Simple useful circuits

But I can't recommend it due to issues with handling acid & lead sludge. In a totally uncontrolled environment things would go wrong.

No kidding. Most people don't need to be messing with that. :-)

That might be effective for batteries with high internal resistance. I'm thinking the light bulb would create a constant current effect.

I remember now that my brother did a lot of recharging dry cells. IIRC it worked pretty well as long as you kept an eye on the temperature. I did that with calculator, with an LED readout, that ate batteries. I just used the AC wall wart and left the batteries in, Didn't seem to hurt anything.

On Saturday, November 14, 2015 at 6:56:24 PM UTC-5, snipped-for-privacy@gmail.com wrote :

junk. What simple circuits have you found useful? Whether as tools or end products. Have already done minimal versions of audio amp, sig gen, alarm, voltmeters. I've a list of ideas but I'll bet you have some interesting one s I've not thought of.

Re: 3rd world development, there's existing research.

For real projects, see

There is also related technical journals like

Good luck and best wishes, Rich Sulin

On Saturday, November 14, 2015 at 6:56:24 PM UTC-5, snipped-for-privacy@gmail.com wrote :

junk. What simple circuits have you found useful? Whether as tools or end products. Have already done minimal versions of audio amp, sig gen, alarm, voltmeters. I've a list of ideas but I'll bet you have some interesting one s I've not thought of.

Here's a purely electronic device... simple, life-saving -- a fire alarm:

Developing world uses a lot of open flames, so risk of fires is very high.

Rich S

Here's a purely electronic device... simple, life-saving -- a fire alarm:

Developing world uses a lot of open flames, so risk of fires is very high.

Rich S

A CO detector might serve well also.

ic junk. What simple circuits have you found useful? Whether as tools or en d products. Have already done minimal versions of audio amp, sig gen, alarm , voltmeters. I've a list of ideas but I'll bet you have some interesting o nes I've not thought of.

astating-fires/

Fire is a killer at times, and there are typically no firefighting services available. Many settlements are built on huge garbage dumps to benefit fro m scavenging, which is bad news in a fire. Those alarms are nice, but inher ently expensive, and that heavily limits deployment. We've worked on fire a larm designs that cost nothing - lower performance but the ability for peop le to produce them in great quantity is a plus in terms of lives saved. The fire alarm project is currently ongoing.

NT

Cooking fire fumes are a big cause of death. But is there a technology to detect CO that can be made for 10 cents a piece?

NT

ic junk. What simple circuits have you found useful? Whether as tools or en d products. Have already done minimal versions of audio amp, sig gen, alarm , voltmeters. I've a list of ideas but I'll bet you have some interesting o nes I've not thought of.

rs Without Borders). They identify the most basic human needs, which aren't all mainly electronic, but solar power is. Not that electronics can't play a role in any of them.

As well as the direct benefits, electronics brings people money, which tack les the majority of poverty's problems.

ndex.php/jhe/index (Journal of Humanitarian Engineering).

thank you

NT

I read the report on the water purification system. Some interesting observations: The system was not built from junk found by the side of the road. The system was not built by the locals. The system was provided for FREE by externally sourced scientists from top-notch commercially available components. The location was cherry-picked to one with an existing well and infrastructure. Somebody built an appliance that could be operated by the natives with little or no training. The system provided jobs for some of the natives.

Humanitarian projects fully funded by EXTERNAL benevolent organizations are a great way to create spot improvements. The other 4-billion in poverty were not affected, and are not likely to ever be affected by their own efforts.

Water purification means fewer children die from water-borne infection. The other side of that coin is that they contribute the exponential growth of the poverty-stricken population.

We all want to help. Makes us feel good. Dogooders want to equalize the standard of living across the board. Not a problem if you're satisfied with reducing YOUR standard of level to match the have-nots.

There are NOT enough resources to raise half the world out of poverty. You cannot give away stuff to help the down-trodden. You have to give them a skill so that they can produce goods and services that are in demand by people who can afford to buy them and a stable political system that encourages investment.

what did that all cost per person served?

re

Yes, the benefits are very real, they save lives and reduce suffering. The trouble is they can never impact even 0.1% of the problem due to the cost.

Every wealthy country on earth has got there from poverty by their own effo rts. It's how countries have got wealthy.

I think there are better options

What one can do is use resources more efficiently to improve life in povert y - and improve it quite a lot.

Theoretically it's possible with goods we would regard as junk here. But th e will is not there, and the outcome is unknown but unlikely to be great in practice. Looking at one example, when lots of TVs etc were dumped, litera lly, in Africa the outcome was that a handful of people subsisted on it by removing copper for scrap, and the rest all got burnt. So something like 99 % of the value was lost. Taking another example in Peru, young gangs took a nything of value, leaving only things like paper, glass & bottletops. The m oney went to the wrong places.

exactly what I'm doing

That's a problem, but I don't know anyone that has worked out how to solve it.

NT

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detect CO that can be made for 10 cents a piece?

There's a plastic film that darkens (turns orange) when exposed to CO. It's not the most sensitive technique, but may be good enough, especially if it is near the potential source. A simple electronic circuit to detect the ph oto-optic change would be cheap.

A low-battery warning would have to be included too (though, if the battery is the most expensive part, then just discard the whole thing with a fresh unit).

Another issue is that the film could get dusty, dirty, aged (after some amo unt of CO exposures, the film will not return to fully clear) leading to fa lse alarms. So it has to be designed to keep the dust out. The aging may no t be a problem if its replaced after a time and/or after any alarm event.

I do not know if anyone has designed this into a product yet!

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to detect CO that can be made for 10 cents a piece?

's not the most sensitive technique, but may be good enough, especially if it is near the potential source. A simple electronic circuit to detect the photo-optic change would be cheap.

ry is the most expensive part, then just discard the whole thing with a fre sh unit).

mount of CO exposures, the film will not return to fully clear) leading to false alarms. So it has to be designed to keep the dust out. The aging may not be a problem if its replaced after a time and/or after any alarm event.

Google so far shows lots of experiments on films, but nothing buyable.

NT

You might be interested in our patent prototype.