| The objective of this project is to modify an X-10 Pan & Tilt mechanism so that it can be controlled by a PIC or PICAXE microcontroller. |
| The unit is normally operated by an RF remote control. The modification will replace the remote control with a three conductor wire that will supply DC power as well as the data pulses that are needed to control the unit. |
| This modification will allow the pan & tilt unit to be placed at least 250 feet from the microcontroller that operates it. The connecting cable only needs three wires, one for 12 volts, one for ground and one to carry the controlling data pulses. In my tests I used Cat 5 twisted pair. Two of the 8 wires in the cable were used for 12 volts, two were for ground and one carried the data pulses. I also connected the data line's twisted pair companion wire to ground. |
| Initial Modification A three conductor cable exits the bottom of the unit. The cable normally connects to a small X10 power supply. It terminates in a female 3 conductor 1/8" phone jack. The tip of the plug carries 12 to 20 volts DC, the first ring is used to activate the unit when the proper house/unit code is selected. The innermost connector is the ground connection. That cable is circled in the photo below. The red wire carries +12, the black wire is ground. The white wire is normally connected to +12 volts when the unit is to be active. To keep the unit working at all times the solder pad that the white lead normally connects to was shorted to the adjoining solder pad that carries 12 volts. This was done under the board in the bottom corner where the label "SP" appears. |
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| The white wire is now being used to carry data pulses that activate the processor on the control board (labeled "P10703K" in the photo here). It is connected to pin 3. As you can see the white wire was extended with a length of yellow wire which is soldered directly to pin 3. It could also have been soldered to the yellow wire that is in the bottom left corner as it also goes to pin 3. |
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Here is another view of the connection.
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In this photo we see (from bottom to top) the PIC circuit board that
is being used for testing. It holds a PIC 16F684
microcontroller, a 5 volt regulator and a few indicator LEDs.
The other circuit is the Radio Control receiver that was removed
from the Pan & Tilt unit. The yellow wire had gone to the
yellow wire on the main circuit board. The white wire
connected to +5 volts and the black wire to ground. So that I could continue to experiment with the radio control I temporarily connected the yellow data wire from the remote control receiver to the data wire that goes to the pan & tilt head. Once that connection is made the unit works once again with the factory remote control. To put control back in the hands of the PIC I just disconnect the remote control receiver's yellow wire and solder the other yellow wire in its place.
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| Software The software listing below is the first working version of the software. It is written in PIC Basic Pro and is for the 16F684 processor. It simply steps through five different commands, left, right, center, up & down. |
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