Discussion
Topic: -first post- Need help with motorizing a pedal car
Replies: 5
Views: 1663

Re: -first post- Need help with motorizing a pedal car

May I make a suggestion, and I hope you don't take offense. This is the type of project where something can go wrong, and you might really regret it. For instance, the MOSFETs might short out, providing full speed/torque to motor, child panics, does a brain freeze for just long enough to float into ...
by Chris Foley
Sat Mar 29, 2003 2:40 pm
Forum: General Discussion
Topic: ceramic caps...
Replies: 2
Views: 1119

Re: ceramic caps...

Hi, Eye. You've got a couple of different types of caps there. The green ones are probably mylar (metallized polyester film) caps. The numbers on those refer to the number of picofarads. Remember 1000pF = 1nF (nanofarad), and 1000nF = 1uF(microfarad). The first two numbers are followed by the multip...
by Chris Foley
Fri Mar 28, 2003 8:29 pm
Forum: General Discussion
Topic: data-sheets
Replies: 8
Views: 2122

Re: data-sheets

Another source for datasheets on quite a few parts are NTE and the other repair shop sources.<p> http://www.nteinc.com/ <p>While their selection is somewhat limited, and their products are overpriced, you can frequently find something you can get and use today. Not even Digi-Key/FedEx can do that. J...
by Chris Foley
Sat Mar 22, 2003 7:39 pm
Forum: General Discussion
Topic: Stamp 2 & Relays
Replies: 14
Views: 3752

Re: Stamp 2 & Relays

Thanks, Ron. You're right. The rule of thumb for using a transistor as a switch is Ib=Ic/10. However, although minimum Hfe is 30, typically they go from 100 to 250. A bit of soft saturation seems to be less of a hazard (especially for this light of a load) than stressing out the Stamp by drawing too...
by Chris Foley
Sat Mar 22, 2003 7:30 pm
Forum: General Discussion
Topic: Help with invention?
Replies: 6
Views: 2102

Re: Help with invention?

They're already out there. Take your choice, Chess:<p> http://www.laminationplus.com/laminators/1600pp.shtml <p>Allegedly does 128 pages of 20# paper -- 3-hole punch, but very manual (ouch, my aching palm!), and<p> http://adss.net/1002062.asp <p>40 to 50 sheets of 20# at a time, but it's fully elect...
by Chris Foley
Thu Mar 20, 2003 5:14 pm
Forum: General Discussion
Topic: problem in writing PID with C program
Replies: 16
Views: 4808

Re: problem in writing PID with C program

Hi, Will. I'm sorry -- I didn't mean to get on your nerves. All I meant to say was I don't think I can help this guy, and he looks like he needs somebody to do this for him. I was wondering if you wanted to offer your services -- I'm definitely not interested at this point. I'm an Engineering Tech (...
by Chris Foley
Wed Mar 19, 2003 3:23 pm
Forum: General Discussion
Topic: Electronic Supplier
Replies: 5
Views: 1601

Re: Electronic Supplier

Herbach and Rademan is a good source for motors. Check out:<p>http://www.herbach.com/
by Chris Foley
Wed Mar 19, 2003 3:16 pm
Forum: General Discussion
Topic: problem in writing PID with C program
Replies: 16
Views: 4808

Re: problem in writing PID with C program

It's all yours if you want it, Will. The correspondent seems to need someone to help him. Free advice and $2.50 will get you a cup of coffee at Starbucks, so here goes...<p>If I were doing this, I would make an electronics go-cart without a drive motor, and put it on an exercise treadmill. By affixi...
by Chris Foley
Wed Mar 19, 2003 6:39 am
Forum: General Discussion
Topic: problem in writing PID with C program
Replies: 16
Views: 4808

Re: problem in writing PID with C program

If you are unable to download the second link, you should install Adobe Acrobat Reader. This free software will allow you to read .pdf files. This free software is available at:<p>http://www.adobe.com/products/acrobat/readstep.html<p>[ March 19, 2003: Message edited by: Chris Foley ]</p>