Search found 26 matches

by skrallman
Wed Feb 11, 2004 12:00 am
Forum: General Discussion
Topic: Intro to Microcontrollers HELP
Replies: 8
Views: 1600

Re: Intro to Microcontrollers HELP

This maybe of some help. This link has a comparison between the oopic and basic stamps.<p>I'm a beginner, too. I've got an oopic and I've played with the pic16F84. I found the object oriented programming of the oopic easy to use, but it's expensive. I'm always afraid I'll smoke it. The oopic can be ...
by skrallman
Sat Jun 28, 2003 4:45 pm
Forum: General Discussion
Topic: Ni Cad chargers help
Replies: 15
Views: 3691

Re: Ni Cad chargers help

What about using one of the charge controller ic's?
The max712/713 are one example. They'll send you a free sample and there are several examples out on the internet of chargers people have made that can help guide you.
I've been working on a 13.2V charger.....haven't got it working yet.
Scott
by skrallman
Fri Jun 13, 2003 7:19 am
Forum: General Discussion
Topic: Battery running times
Replies: 4
Views: 1251

Re: Battery running times

For lead acid batteries, that amp-hour rating is usually cited over a 20 hour period. For example, 10 Ahrs/20hrs = 0.5A . If you drew 0.5A out of the battery, you would expect to get the full 10Ahrs out of it. But, the capacity decreases when you put heavy loads on it, expecially for lead acid batte...
by skrallman
Sat May 03, 2003 5:22 pm
Forum: General Discussion
Topic: Drill Battery Pack Dies Suddenly!
Replies: 5
Views: 1096

Re: Drill Battery Pack Dies Suddenly!

WildBoar, I've had a few battery packs made, and made a few myself from surplus battery packs. You might save a little if you DIY, but typically they pack those batteries in there pretty tight which makes it a big hassle to get it all back in. I think it really comes down to how much you like to tin...
by skrallman
Thu May 01, 2003 10:17 am
Forum: General Discussion
Topic: Temperature readings into a PC?
Replies: 16
Views: 2772

Re: Temperature readings into a PC?

Stuffed,
You've already got alot of good info here, but you may want to check out this page DS1621 pc thermometer
Its a simple circuit, he gives you the software and it will log to a .txt file.
good luck
Scott
by skrallman
Fri Apr 25, 2003 7:49 am
Forum: General Discussion
Topic: need advice for multimeter with pc interface
Replies: 6
Views: 1424

Re: need advice for multimeter with pc interface

Thanks everyone, I ended up getting the RS meter. MrAl: Good point about two inputs. I looked around, but the price seemed to go up dramatically. Does anyone know why most of the meters log at only 1 sample/sec? If you were to write your own program could you increase the sample rate, or is the mete...
by skrallman
Wed Apr 23, 2003 7:50 pm
Forum: General Discussion
Topic: do it yourself ekg
Replies: 12
Views: 2427

Re: do it yourself ekg

Thanks SmallWorld. I did check out LabJack, but like Sam, its more than I want to spend. However, you got me looking around and I found another product by Dataq: 10 bit, 4 channel, +-10v and 240 samples/sec, and software for $25. Not as versatile, but sounds good for the price.<p>Sam, whats the samp...
by skrallman
Wed Apr 23, 2003 7:41 am
Forum: General Discussion
Topic: do it yourself ekg
Replies: 12
Views: 2427

Re: do it yourself ekg

Thanks Sam. I'll give that a try. My scope is an old surplus unit, that may be problem. I do see the EKG trace, but it happens too fast to study it. Is the student version a of LabView the same as their free evaluation version? I've been to their web site, but its a 91.5MB download ! Do you have a L...
by skrallman
Mon Apr 21, 2003 9:00 pm
Forum: General Discussion
Topic: Resources for Switching Power supplies
Replies: 11
Views: 2203

Re: Resources for Switching Power supplies

Radio Shack has a book for about $8 called Building Power Supplies. I think it has three switching supply projects. It has a little background theory, but mostly it just gives you the equations for sizing the components. I found it very helpful, but I'm a hobbiest, not an EE.
Scott
by skrallman
Thu Apr 17, 2003 11:31 am
Forum: General Discussion
Topic: do it yourself ekg
Replies: 12
Views: 2427

Re: do it yourself ekg

Hi Sam, I'm not an EE either. I'm a civil/environmental engr., but I like to tinker. Labview is a data logging software, isn't it? I tried to view my ekc signal on my oscilloscope, but it doesn't work very well. I think the problem is that I can't adjust the time scale to be slow enough. I think a d...
by skrallman
Thu Apr 17, 2003 9:06 am
Forum: General Discussion
Topic: Cheap sound generatot
Replies: 3
Views: 927

Re: Cheap sound generatot

Well, I don't know about porche or viper sounds, but there is an old sound generator chip sn76477. There ia a radio shack app note and a popular electronics article about it. They describe a circuit for race car engine sounds, but I've never heard it. Here is a site with the data sheet, app notes an...
by skrallman
Wed Apr 09, 2003 9:15 pm
Forum: General Discussion
Topic: water sampler
Replies: 10
Views: 1597

Re: water sampler

Another motor that comes to mind is a RC servo motor. They can be easily modified to rotate continuously, they're geared low, have quite a bit of tourqe and they're cheap. I think you can get them for as little as $9 at servocity.com. People use them alot for robots so there is also alot of info abo...
by skrallman
Wed Apr 09, 2003 8:27 pm
Forum: General Discussion
Topic: do it yourself ekg
Replies: 12
Views: 2427

Re: do it yourself ekg

In case anyone wants to read about it:<p>http://www.sciam.com/article.cfm?colID= ... 9EC588EF21
by skrallman
Wed Apr 09, 2003 8:25 pm
Forum: General Discussion
Topic: do it yourself ekg
Replies: 12
Views: 2427

do it yourself ekg

The June 2000 issue of Scientific american had an article about a do it yourself EKG. Has anyone built this circuit? I've built the circuit, but would like to compare notes with someone.
Scott
by skrallman
Wed Apr 09, 2003 2:26 pm
Forum: General Discussion
Topic: binary clock
Replies: 5
Views: 866

Re: binary clock

I just searched google. There seemed to be alot. This looks like a good one.
http://www.namon.net/binary.html<p>There are also clocks for your windows desktop.
Scott