Search found 134 matches

by Chris Foley
Tue Mar 18, 2003 4:10 pm
Forum: General Discussion
Topic: problem in writing PID with C program
Replies: 16
Views: 4683

Re: problem in writing PID with C program

The Sharp GP2D12 is a distance sensor with an analog output -- cool chip, I want one! It senses distance, and outputs an analog voltage proportional to how close the object is, from 10cm. to 80cm. From the data sheet, using a +5V supply, the output voltage will be between 0.4V and Vcc-0.3V. I would ...
by Chris Foley
Mon Mar 17, 2003 10:07 pm
Forum: General Discussion
Topic: problem in writing PID with C program
Replies: 16
Views: 4683

Re: problem in writing PID with C program

Your project hardware spec still isn't clear -- I think you're talking about using a PC with one of those multi-I/O board setups (8255 is a programmable peripheral interface, 8254 is an 8-bit timer/counter IC).<p>If you're looking for something you can just plug in to do your job, sorry -- neither o...
by Chris Foley
Mon Mar 17, 2003 6:10 am
Forum: General Discussion
Topic: problem in writing PID with C program
Replies: 16
Views: 4683

Re: problem in writing PID with C program

Motorola PID loop routines for 68HC11 processors with PWM output
http://e-www.motorola.com/brdata/PDFDB/docs/AN1215.pdf<p>Engineering School assignment on PID loops
http://godiva.eos.uoguelph.ca/~raudette ... lerlab.pdf<p>Happy hunting.
by Chris Foley
Fri Mar 14, 2003 6:48 pm
Forum: General Discussion
Topic: Panic Switch
Replies: 7
Views: 2027

Re: Panic Switch

I believe you can do the whole thing from Radio Shack. Get a 4 AA battery holder which will fit in your enclosure, giving you a 6VDC supply. While you're there, get the LEDs with panel mounting hardware, some switches, a logic-level SCR, and some 220 ohm and 10 K ohm 1/4W resistors. From the red lea...
by Chris Foley
Thu Mar 06, 2003 4:55 pm
Forum: General Discussion
Topic: CTR Monitor VGA switch interface?
Replies: 9
Views: 2056

Re: CTR Monitor VGA switch interface?

Hi. If you don't mind something of a low-tech solution, have you looked into bimetallic thermal snap switches? These automatically open and close at preset temperatures, and I'm sure there's one that will do the job for you. The fan will cycle while the monitor's on, but if you choose the thermal sw...
by Chris Foley
Sat Feb 22, 2003 10:53 am
Forum: General Discussion
Topic: Stamp 2 & Relays
Replies: 14
Views: 3636

Re: Stamp 2 & Relays

Hi. Welcome to the "real world" of actually making all these electrons actually do something. A wonderful place it is, and one that isn't taught very well in engineering schools. Maybe the teachers are spending too much time teaching SPICE simulations. SPICE is certainly more convenient for the teac...
by Chris Foley
Tue Feb 18, 2003 3:27 am
Forum: General Discussion
Topic: WANTED: Cheap dot-matrix LEDs
Replies: 11
Views: 2154

Re: WANTED: Cheap dot-matrix LEDs

Sorry - can't help you with 10 of these. There are better deals out there, but you might want to either try Jameco (surplus components that usually work), or if you're really doing the churchmouse thing, buy LEDs by the bushel and build what you want out of discrete LEDs on 10 scraps of perfboard (s...
by Chris Foley
Mon Feb 17, 2003 11:21 am
Forum: General Discussion
Topic: WANTED: Cheap dot-matrix LEDs
Replies: 11
Views: 2154

Re: WANTED: Cheap dot-matrix LEDs

Could you provide more information? Matrix size (e.g. 5X7), color, display height, single- or multi-digit, &c. Also quantity needed. Thanks.
by Chris Foley
Sat Feb 15, 2003 10:38 pm
Forum: General Discussion
Topic: POST FOR CHRIS FOLEY
Replies: 1
Views: 694

Re: POST FOR CHRIS FOLEY

Hi, lex. Sorry to keep you waiting. The MBAs let my boss go, and I'm doing his job as well as my own now. I don't have an available schematic with cascading 4026s, but you might want to look at this data sheet...<p> http://www.megatronics.lk/data/4000/hcf4026.pdf <p>This has another, more legible ap...
by Chris Foley
Wed Feb 05, 2003 9:36 pm
Forum: General Discussion
Topic: transistor bridge
Replies: 13
Views: 2425

Re: transistor bridge

Is it possible we're talking about the venerable CA3046? The part's still around (booted from RCA to several sources, now made by Intersil and refuses to die) and consists of five NPN transistors with a common substrate, two of which are connected as a differential pair. The datasheet's available at...
by Chris Foley
Wed Feb 05, 2003 9:17 pm
Forum: General Discussion
Topic: cd4026 help
Replies: 1
Views: 735

Re: cd4026 help

Hi, Lex. Your description of the problem may show the solution. You said you "connect the second ic clock inhibit pin to the 5 volt source". That will prevent the chip from counting. Try grounding that pin. The datasheet for that IC is available at..<p> http://focus.ti.com/docs/prod/productfolder.jh...
by Chris Foley
Mon Jan 27, 2003 8:24 pm
Forum: General Discussion
Topic: Talking Thermostat
Replies: 4
Views: 1716

Re: Talking Thermostat

Here are a couple of "store-bought" talking thermostats, Max --<p> http://home.interlog.com/~keratech/thermsd2.htm http://www.amer-comfort.com/webapp/GetPage?pid=123 <p>There are a lot of opportunities for experimentation in process heating control, but if I might express a personal opinion, Grandma...
by Chris Foley
Thu Jan 16, 2003 11:17 pm
Forum: General Discussion
Topic: ph sensor?
Replies: 2
Views: 1058

Re: ph sensor?

Information on pH sensors and meters is available at www.omega.com. Also, there is good technical reference material at the Omega Engineering site, at http://www.omega.com/techref/
by Chris Foley
Thu Jan 16, 2003 3:52 am
Forum: General Discussion
Topic: car alarm
Replies: 6
Views: 1739

Re: car alarm

A good place to start learning about touchswitches, and digital logic in general, is CMOS Cookbook by Don Lancaster, which should be available through your library. Mr. Lancaster's web site is [url=http://www.tinaja.com,]www.tinaja.com,[/url] and is worthwhile for any technical student. You can buy ...