Before beginning, first study all of the posted assembly pictures and diagrams and read through these instructions. Once you are sure what is involved, and you have all the parts ready to go:
There are pictures at the bottom of the page that may help. Once I have built a couple of these, I may have some additional thoughts, pictures or ideas to pass along. As I write this, I have yet to start my own units. My sincere thanks to Rick, K1DS for supplying nearly all of the information on this laser project.
LASER TRANSMITTER ASSEMBLY:
- tin about 12" of two-wire lead and solder the ends to the solar cell
- one wire to the face ribbon wire, the other to the rear of the cell
- be very careful the solar cells are brittle
- mount the solar cell in a foam board sandwich which has been cut from one of the squares, blue side facing out
- tape the sandwich and solar cell together
- drill a small hole in the rear edge of the 4" PVC cap, pass the end of the solar-cell wire through
- force fit foam-disc solar cell into the cap, blue-side out
- solder the 1/8" audio plug onto the other end of the wire
- open the rear of the audio amp and insert the 9V battery
- place one side of the Velcro fastener on the upper rear of the audio amp, the other on the non-solar cell side rear of the PVC cap position the audio amp base so it will be on a flat surface & the PVC cap will not interfere when trying to stand it upright
- you can fit the PVC tube ("antenna") into the PVC cap
- set the receive assembly aside for now
CONTROL CIRCUIT IN A HOBBY BOX:
- study and understand the parts layout
- assemble the circuit board by soldering the IC socket onto the center - make sure the pins extend through the side
- solder the pins to the copper lands on the vector board (bend them over to hold in place if the are no copper lands on your board)
- solder the other 4 components in place
- solder the battery leads as indicated (red positive, black negative)
- drill two holes in your box, one for the RCA connector, the other the push button switch
- mount the switch and the push button switch
- strip the ends of two 4" lengths of the twin wire
- connect & solder one end to the board and the other to the RCA socket
- solder the push button switch to the board with another short length of twin wire
- slide the circuit board into the hobby box
- attach the battery to the clip
- apply the double-sided foam tape to the battery and tape in place in the rear of the box
- install the 55 timer IC
- prior to closing the box, test the assembly for proper operation
- you can: use a known working laser penlight assembly connected to the output leads
- <OR>
- use a digital voltmeter to test for output voltage when the push button switch is depressed
- when you are sure everything is working, close the box
- be very careful not to strip the screw holes in the box
MODIFYING THE LASER PENLIGHT:
- open the laser penlight by unscrewing the end cap
- remove any pill batteries
- any extra lens that came with your penlight are surplus to this project
- drill a small hole in each side of the penlight tube approximately ½" from the rear
- using a small sheet-metal screw, attach the solder lug; do not over-tighten
- prepare a 3 foot long piece of twin wire with an RCA plug on one end
- connect the wire from the center of the RCA jack ground lug/case
- the outer lead gets soldered to the spring of the laser assembly
- tin the wire as a small hook, fish it into the tube through the second drilled hole &hook to the spring, and solder
- screw the back cover onto the penlight
- the RCA plug goes into the transmitter assembly in the hobby box
- push both the laser penlight button and the transmitter push button to check that the transmitter works
- if everything works, use a piece of tape to keep the laser switch in the closed position
- use the shrink tubing over the assembly to hold the tape in place
MOUNTING THE COMPETE ASSEMBLY:
- drill small holes with a 1/16" drill bit in both the 18" aluminum rail and the 1.5" azimuth adjuster
- tap two of the holes with a 4-40 tap hole in the 18" aluminum angle rail and the 1.5" azimuth adjuster piece
- with a round head wood screw & a plastic washer attach the non-threaded end of the rail to the rear of the wooden base
- the base can be 20-24" X 2-3" piece of ¾" plywood, or a 20-24" length of 2x4 or 1x4
- screw the azimuth adjuster with the vertical side facing the vertical side of the long rail - sort of "back-to-back"
- see the photos for additional information and clarification
- thread the 4-40 screws into the appropriate holes
- tape clamp, or rubber band the laser pointer, LED end forward to the rail near the elevation adjuster screw
- using a rubber band adjust tension
- attach the rail to the azimuth angle
- the azimuth screw will now be able to push the rail away
- to keep the assembly steady find a way to mount the board on a tripod or solid surface
- experiment with the az-el adjustment
- once in the field this adjustment will allow an approximate 0.5 meter beam movement over a 1 KM path per revolution
- use the push-button to key the 800 Hz audio modulation for the laser
- the receiver should be kept mounted separately from the transmitter for ease of movement and "antenna steering"
- you may want to devise a way to mount it also
- the easiest way would be to use a plastic or metal strap to fasten it to another piece of wood
UPGRADES THAT MAY MAKE THINGS EASIER:
- add an LED in series with a 330 ohm resistor to the audio amp to indicate power on
- forgetting it is on will drain the battery
- drill a small hole to force fit the LED through top of case & wire in series with the 330 ohm resistor
- be aware of LED polarity, if it does not light you have it backwards
- the transmitter is always off until keyed
NOW YOU CAN LOG EVERY QSO ON YOUR NEW BAND; 440 THz!
