Prepare the components for surface-mounting by first cutting the leads to the right length. Bending the ends as shown makes for better joints.

A clock before treatment. Open the case using a screwdriver. Push it from the front between the snaplocks. The bending of the clear plastic outwards should be kept to a minimum; push the black plastic hook inwards instead.
	Even before lifting the lid you can clearly see the construction. Open the clock in this attitude, because...
...The gear for setting the clock is secured, but once the lid is off, only gravity is keeping the other parts in position.
	Remove the first gear and the gear/shaft of the seconds hand.
Take the stepping motor plus subframe and PCB out of the case; they form a single part. Cut the copper foil between the chip (black lump) and the right coil contact using a small dentist's drill or a sharp knife. Solder two thin isolated wires (about 5 inches long) onto the coil contacts. Be careful not to disconnect the coil wires. There is no need to use different colors: the coil has no plus or minus side, the direction in which the stepping motor rotates is mechanically determined. Next to the subframe you see the gear of the hour hand, in its original form and with its shaft shortened. Cut off 5 mm, using a sharp knife. Now when you put the clock back together, only the shaft of the minute hand will visibly protrude from the case, so you can securely attach the robot's wheels.
	The case with the hour hand gear back in place. Next to it you see the minute hand gear, the wheel driving the hour hand, and the two battery contacts. All but the minute hand gear can be deligated to the bitbox. The robot doesn't need them.
Drill a 3 mm (0.12") hole in the clear plastic lid, for passing the wires. The hole should be near the coil. Put the clock back together. Check its mechanical operation, by temporarily attaching the seconds hand and turning it carefully. Saw off the battery compartment using a metal saw. The photo shows the final result. Only the minute hand shaft visibly protrudes from the case.

Mechanical assembly and adjustment

A look at the underside of the Photovore. Both clocks have a sprung support attached. The material is the same as used for the feelers: tinned copper wire 0,4 qmm (0.7 mm thick, 21 AWG). First use clear contact adhesive to glue the supports into folded pieces of paper, then glue the paper onto the clocks. Feeler S0 - here in view - should be bent in such a way that it doesn't touch the copper along the edge of the print. Click on the photo for a larger version (76K).

1. The PCB has mounting points for the feelers (marked S0 and S+ on the layout), their contacts (A) and the wires to the clocks (M1, 0, M1) and the solar panel (Z+ and Z0).
   
2. Temporarily connect the clocks and the solar panel (make sure the panel's plus is connected to Z+, the minus going to Z0) and push the seconds hands onto their shafts. Adjust their rotation speed using the 5M variable resistor. Look for the highest rpm where the motors still run smoothly and positively turn clockwise. Make sure you are OK at both the high and the low voltage permitted by the power supply.
3. Vary the voltage over the 4700uF capacitor by partly covering the solar panel (close to a window for good daylight). Adjust the switch-off level using the 250K variable resistor. The clocks should still be running well at that voltage. Just a little lower and the seconds hands will only wobble a bit. Check the rotation speed adjustment.
4. Check the operation of eyes and feelers, by varying the light and connecting point A with S0 or S+.
5. Does everything work really well? Then disconnect the solar panel and use a clear contact adhesive to glue the clocks onto the PCB as shown. Cut their wires to fit and solder them onto the points M1, M2 and the common 0 in between. Make sure M1 and M2 are connected to the right clocks.
6. Take a piece of paper and draw a circle with a radius of 5 inches. Use a pencil or something like that as a former to wind the spring of a feeler. The material is tinned copper wire (0.4 qmm, 0.7 mm thick, 21 AWG). Bend the feeler itself to match a quarter of the circle. Make sure the shaft (at the other end of the spring) is bent in such a way as to put the spring near the corner of the PCB, when the shaft is soldered in place.
7. When both feelers have the correct shape, you can solder them onto the print (points S0 and S+).
8. Bend the contacts in shape and solder them onto the points A.
9. Form the sprung supports to look like the one visible in the first picture. First use clear contact adhesive to glue the supports into folded pieces of paper, then glue the paper onto the clocks.
10. Slide some tight-fitting heat-shrinkable tubing onto the minute hand shafts of the clocks (enough to cover them completely). Then push the wheels on the shafts.
11. Solder two short lenghts of isolated copper wire - different colors to mark plus and minus - onto the solar panel. The connection pads (underside) look pretty solid, but I applied the soldering iron for the shortest possible time! Use just a little solder and make sure it flows. One second is enough.
12. Stick two small bits of double-sided tape (1" x 0.5" each) onto the PCB, then push the solar panel carefully in place. Make sure the wires end up near the points Z+ and Z0 on the other side of the board. The thickness of the tape will give the soldered joints enough room - assuming you didn't use too much solder.
13. Now solder the wires from the solar panel onto points Z+ and Z0.
14. Put the robot on its wheels, so it can start on its way to a better place under the sun.

The `eyes' seek light well enough without adjustment, but can be confused by spots of light on the table or floor. A bit of screening may improve performance - there is room for experiments here.

 

[Mail]   [Home]    [Glavna stranica]

 

For all mistakes on this page and the way how you use it I`m not responsible.