Lego Logic Blocks / Optical NAND

Solar or inductivly powered, light pulse activated, artifical neurons in a Lego block

Little blocks with an input end and and output end. When you cover the input, the output flashes rapidly. When light strikes the input, the output is suppressed. If you place two outputs up against one input:

Then you have made a two input NAND. Which is the basic building block of all logic circuits.

AND:

You can SEE the logic levels at each chip
It won't react to ambient light levels since only pulses of light affect it.
Inputs can come from anything that interrupts the beam of pulses from a logic brick with its input plugged. Flags or mirrors can be attached to motor shafts, button, levers, bumpers, etc..
Rather than a solid on / off, they could be set to react more strongly to a stronger signal. There are some interesting "analog logic" possibilities.

Starting with the SolarBotics.com BEAM Photovore Photopopper kit:
http://downloads.solarbotics.com/PDF/kit2.pdf

2N3904 ¹	Standard NPN Transistor	TO-92
2N3906 ¹	Standard PNP Transistor	TO-92
Panasonic 1381x ¹	voltage detector. Versions trip at 2.0 to 4.6 volts	TO-92 or "Mini" SM (2.9mm²
Siemens SFH 205f ¹	Wide Field of View Infrared Photodiode Detector

First, we reduce the size of the PV panel or convert to an induction coil and rectifier for power.

Second, we replace the Motor with an LED.

Finally, the circuit gets compressed to SMT levels and shoved into a lego brick with the photodiode at one end and the LED at the other.

When the photodiode is activated by pulses of light from another source, the LED will be suppressed and will not flash. Increasing the .22uF cap may help to smooth out incomming pulses and prevent triggering between flashes. In general, there will be some frequency at which the input will appear constant to the circuit and will suppress the "neuron"

When enough charge has accumulated from the solar panel or other power source, if the input is not suppressing the circuit, the output will fire a pulse. The 2N3906 is included to keep the 2N3904 on until all the available power is used, and by removing this circuit, we may be able to get a series of flashes rather than one long burst.

file: /techref/idea/logicblocks.htm, 4KB, , updated: 2007/12/18 19:51, local time: 2008/9/5 01:31,

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