Controller on mount
After using this controller and the 400 step/rev motors for months purely as a guiding system I finally started working on the various algorithms needed to turn it into a full-blown GOTO system. This took months of work but I rarely applied more than a few hours a day to the project with long spells of thinking and doing other things. During tuning the PIC In-Circuit Serial Reprogramming interface was installed (the ribbon cable immediately to the left of the 40 pin PIC and the PICkit 2 programming pod is show). The new controller mounts where the original slow-speed stepper system was installed. The leftmost cable at the bottom is for the handbox, while the right cable at the bottom is connected to a RS232 to TTL serial converter (little blue PCB mounted upside down). The bare PCB was about $28 ($80+ for a set of three proto-boards). The PIC chip is about $2.50. The RTC chip is about $3. The motor driver daughter boards sell for about $10 each. The serial converter board was about $3. Connectors and the case plus misc. resistors and capacitors come to about $40. The software implements the basic Celestron NexStar protocol, as documented at the Celestron support site. The system has been successfully tested with both Cartes du Ciel and Stellarium.
Controller on mount
After using this controller and the 400 step/rev motors for months purely as a guiding system I finally started working on the various algorithms needed to turn it into a full-blown GOTO system. This took months of work but I rarely applied more than a few hours a day to the project with long spells of thinking and doing other things. During tuning the PIC In-Circuit Serial Reprogramming interface was installed (the ribbon cable immediately to the left of the 40 pin PIC and the PICkit 2 programming pod is show). The new controller mounts where the original slow-speed stepper system was installed. The leftmost cable at the bottom is for the handbox, while the right cable at the bottom is connected to a RS232 to TTL serial converter (little blue PCB mounted upside down). The bare PCB was about $28 ($80+ for a set of three proto-boards). The PIC chip is about $2.50. The RTC chip is about $3. The motor driver daughter boards sell for about $10 each. The serial converter board was about $3. Connectors and the case plus misc. resistors and capacitors come to about $40. The software implements the basic Celestron NexStar protocol, as documented at the Celestron support site. The system has been successfully tested with both Cartes du Ciel and Stellarium.