Just a quick update. Today I implemented the state machine, which was presented in the last log. Now its possible to to switch between manual and auto mode and use the up and down functions.

In a next step the circuit will be moved from the breadboard towards a pcb and mounted into a case. This allows me to do basic tests on the finished hardware.

To ensure portability and to keep the system modular, I choosed to build a external "power box", that will provide the necessary voltages to drive the camera and the barn door. It also can be used without the tracker and will be fed from a 12 volt battery.

The system needs:

• 3.3 volts, 0.1 (?) amps (atmega)
• 8.2 volts, 2 amps (camera)
• 6.8 volts, 1.7 amps (stepper)

which accumulates ( ;-) ) to about 2.8 amps @ 12 v, using 85% effective step down regulators and pretending that the camera and stepper will draw a constant current. Typical lead-acid batteries provide > 7.2 Ah and therefore a running time up to 2.5 hours. In practice this will last longer, as the system won't draw the maximal current over the time.

I think i'll leave some space for a additional 5 volt output, on which i could connect a Raspberry Pi zero. It could controll the camera using pkTriggerCord or PK-Remote and transform the barn door tracker into a standalone piece o technology.

So the next steps are:

• Building th pcb and case
• Building the barn door hardware
• Testing electronics and hardware
• Design a cycle-saving way to calculate the step time
• Calibrate the step time
• Take some sample pictures and hope for the best
• Buy a raspberry pi zeo :-)