Is this scheme reasonable?

Sure! Use a Cortex M4 and the OP can have a trash can that has to be rebooted periodically!

O tempora! O mores!

Cheers

Phil Hobbs

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Dr Philip C D Hobbs 
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Phil Hobbs
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It's magic, or a decimal point slipped 2 places. 1/2 watt I might believe.

Damn good caps for what I'm doing with them though...

Reply to
default

So what specific suggestion do you have, oh master of practicality?

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Reply to
Tim Wescott

Really? You can't think of any board which could be bought to do this? Or a prototype can be made by any of many choices which don't require a PCB to be made. Do you really need a tutorial?

This is a one off and a fairly simple circuit. Not something that requires a custom PCB really.

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Rick C
Reply to
rickman

Well, if it's so damned easy, provide the tutorial just to spite me! It'll help Eric, which is _my_ goal.

Part numbers! Ebay links! C'mon -- you yourself say it's a snap!

What does it mean to say "oh that's easy, stupid!" and then refuse to demonstrate?

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Reply to
Tim Wescott

Why are you so upset? You said it required making a PCB and I said it doesn't. Now I have to go out and build the damn thing to prove my point? You are a trip.

At this point you are just trolling.

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Rick C
Reply to
rickman

I'm not upset. I'm amused.

But it's really time to put your money where your mouth is, dude, and show how you can do this. Because -- by your own words it's not hard. And it'll benefit _everyone_.

Just a block diagram of a charger that's more intelligent than a wall- wart and a resistor (because that's what a trickle charger is). Or a product he can buy that'll do it. That's all -- no need to show us how to implement it sans PCB.

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Reply to
Tim Wescott

Get me the trash can.

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Rick C
Reply to
rickman

50F x 2.7v = 135C = 135As = 135/3600Ah = 0.0374Ah

50.625Wh /.0375Ah = 1350v

Point slipped 3 places, I think. .05625Wh

Reply to
Bob Engelhardt

Oops ... .50625 ... there's your 1/2Wh "default"

Reply to
Bob Engelhardt

I think you had it right at .05 Watt Hours

Reply to
default

more like 3 decimal places, 0.5*C*V*V/3600

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Reply to
Jasen Betts

I agree. Did the math and posted as much on 5/14.

I'm thinking they mistakenly used some "one size fits all" or watt-hours per X farads.

In a related experiment... I'm temporarily using some Maxwell "D-cell" series caps to power the buoy flasher that got 6 months of use from

3-AA alkaline cells, switching to a solar charged, 175 F, 3 V system (using caps that cost $15 each). That system is flashing the strobe, for 8 days on the charge it can get in one day. (cover the solar cells with aluminum foil and wait till it dies).

So a pair of the $1.29 50 F caps should easily last a day, or perhaps just use one 50 F and go with 2.5V. (specs on the controller that I'm using says it works down to 2.2V, and it seems to recover and start running it's program from the beginning when the voltage gets to about

2V)

The buoy that I'm illuminating belongs to the city.. So I have to keep the cost low in case they discover that I've modified the buoy and decide to remove my strobe, or vandals (or Visigoths) make it to that end of the lake and steal or destroy it...

It's become a "thing" to tweak the buoy with something different each year. I go kayaking at 3:30 AM to avoid the summer heat, but it's a challenge to find ways to see where I'm going in the dark on a lake that's 2 miles long.

Radio beacon? or perhaps a super strobe that I can trigger from 2 miles away?

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default

Tritium light?

Strontium aluminate paint?

Both would be fairly short range visibility. For longer range, why not use GPS?

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John Larkin         Highland Technology, Inc 

lunatic fringe electronics
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Reply to
John Larkin

Tried that too. Got a Magellan "waterproof" little hand-held thingee. Cost a small fortune and wasn't waterproof enough to take dunking in water. Since they stopped the extended warranty plan, I stopped taking it kayaking. It was hard to read too...

The nice thing about it was when I was on a new creek, I could see my progress.

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default

Nah, go for a 2-stroke gasoline-powered trash can :D

I wonder if this could work.

formatting link

Michael

Reply to
mrdarrett

They are rated as waterproof, but not very waterproof. I've yet to find one that will survive on the deck of a kayak for more than a season. Sooner or later they leak and crap out.

I've never had any trouble seeing where I'm going. Even starlight is enough to navigate. Once the stars are gone you have to know your terrain (aquaine?) pretty well though. Overcast makes for interesting trips though. I take you paddle where there is no illumination from houses and such? Even a single porch light in the distance can provide orientation.

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Rick C
Reply to
rickman

There are some cool cmos-sensor night vision cams around these days, not expensive. We use one to film wildlife in the back yard at night, skunks and cats and raccoons and things. But they are not as sensitive as a real microchannel multiplier, and mostly not waterpoof.

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John Larkin         Highland Technology, Inc 

lunatic fringe electronics
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Reply to
John Larkin

I'd love to have a small light waterproof camera to attach to my kite when kite-yaking. Daylight is good enough for that, I only used the kite twice in the dark and hundreds of times in daylight. Small and lightweight are easy enough but waterproof is a whole 'nother thing.

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default

Most days (nearly every day) I paddle to the end of the lake and turn around and come back. There are two large bays jutting off the main lake and one is nearly as long as the main lake. Add a little fog (there have been times where I had no idea where I was) and navigation gets interesting. The houses at the end of the lake make spotting the buoy difficult for their lights and glare.

It's nice to be able to make a beeline for the buoy, then I'm sure I cover the same amount of ground each time, and can time my runs.

It isn't a matter of life or death, or even important that I see the buoy. But I got interested in how to best find it in the dark, and that's evolved into a fun excuse to tinker with electronics.

Then there's the alligators... It's a big lake and there can only be

4-5 gators in it, but on three occasions I managed to surprise sleeping gators - against all odds I would think. There's nothing quite like paddling into a sleeping gator to get one's adrenaline up. And I may know I'm not part of his food chain, but does he know? And those things are so near-sighted they just might take me for another gator impinging on his territory or mate.
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