Forums

Ambient Power Module

Started by David White March 15, 2012
I am trying an experiment using the circuit below to power a 3V LCD
digital clock.

http://www.4shared.com/photo/WdTFliAW/Ambient-power.html

The antenna is connected to one of the purlins of my metal garage. The
ground is connected to the 110V wall socket ground pin.

However, the caps charge up MUCH better when I simply hold the ground
wire from the module in my hand, eg. 3 or 4VDC this way as opposed to
less than half a volt.

Is there a reason for this? Is my wall socket ground defective?

David White


David White wrote:
> I am trying an experiment using the circuit below to power a 3V LCD > digital clock. > > http://www.4shared.com/photo/WdTFliAW/Ambient-power.html > > The antenna is connected to one of the purlins of my metal garage. The > ground is connected to the 110V wall socket ground pin. > > However, the caps charge up MUCH better when I simply hold the ground > wire from the module in my hand, eg. 3 or 4VDC this way as opposed to > less than half a volt. > > Is there a reason for this? Is my wall socket ground defective? >
Did you eat chili with lots of jalapenos in there? Just kidding :-) Probably the purlins are grounded via some path and so is the PE of your wall outlet -> not much juice. Whereas your body couples to all sorts of live wires behind drywall. Or maybe to that big radio station down the road. -- Regards, Joerg http://www.analogconsultants.com/
David White wrote:

> I am trying an experiment using the circuit below to power a 3V LCD > digital clock. > > http://www.4shared.com/photo/WdTFliAW/Ambient-power.html > > The antenna is connected to one of the purlins of my metal garage. The > ground is connected to the 110V wall socket ground pin. > > However, the caps charge up MUCH better when I simply hold the ground > wire from the module in my hand, eg. 3 or 4VDC this way as opposed to > less than half a volt. > > Is there a reason for this? Is my wall socket ground defective? > > David White > >
Being metal I would assume it would be grounded? even if you connected to a wooden purling that is supporting a metal roof or wall for example, the metal is still grounded. that Is just an assumption on my part. Jamie
On Thu, 15 Mar 2012 20:51:07 -0500, Jamie
<jamie_ka1lpa_not_valid_after_ka1lpa_@charter.net> wrote:


> Being metal I would assume it would be grounded? even if you connected >to a wooden purling that is supporting a metal roof or wall for example, >the metal is still grounded. >
Good point raised. I will try a vertical wire. David
On 3/15/2012 4:54 PM, David White wrote:
> I am trying an experiment using the circuit below to power a 3V LCD > digital clock. > > http://www.4shared.com/photo/WdTFliAW/Ambient-power.html > > The antenna is connected to one of the purlins of my metal garage. The > ground is connected to the 110V wall socket ground pin. > > However, the caps charge up MUCH better when I simply hold the ground > wire from the module in my hand, eg. 3 or 4VDC this way as opposed to > less than half a volt. > > Is there a reason for this? Is my wall socket ground defective? > > David White > >
Your body is a capacitor with a parallel resistor. In ESD testing, that is 100pf and 1500 ohms as a standard. Now in real life, I could believe 100pf. Probably your resistance to ground is higher than 1500 ohm. So you are breaking the direct leakage path which I assume exists between the metal shelter and ground. But going through your body, I doubt you can get much current. You get 3V, but this is more likely a function of the meter you are using being high impedance. I would venture a guess hat the rain gutter on the house is a better source of an antenna, presuming it doesn't touch the ground. Lots of metal, high in the air, sounds about as good as it can get. Have you considered a crystal radio?
David White wrote:
> I am trying an experiment using the circuit below to power a 3V LCD > digital clock. > > http://www.4shared.com/photo/WdTFliAW/Ambient-power.html > > The antenna is connected to one of the purlins of my metal garage. The > ground is connected to the 110V wall socket ground pin. > > However, the caps charge up MUCH better when I simply hold the ground > wire from the module in my hand, eg. 3 or 4VDC this way as opposed to > less than half a volt. > > Is there a reason for this? Is my wall socket ground defective? > > David White > >
You are tossing a large amount of the signal by using sand power instead of flower power.
"David White"  wrote in message news:4f627fb8.3433125@news.tpg.com.au...


> I am trying an experiment using the circuit below to power a 3V LCD > digital clock.
> http://www.4shared.com/photo/WdTFliAW/Ambient-power.html
[snip] C1 is shown backwards. And you might get better results with Schottky=20 diodes, although leakage may be more of a problem than forward drop. A better antenna might be some chicken wire stretched along some = insulated=20 posts, or maybe a frame made of PVC pipe. Paul=20
On 3/17/2012 12:36 AM, P E Schoen wrote:
> "David White" wrote in message news:4f627fb8.3433125@news.tpg.com.au... > > >> I am trying an experiment using the circuit below to power a 3V LCD >> digital clock. > >> http://www.4shared.com/photo/WdTFliAW/Ambient-power.html > > [snip] > > C1 is shown backwards. And you might get better results with Schottky > diodes, although leakage may be more of a problem than forward drop. > > A better antenna might be some chicken wire stretched along some > insulated posts, or maybe a frame made of PVC pipe. > > Paul
There are always exceptions, but most of us would get better results with a MUCH higher frequency receiver. Local dollar store sells solar yard lamps with the receiver with small built-in antenna (AKA solar cell) rechargeable battery and boost converter that can do 3V....all for a buck. Light is about as ambient as it gets.
On 3/17/2012 12:36 AM, P E Schoen wrote:
> "David White" wrote in message news:4f627fb8.3433125@news.tpg.com.au... > > >> I am trying an experiment using the circuit below to power a 3V LCD >> digital clock. > >> http://www.4shared.com/photo/WdTFliAW/Ambient-power.html > > [snip] > > C1 is shown backwards. And you might get better results with Schottky > diodes, although leakage may be more of a problem than forward drop.
I just stuck a 1N21WE on the curve tracer. Forward voltage is less than a tenth of a volt at currents required to run a clock. Reverse leakage is 10uA at 1.5V. AT 65F. So, if you don't get 'em hot they might be a net win over the silicon diodes. Maybe use pairs in series. NO idea what they cost these days.
> > A better antenna might be some chicken wire stretched along some > insulated posts, or maybe a frame made of PVC pipe. > > Paul
P E Schoen wrote:
> "David White" wrote in message news:4f627fb8.3433125@news.tpg.com.au... > > >> I am trying an experiment using the circuit below to power a 3V LCD >> digital clock. > >> http://www.4shared.com/photo/WdTFliAW/Ambient-power.html > > [snip] > > C1 is shown backwards. And you might get better results with Schottky > diodes, although leakage may be more of a problem than forward drop. > > A better antenna might be some chicken wire stretched along some > insulated posts, or maybe a frame made of PVC pipe. > > Paul
Capacitor polarity is not significant at the low voltages present. Leakage in Schottky or flower power diodes (VERY similar) for all practical purposes is not significant even for DC frequencies like those in the broadcast band.