PAGER VIBRATOR RAMP UP CIRCUIT

Success! After maybe 5-6 different tries, I have a circuit that works the way I wanted it to!

This is a big achievement for me, as this is the first time had an idea of what I wanted to do first, then successfully designed a series of electronic components that would make it do it correctly! Up to this point, I was either following circuit drawings, or mimicking other circuits, like the solar engines.

This also taught me some more details about capacitors. I already knew how to trickle charge a large Cap up in voltage slowly, either with a trickle coming from a solar cell, or through a high ohm resistor... BUT I never had any practical idea of how to USE that, other than to voltage trigger it to dump it through a motor... making the cap merely a second hand battery.

Now, I know how to make it a timer as well! This is an RC style electronics trick, which most electronics guys would already know about, but I learned it the hard way... as RC to me meant "Radio Controlled" :)

Anyway, here's the circuit, drawn on an index card and definitely going into my "don't forget this trick!" index card box.

So, it took me a few tries; The Cap here, the Cap there, across the motor leads, etc etc.. and it never worked. The Cap wouldn't charge up if there was a motor there to hog all the power, apparently. So, I eventually tried an NPN Transistor between the Cap and motor, hoping that the Base wouldn't "hog" the power from the Cap, and that Base, as it rose in voltage along with the capacitor, would "throttle" the power waiting at the transistor Collector (not sure on the terms yet). Turns out, that was the trick! The capacitor was now "separated" from the motor, the motor getting its power from the transistor. Simple. Sorta. The transistor seemed to peter out with the motor around 5v, and there was 9v there.. so maybe I had reached the limit of what that tiny transistor could "throttle".

SO... hearing about this trick called a "darlington transistor pair", where you simply double up the transistors to get them to supply more working power. THAT was the final problem solved!

 

So, right now that resistor is 1k ohm.. and the ramp up of the pager motor is pretty quick... oh, wait, I didn't show the video of that yet!



Heh.. you cant see it, but the soldering iron resting in those mechanical fingers was vibrated almost out of its holder! Wow that vibrator is strong (when forced with much more power than it was ever designed to take.. hehe). Its out of focus, but I got the gauge in the background showing the voltage rising in the capacitor... It peters out around 7v.. meaning the other 2 is probably what the transistor pair is "stealing" but anyway, it perfectly meets the power requirements to energize the 5v relay after a few seconds delay-  that I plan on adding to my LeaveMeAlone box to give it more "activity"

As I was saying, the resistor causing the delay is 1k Ohm, which is a little too fast I think, but when I tried a 10k ohm, it took too long. So I'm guessing 5k Ohm or so will let the box sit inert for maybe 3 seconds before the first rumblings... then its On like Donkey Kong!! as they say... at least as those as old as I am used to say. heh.

So that's it for today. learning stuff. taking notes. almost vibrating a hot soldering iron into my lap. The usual.