What the circuit does is lower the supply voltage of the ccd when a signal >1,5V is entered on 'IN'.
By lowering the supply voltage most of the electronics on the sensor shut down, stopping the creation of the glow. With most of the electronics on the sensor inactive you wont be able to read data from it, so you have to restore the supply voltage at the time the shutter closes and the sensor readout begins.
The circuit: Q1 is the input stage, it is a high impedance inverter that pulls the cathode of a adjustable zener diode to ground. The anode of the zener is tied to the basis of the output transistor, and to the original supply voltage of the sensor via a resistor. The output transistor is a simple emitter follower; the emitter follows the voltage at the basis - 0.6V. So the output voltage of around 14V is reduced to 13.4V when the circuit is inactive and to a preset voltage (here ~7.5V) when the circuit is active.
Besides the circuit 2 more things are needed;
- a signal to enable/disable lowering the supply voltage
The simplest usable signal i found was the voltage to the green led.
- a way to to steer the signal in the software.
Find a place in capt_seq.c and insert code to turn the led on and off. I inserted the code to turn the led (and the circuit) on after a call that waits for the release of an external remote ("BL wait_until_remote_button_is_released\n" )
The camera turns the led off when the shutter closes (no idea why, but thank you).
Attached: the same exposure with amp off and the circuit (1cmx1.3cm)
