After getting a few uncontrolled variations in some recent prints, I decided to add a light sensor to my Omegalite-D.
Took a few simple supplies: A couple banana plug sockets, a miniature light socket and a CdS cell.
I smashed a small light bulb and soldered the CdS cell to the filiment leads.
Then I soldered a small tube of brass to the base to protect the cell, cut a slot in the brass tube where I can insert ND filters, painted the inside black and the outside white.
Installing only required some drilling in the upper shell. Pretty basic work.
Satisfied with the work but wished I had pointed the sensor to a better "integrated" portion of the dome. As it is I have it pointing towards the ends of the bulb, where there would tend to be more variation than average.
I had done a breadboarded metronome, but I get either no tiks or two tiks per second nothing much else. So if I am going to make that work I'll need some kind of "amplifier" circuit to magnify the resistance changes.
For now, I am just going to use an ohmmeter to monitor the resistance of the CdS immediately prior to test printing and final prints.
Can't justify an RH Designs unit because, after all, it is only an Omega DII. But if I put too many hours into the project I might be looking for a real compensating timer.