Search found 74 matches

by desterline
Fri Nov 21, 2003 11:31 pm
Forum: General Discussion
Topic: driveway sensor
Replies: 7
Views: 1150

Re: driveway sensor

Light-beam break detector?
by desterline
Thu Nov 13, 2003 7:28 pm
Forum: General Discussion
Topic: Calculators
Replies: 3
Views: 932

Re: Calculators

by desterline
Sun Nov 09, 2003 2:13 pm
Forum: General Discussion
Topic: Lead acid battery
Replies: 11
Views: 3016

Re: Lead acid battery

I can add a note about automotive batteries. Typical car batteries (for starting) are not very tolerant of deep discharging. If you discharge a 12v batt to 6 volts and then recharge it, it will only hold about %60 of its previous capacity. Do this a few times and it adds up. Starting applications ar...
by desterline
Tue Nov 04, 2003 11:03 pm
Forum: Robotics
Topic: robot navigation
Replies: 2
Views: 1581

Re: robot navigation

I've since lost the links, but I have copies of a couple e-papers on optical navigation. If you can't find any other resources, give me an address and I'll e-mail them to you.<p>360 sensors!? Wow, you must have some funding.<p>Curious, why didn't you implement a more conventional "scanning" system. ...
by desterline
Tue Nov 04, 2003 10:45 pm
Forum: General Discussion
Topic: 1.5 volt Solar cell to charge capacitor so it can be use
Replies: 7
Views: 1420

Re: 1.5 volt Solar cell to charge capacitor so it can be use

Watch out with those super caps. They are not the least bit tolerant of overvoltage. <p>A solar cell rated at 3 volts could put out quite a bit higher (5-6 volts not unheard of) in bright light and little load. That's enough to damage a supercap, even through a blocking diode.<p>While a solar cell p...
by desterline
Tue Nov 04, 2003 3:20 pm
Forum: General Discussion
Topic: RC reciever Help
Replies: 4
Views: 998

Re: RC reciever Help

Search the web for 'H-bridge'<p>You should find pleanty of schematics on how to hook up a two transistor 'totem pole' output stage (more correctly called a 'half-bridge') <p>It can be done with regular bipolar transistors or FETs. That should get you into the 2-5 amp range without any major problems...
by desterline
Tue Nov 04, 2003 3:14 pm
Forum: Computer Programming
Topic: Programming on a typical computer
Replies: 8
Views: 3402

Re: Programming on a typical computer

Then there's always VBA (visual basic for applications)<p>Of course it will reside in a MS Office document, but VBA is a very complete language with most all the 'frills' of other languages. And nothing to install (asuming you have some version of at least one MS office product) <p>-Denny
by desterline
Wed Oct 29, 2003 1:06 am
Forum: General Discussion
Topic: FIRE FLYS
Replies: 26
Views: 4039

Re: FIRE FLYS

This might be more hardware than you want, but why not just hook up a five 555 circuits? <p>Since they would all have differnt frequencies, they would blink randomly. Any other method is going to produce some kind of pattern. <p>-Denny
by desterline
Fri Oct 24, 2003 7:04 am
Forum: General Discussion
Topic: stable clock timer..for a different LED clock
Replies: 18
Views: 3140

Re: stable clock timer..for a different LED clock

All those alternatives are plausable. I was just tossing out the simplest one I could think of.<p>The zener diode design is better as it provides a safety against high voltages into your logic, and of course reverse voltages. But square-er pulses realy isn't a problem if the signal is run through a ...
by desterline
Fri Oct 24, 2003 6:54 am
Forum: General Discussion
Topic: Schematic Software
Replies: 6
Views: 1304

Re: Schematic Software

I like the freeware version of Eagle
www.cadsoft.de <p>The schematic tools integrate nicely with the PCB layout tools.<p>The free version is limmited to one-page schematics (not a serious limitation for the hobbiest) and a certain size for the PCB. (also not to bad for the hobbiest)<p>Denny
by desterline
Thu Oct 23, 2003 4:50 pm
Forum: General Discussion
Topic: RPM regulation
Replies: 55
Views: 9022

Re: RPM regulation

Not that this is the best idea, ok maybe it's not even a good idea, but before I hooked up a vane in the windstream, I'd think about an solenoid balanced against a spring.<p>RPMs go up - voltage goes up - solenoid is retracted, closing throttle.<p>Like I said, probably not even a good idea.<p>-Bette...
by desterline
Thu Oct 23, 2003 4:41 pm
Forum: General Discussion
Topic: Kill switch light
Replies: 14
Views: 2122

Re: Kill switch light

I was thinking double pole (rather than double throw) but I can imagine either working out ok.<p>As to batteries, -with alkilines- AAAs have about 600mAh, AAs have about 2500mAh, Cs about 6000mAh, and Ds are above 18000 mAh, typical 9V are only 300 -500mAh. <p>Granted these a rough numbers with a lo...
by desterline
Thu Oct 23, 2003 4:31 pm
Forum: General Discussion
Topic: stable clock timer..for a different LED clock
Replies: 18
Views: 3140

Re: stable clock timer..for a different LED clock

I don't have a schematic handy, but it's not complicated so I'll try and describe it.<p>Basicaly you need to connect to the secondary (low voltage) side of your power transformer with a single diode. That will provide you with a 1/120 sec pulse every 1/60 of a sec - half wave rectification.<p>Then t...
by desterline
Wed Oct 22, 2003 7:43 pm
Forum: General Discussion
Topic: Kill switch light
Replies: 14
Views: 2122

Re: Kill switch light

I'd be thinking the AAs. What kind of switch is it? My thinking is that some of the older chainsaws I've been around had a typical toggle switch. If you could replace it with a double pole one, the circuit becomes ultra simple.<p>Any possibility of that?<p>-Denny
by desterline
Wed Oct 22, 2003 7:38 pm
Forum: Robotics
Topic: Gearhead motors
Replies: 9
Views: 3061

Re: Gearhead motors

Black an decker makes a cordless screwdriver that uses 4 AA batteries (6 volts) - rated at 130 rpm. (about $8 at home despot)<p>They run a little fast on 12 volts, but you shouldn't burn them unless they're stalled for a long time.<p>[ October 22, 2003: Message edited by: desterline ]</p>