Search found 16 matches

by Calcbert
Mon Feb 23, 2004 9:10 pm
Forum: General Discussion
Topic: help with x-10
Replies: 5
Views: 1190

Re: help with x-10

You should look into the PL513 and TW523 modules if you haven't already. They're pre-made circutis for doing the X-10 interfacing, but I doubt it's real easy to couple signals onto the power lines yourself.<p>You'll probably need a microcontroller or a good deal of logic & timing circuitry to interf...
by Calcbert
Sun Feb 15, 2004 8:19 pm
Forum: General Discussion
Topic: Vdd and Vss meaning?
Replies: 3
Views: 1006

Re: Vdd and Vss meaning?

Also very commonly representative of the +5V supply voltage to a circuit (Vdd) and Ground (Vss).
by Calcbert
Fri Sep 19, 2003 10:33 pm
Forum: General Discussion
Topic: Scanner Chip?
Replies: 3
Views: 817

Re: Scanner Chip?

Can't be sure, but I'd definitely bet it's something like an EPROM programmed with a custom piece of software for that scanner. Unless you have the same scanner with that chip missing, it's probably useless to you.
by Calcbert
Mon Sep 08, 2003 8:28 pm
Forum: General Discussion
Topic: detect resistance changes
Replies: 3
Views: 944

Re: detect resistance changes

I'll assume for now that you're using a thermistor (resistor that varies quite precisely with temperature).<p>There's two options that I could see. Using an Analog to Digital conversion like Russ Kincaid recommended is one good way if your microprocessor has that capability already. Connect the ther...
by Calcbert
Sun Sep 07, 2003 9:23 pm
Forum: General Discussion
Topic: LED fading when driven by 4017
Replies: 8
Views: 1826

Re: LED fading when driven by 4017

Something I worked on a little bit at one time...I can't guarantee how well it will work, but it might be worth a try.<p>Use a combination of an NPN transistor (i.e. 2N2222, 2N3904), a capacitor, and a resistor. Use something like a 10 or 100uF capacitor and perhaps 470 or 1K ohm resistor (it's very...
by Calcbert
Wed Jul 23, 2003 8:13 pm
Forum: General Discussion
Topic: Overhead Door Opener Controller Question
Replies: 3
Views: 1538

Re: Overhead Door Opener Controller Question

When I took apart an old Sears opener, there was an opto-interruptor set up for the motor shaft. (Opto-interruptor = LED shining on phototransistor, with something blocking it once in a while.) I suspect this was expected to be interrupted at a known rate to indicate that the motor had not stalled. ...
by Calcbert
Wed Jul 23, 2003 8:00 pm
Forum: General Discussion
Topic: Bike spedometer
Replies: 10
Views: 1883

Re: Bike spedometer

Well initially I'd say "go get a speedometer from a bike shop" and save some time. But that's not the tinkerer's way to do it.<p>Commercial speedometers for bikes generally use a magnet mounted on a spoke, and a reed switch mounted on the fork. You're probably best off using a microcontroller. I wou...
by Calcbert
Sat Jul 12, 2003 8:50 pm
Forum: General Discussion
Topic: RF remote signaling
Replies: 9
Views: 2304

Re: RF remote signaling

OK, I missed the part about the 1000 foot range. Most doorbell sets have DIP/jumper settable codes to avoid interference. You could make relay stations perhaps?
by Calcbert
Sat Jul 12, 2003 8:48 pm
Forum: General Discussion
Topic: RF remote signaling
Replies: 9
Views: 2304

Re: RF remote signaling

One more easy idea, about 30 seconds later. I've had great success in modifying cheap wireless doorbell sets to do my bidding. I've operated one for a while as a remote control SLR camera trigger. My Nikon N-70 uses an electrical bulb-type control, and you definitely don't need to buy the official S...
by Calcbert
Sat Jul 12, 2003 8:41 pm
Forum: General Discussion
Topic: RF remote signaling
Replies: 9
Views: 2304

Re: RF remote signaling

You might want to look into these RF modules from Laipac. They seem to be a lot like how garage door openers work, where you'd have a dip switch to set a unique code. I haven't actually worked with them, though I want to. They don't seem to have any distributors, but they do sound willing to ship to...
by Calcbert
Wed Jul 02, 2003 6:31 pm
Forum: General Discussion
Topic: Older parts - need info
Replies: 8
Views: 1968

Re: Older parts - need info

Don't forget to try www.chipdocs.org. You have to pay to get datasheets from them, but they will list the basic description of the chip for free.
by Calcbert
Thu Jun 26, 2003 6:54 am
Forum: General Discussion
Topic: Question on a simple project
Replies: 1
Views: 858

Re: Question on a simple project

The most likely culprit to your problem is the voltage drop across the extra diodes you're adding. Red LEDs need roughly 1.7 V across them to light, and diodes like the 1N914 or 1N4001 need 0.7 V before they begin conducting in any sizable quantity. <p>When you use a resistor in series with the LED,...
by Calcbert
Sun Jun 22, 2003 9:16 pm
Forum: General Discussion
Topic: c547b = to-92/2n3906 ??
Replies: 3
Views: 1273

Re: c547b = to-92/2n3906 ??

Make sure to check myke.com for the latest revisions to the "Book" version of the El Cheapo programmer. A few resistors and capacitors have been taken out, and a clarification is made about the orientation of some of the transistor packages.<p>I had mine built per the specs in the book I got the PCB...
by Calcbert
Sun Jun 08, 2003 10:35 pm
Forum: General Discussion
Topic: Wall warts
Replies: 10
Views: 2634

Re: Wall warts

From my informal understanding, dryers don't so much detect a drop in the moisture of the exhaust as they detect a sharp rise in the air temperature, indicating that the majority of the water has been taken from the clothes. This would also seem to overcome the possibility that the ambient humidity ...
by Calcbert
Sun Jun 01, 2003 10:16 pm
Forum: General Discussion
Topic: Laipac Easy Link Wireless Suppliers
Replies: 0
Views: 614

Laipac Easy Link Wireless Suppliers

Does anyone know of a good supplier of Laipac Easy Link Wireless modules? The modules I'm looking for are the TLP/RLP 315, 418, or 434 MHz modules. Alternatively, do you know of similar modules from another manufacturer?<p>Thank you.