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 1381-Cx 1 | voltage detector. 2.0 volts active high 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.
Third, we capacitivly couple the photodetector so that it only passes on pulses of light.
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.
See also:
Questions:
"J. L. Patterson, Will Neon Photo-conductors Replace Relays in Low-Speed Logic?, Electronics, 36:18 p 46-49."+
I have built similar nor gate arrays and routed the light using vinyl cord from the craft store.
Fun stuff!
| file: /Techref/idea/logicblocks.htm, 5KB, , updated: 2011/9/29 16:03, local time: 2012/2/8 16:24,
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 Peter Todd has released source and sample projects for his artwork, including his 3d wireframe cube renderer for the PIC 18f6520 This includes examples of hardware developed with free software tools such as gEDA/gschem/PCB, SDCC, gputils and picp all on Linux. http://petertodd.ca/art/source-code/ |
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