HandCrank FlashLight

I wonder how this little handcrank flashlight works. They say its cheap and simply made. Sure enough we have the idea on how it works, but inside that plastic case we don't really know how it ticks.

This little wonder sealed by the plastic case. Picture taken on each sides.

Took it apart, picture in opposite sides with main parts showing the crank, gear, light assembly.

Top left, coil winding, top right showing the lamp assembly composed of 2 led's, 3.6V nimh,

 bottom right is the magnet and gear reatio.

My Cassette Radio To Iphone Conversion

Here is an old Radio Shack cassette tape recorder that has been lying around my house. 

 The back information says it uses a six "C" cell batteries.

 

 

 Exposing the circuit.

 

 I removed the unwanted cassette mchanism.

 

 I then soldered the speaker cable to a low impedance circuit. 

 Using the touch method, locate the input circuit. This should be somewhere near the cassette head connector. When touched, it should not create a loud humming sound than the rest of the circuit. You can series a capacitor to be safe.

 Short together the main power and the motor power.

 

 Add an on/off power switch.

Just like the simple toggle switch above which I super glued from the inside.

 

And presto! There goes my Iphone radio.

 

Pedal Exerciser Generator

After building the mini pedal exerciser, I decided to go further. I added a motor to act as a generator to charge my batteries. Stepper motors can be found almost anywhere, specially in printers. Cut a 10 inch diameter wood, added a rubber shaft to the servo motor, reconfigured the wirings, and attached to the exerciser.

 





 Putting the generator into operation. Recharging the 12 volts nickel cadmium batteries. The more you pedal the more you sweat, and the more output you give off to your batteries.

 

 Different looks of stepper motors.

 

Diagram of the 6 pole motor with added 4 each 1N4004 diodes and 1000uf capacitor

Solar LED Garden Light Exposed

This is by far the simplest and the cheapest solar garden light I encountered courtesy of 99Cents Store nearby. Components are cheaply made. The amorphous solar cell measures only 1 3/16in X 1 3/16in. Even the 1.2 volt metal hydride battery is tiny button cell type 40mA.
 

 

 



I was able to cracked and redraw the schematic diagram. The circuit is simple enough which composed of the main ic chip, inductor, battery, solar cell, LED and on off switch. It seemed like it uses one of those ASIC chip, not familiar with the number etched on it. This chip is acting like a pulser multiplier. I measured that the LED is giving off approximately 3mA at frequency of 460 khz. Adding another battery equal ~2.6 volts, the LED went on its brightest and current jumped to 36mA.

 

 

Below is another cheap solar LED light selling in a decorative Halloween look. New item from 99 Cents Store. The ic chip type is different and the white LED consumes 1.3 mA. A little larger solar cell at 1 7/16in X 17/16in.