simply RED
April 29th, 2003, 07:29 PM
As i found laser pointers 1,5 dolars per piece i bought 4 and thought what to do with all.
Today I finished a laser pointer transmitter.
The transmitter is a laser pointer connected to a tranzistor (T)(collector of the T to the pointer, the other polus of the pointer to the + (npn). A trimer resistor is connected to the base of the T to the collector (negative back connection). The modulating signal is put on the base with capacitor. (the pointer uses 40 mA so be careful with the choice of the transistor, i used 2T6551 which is no very good).
The reciever input is another transistor connected to fotoresistor (base of the npn,,,, + ).
After this transistor amplifier is put.
The first try was to transmit music. The choice was nightwish, from 200-300 meters at night(at the day you can'y focus the spot on the reciever), perfect sound.
The second was to turn the sceme to remote, using analog coding with one frequency and reciever with the same "decoder" it worked well. Using digital code will make it a safe "toy" for night blasting from 200 -300 meters.
Making good pre amplifier for the reciever with 4 transstors insures that it will work before the red point flashes on the fotoresistor itself.
Today I finished a laser pointer transmitter.
The transmitter is a laser pointer connected to a tranzistor (T)(collector of the T to the pointer, the other polus of the pointer to the + (npn). A trimer resistor is connected to the base of the T to the collector (negative back connection). The modulating signal is put on the base with capacitor. (the pointer uses 40 mA so be careful with the choice of the transistor, i used 2T6551 which is no very good).
The reciever input is another transistor connected to fotoresistor (base of the npn,,,, + ).
After this transistor amplifier is put.
The first try was to transmit music. The choice was nightwish, from 200-300 meters at night(at the day you can'y focus the spot on the reciever), perfect sound.
The second was to turn the sceme to remote, using analog coding with one frequency and reciever with the same "decoder" it worked well. Using digital code will make it a safe "toy" for night blasting from 200 -300 meters.
Making good pre amplifier for the reciever with 4 transstors insures that it will work before the red point flashes on the fotoresistor itself.