Search found 326 matches

by kheston
Wed Sep 16, 2009 12:22 pm
Forum: General Discussion
Topic: battery monitoring with opto-isolators
Replies: 50
Views: 6407

Re: battery monitoring with opto-isolators

10k/(10k+30k) = 0.25!

This would work for both 6v and 12v LA batteries with no circuit changes. Nice!

...I don't usually try to over-complicate things.
by kheston
Wed Sep 16, 2009 7:52 am
Forum: General Discussion
Topic: battery monitoring with opto-isolators
Replies: 50
Views: 6407

Re: battery monitoring with opto-isolators

MrAl, Again, you've exposed my ignorance. I thought I couldn't go over Vcc on any pin, including ones I've set up to be ADCs. Are you saying I merely need a current limiting resistor and I can read 0-20v on a pin of my 12F683? If so, that's the ticket! If not, what have I missed? BTW - The extra-cod...
by kheston
Tue Sep 15, 2009 10:22 pm
Forum: General Discussion
Topic: battery monitoring with opto-isolators
Replies: 50
Views: 6407

Re: battery monitoring with opto-isolators

I found this TI app note:

http://focus.ti.com/lit/an/slyt173/slyt173.pdf

that seems to explain things well. I'm Googling for more examples as I write this...
by kheston
Tue Sep 15, 2009 6:00 pm
Forum: General Discussion
Topic: battery monitoring with opto-isolators
Replies: 50
Views: 6407

Re: battery monitoring with opto-isolators

I'm still working on this one as I have time... My PIC 12f683 has 10-bit ADC resolution. I want to measure 9-18v. Right now, I'm using an R1=1M, R2=330K voltage divider. So, 9v = ~2.23v and 18v = ~4.47v. Can I use an op-amp or something to make a 9-18v range look something more like 0-5v to the PIC?...
by kheston
Mon Aug 31, 2009 7:12 pm
Forum: General Discussion
Topic: Hybrid Boat
Replies: 4
Views: 1691

Re: Hybrid Boat

I'm in the process of converting this to charge each of the 12v batteries in my 48v bank: http://www.delanobay.com/DcGenSet/DSC_0018_small.jpg http://www.delanobay.com/DcGenSet/DSC_0021_small.jpg I'm making plastic bushings for the all-thread you see in the pics to separate the grounds. There's a lo...
by kheston
Mon Aug 31, 2009 10:14 am
Forum: General Discussion
Topic: LEDs vs. bulbs
Replies: 25
Views: 3274

Re: LEDs vs. bulbs

Google on ledlightswarehouse and you'll see there's a handful of other forums that have seemingly innocent posts with a link to their site. I'd wager you'll find more posts as the search engines have time to refresh their page caches. Perhaps the OP will log on soon and cry foul, but this REALLY sme...
by kheston
Mon Aug 31, 2009 7:40 am
Forum: General Discussion
Topic: battery monitoring with opto-isolators
Replies: 50
Views: 6407

Re: battery monitoring with opto-isolators

I was reading through the latest issue of Circuit Cellar last night and came upon the LTC6802. It can monitor up to 12 series-connected batteries and can be daisy-chained to monitor even more. Alas, in poking around the Linear site I couldn't find a lead-acid version, only for Li-Ion. Oh well. Back ...
by kheston
Sun Aug 30, 2009 8:08 pm
Forum: General Discussion
Topic: Poor, poor victim of the swine flu
Replies: 11
Views: 1563

Re: Poor, poor victim of the swine flu

Incidentally, I'm not sure how you got 'hold of one of my baby pics MrAl, but I'm gonna tell my mother to be more careful about who she gives them to in the future!
by kheston
Sun Aug 30, 2009 8:07 pm
Forum: General Discussion
Topic: Poor, poor victim of the swine flu
Replies: 11
Views: 1563

Re: Poor, poor victim of the swine flu

Dac, You know that there's no facility to actually upload pics to this forum, right? MrAl has uploaded the photo you see to http://img199.imageshack.us/img199/170/77647687.jpg (another site) and is using the forum command "[img]" to make it visible here. Can you describe what you're doing that isn't...
by kheston
Sat Aug 29, 2009 7:01 pm
Forum: General Discussion
Topic: LEDs vs. bulbs
Replies: 25
Views: 3274

Re: LEDs vs. bulbs

I think we may be replying to a spammer's attempt at creating more referrers to their site.

I'm always suspicious when a new user's first post contains a link to their site.
by kheston
Fri Aug 28, 2009 9:55 pm
Forum: General Discussion
Topic: Robo calls to go illegal, HURRAY! Finally!
Replies: 5
Views: 1074

Re: Robo calls to go illegal, HURRAY! Finally!

I hope it includes political campaigns as well. My green beans don't go well with politics.
by kheston
Wed Aug 19, 2009 7:43 pm
Forum: General Discussion
Topic: Need help on a new project
Replies: 10
Views: 2035

Re: Need help on a new project

Maybe the fish scale is more technically complex than you need at this point. Perhaps a dog-lead tied to the end of a pull spring, wrapped around a pulley with a potentiometer dial as the axle would be an easier prototype to build? I've never built anything around a strain gauge but I'd imagine the ...
by kheston
Tue Aug 18, 2009 4:18 pm
Forum: General Discussion
Topic: Inverter travels
Replies: 3
Views: 880

Re: Inverter travels

I've never been paid (money) to write an article, if that's what you mean. I have been asked to help author written materials here and there, nothing noteworthy, grant and software design proposals, mostly. I'm really glad you enjoyed my post, however. Perhaps it will come in handy some day...
by kheston
Mon Aug 17, 2009 10:20 pm
Forum: General Discussion
Topic: Inverter travels
Replies: 3
Views: 880

Inverter travels

If aren't considering purchasing an inverter and aren't even curious about them, this post may bore you to tears. However, if you are interested in one man's experience with a select few of them, enjoy! Many of you have been kind enough to post guidance for me on DC-to-AC inverters. Some of it has c...
by kheston
Mon Aug 17, 2009 12:07 pm
Forum: General Discussion
Topic: battery monitoring with opto-isolators
Replies: 50
Views: 6407

Re: battery monitoring with opto-isolators

MrAl,

Thanks for the clarification!

I have an 18F4550 and 2 12F683s I can hook up via a 4N35 and play with. Doesn't sound hard at all.