Eyepiece - Problems and Successes

For some reason during the past couple of days, while trying to get the configuration on the Pi right, the automatic graphical log-in on the console decided that it wasn't going to work - resulting in the display switching off.

I finally discovered that I could disable the graphical desktop on the console and get the screen to remain switched on indefinitely.

Strangely, (or maybe no so strangely) this speeds up the system by a marked amount.

Rather than have a permanent mess of system messages littering the console when not displaying a camera preview, I have created an ASCII-graphic that displays some information and something to identify the appliance.

The version should be shown as v 0.xx.xx, but whenever I get a production system will be the first release.



I have had a chance to play around with the camera - exploring the dozens of settings that can be changed from software. Some highlights are as follows:

The Automatic White Balance has a selection of profiles that will correct for a  range of lighting conditions.

There is a setting that allows Dynamic Range Compression - giving an insight into shadows and highlights.

There are settings for Shutter Speed, Film Speed, Colour Saturation, Contrast, Brightness and Sharpness amongst other settings.

It is possible to capture images without any of the usual corrections, indeed, it is possible to capture the whole image effectively as it comes out of the image sensor.



I have started writing the camera control software in Python - a language that I have never used before. I have been pleasantly surprised at how easy it is compared with other languages that I have used.

I have reached the point where the camera is switched on, will display a full-screen preview, will warm up before capturing a series of images (with timestamps on the image and on the file name) and will then switch off the camera.

Next comes the work on the user interface - and a way of setting all the controls without having to type in python commands.



I have turned up a salvaged stepper motor that I will be able to use to drive the fine focus knob. It is rated at 24volts, but it should run at 5v with sufficient torque to turn the knob (a very free motion), and to stall at the ends of the fine focus travel - thus allowing detection of the upper and lower limits of motion.

As it is a 4-phase motor, I will be able to drive it with a unipolar control board (so much simpler than H-bridges).