Commodore 64 Fiddling Quintin Myers I know you like to hear of unusual projects related to PV power, so here is a new one for you. During these long winter evenings I decided to fiddle with my trusty old Commodore 64 (actually a SX-64 portable with built-in disk drive and color monitor that I modified to work on 12V). First I took the Bat-O- Meter circuit from HP#10, removed the LEDs, and plugged the leads into the joystick ports. Then I took some telephone wires, hooked them to the "USER" port data lines, and put IRFZ-30s at the other end. Then I wrote a simple BASIC program to take advantage of these new inputs and outputs. Now I have a programmable load controller/regulator. The computer uses about 7 watts with drive and monitor off. It senses voltage in 1/2 volt resolution. It records voltage records throughout the day, displays them graphically on the screen, stores this data on disk, prints graphs, etc. I use it to control a ceiling fan, pump, and resistive load, so far, for voltage regulation. It can control up to nine loads without any additional logic circuitry. This summer I plan to use it to control a swamp cooler, fan, open and close vents, and control an active tracker. I'm sure more uses will come to mind. Quintin Myers, 19344 Kiowa Rd., Bend, OR 97702, 503-382-4633