Lidmotor's Penny circuit help needed.

[TinselKoala]

Wow...thanks for the link to that Arduino store. How can they sell stuff for so cheap? It's amazing. I might have to place an order there myself, those "starter packages" have a lot of useful items in them. It looks like you could put together an inductance meter equivalent to the one I showed above for under 25 dollars (the Mega and the 2-line LCD). Those LCDs are not as easy to use as the Parallax one I used, though, I don't think. You need several data lines, whereas the Parallax just uses a single serial data line, so only three wires to deal with and no soldering. But it also cost about 10 times more than the ones your link offers.

I don't understand any of that stuff in your "battery" config menu except for the DC voltage and the tolerance! I was hoping to see items like "internal impedance" or stuff like that. Is there some other choice of DC supply instead of a battery, I wonder? Like "voltage regulated DC" or "constant current (really current-limited) DC supply" or such like?
I mean, an ideal battery will provide whatever current the load will demand without sagging in voltage at all. So if you have a zero resistance short you get infinite current at the rated voltage. Of course real batteries don't behave like this because they act like a voltage source in series with a small resistor, so the max current is limited and the voltage will sag as the limit is approached.

[Dark Alchemist]

Yeah, their prices are Crazy Eddie time (flash back, lol).

See the Paralax is a serial version and these guys sell parallel versions and price versus number of I/O lines required.  On the Mega you have enough lines to do it and have enough left over but on an UNO you would be hurting so most go the 3 line serial route.

I have a Halloween project I might do and that Ping sensor is only a $1.85 delivered.  Insane.

[Dark Alchemist]

BOOM, lookee there.

[TinselKoala]

Wow, there you go. You could probably simulate a depleted battery by raising the internal resistance a hair and lowering the amp-hour capacity. Since the capacity is adjustable I'll bet the model includes a "discharge curve" of terminal voltage vs. percent charge or something like that. You probably can't see this internal curve but by setting the two variables in that screen you will be adjusting it.

So you could compare the behaviour of the system using the non-ideal battery with a bit more internal resistance and a very low A-H capacity, if the sim will allow you to set it that low. Compare the waveforms you get, with those you get using the "DC power supply" which is probably a voltage-regulated supply that won't sag like a battery will.

I've just made another little video showing that the thing oscillates even when the voltage is too low to light the LEDs, and what happens when you make and break the connection to the 1.2 nF cap in that low-voltage condition. Also I use a radio tuned to the frequency range it is making and you can actually hear the frequency sweep as it changes modes.

It will be a few minutes before the upload is done.
http://youtu.be/4tMwntAO_cI

[TinselKoala]

Heh.... I thought I was all done with Joule Theifs for a while. I have them scattered all over the lab, there must be six or eight of them lurking around. But now I've gone and discovered a new (to me anyway) effect using this one.

The tiny button cell I used in the video above seems to be able to work as a heat-to-electricity converter.

I did something that you should never do: I soldered wires directly to the cell. The battery can explode from overheating if it gets too hot... so wear safety glasses and keep the children (and parents) well away. And since I have this isolated soldering station, I work on live circuits..... and so I found that heating up the battery by soldering on it causes it to put out plenty of voltage to light up the LEDs for a few seconds, then they dim out. Apparently this process can be repeated over and over.

I'm so startled by this that I had to record it on video. The vid is a bit longer and it's uploading now but it will be a while before it appears.
http://youtu.be/K7msKzlNzKw