Code improvements

Earlier in 2021 we finally solved some major software stability issues. The C++ code that runs on the Nanopi Neo Air inside the cartridge was crashing relatively often during shooting. Causing loss of captured images.

After long research we found out that this was caused by an imagefile write (the captured image) and an image file read (an image file to monitor the captured result in real time).

By changing the setup of the system, making the Nanopi run its code from fixed eMMC memory (on board the Nanopi) and writing the RAW files to its separate microSD card. The monitor files are read off of the eMMC memory while the RAW files are written to the MicroSD. This avoiding memory acces issues and subsequent code crashes due to segmentation fault.

we now feel confident to continue developing the Digital Super8 Cartridge with software that is reliable enough for the user.

Note: the Digital S8 Cartridge runs on C++ code, while it also has its own WiFi accesspoint and webserver on board. This allows users to run our HTML5 app on their iPhone or smartphone to have full cartridge control and monitoring functionality.

Code update: lighter code, monitoring in color

In an effort to improve the code performance we did a lot of weeding out stuff from the DigitalSuper8 cartridge C++ code. We simplified the code quite a bit and also used Mutexes to prevent multiple threads from trying to alter or test certain variables at the same time. Seems that errors have lessened but more testing is required.

New: Color monitoring while filming
Importantly we managed to ‘upgrade’ functionality with color image monitoring while shooting raw images. It used to be B&W for performance purposes.

Safer multi threading and queuing
Also we are using the Qt framework which is a C++ library framework with added functionality such as threadsafe communications between objects. We changed the code so as to send ‘Mat’ arrays that contain the captured images (using OpenCV libraries for that) from one thread to another, that way achieving a safer queuing mechanism as well.

Monitoring explained
As further Information: the Digitalsuper8 cartridge runs it’s own webserver and WiFi accesspoint so that a user can fully control the functions and settings of the cartridge and can monitor the captured frames in real-time through a browser on a smartphone or iPhone.

How this real-time monitoring works:

Next to capturing and storing RAW images from the Ximea subminiature camera and sensor in the cartridge, the cartridge sends image file names for each captured and written frame to the browser via server sent events. The browser uses that file name info to load the image and display it on the smartphone. So the videostreaming solution is actually a frame by frame retrieving of images at 18 fps by the browser, triggered by server sent events

Cleaning the audio heads of Bauer T610 Super8 projector

Here’s a short tutorial on how to clean the magnetic heads of the Bauer T610 Stereo Super8 film projector. This tutorial is also largely applicable to the T502.

Step 1: open the projector by taking off the front cover. Simply by pulling it away.

pulling away the cover

Step 2: Turn the control knob to its ultimate left turn position, the ‘maintenance’ position.

control knob to ultimate left turn position

Step 3: remove light bulb and light bulb holder (to create space to work).

Step 4: It’s smart to cover the sliders with a piece of paper so that screws and small parts cannot fall into the ‘mixer’ part of the projector.

piece of white paper covers the sliders

Step 5: unscrew the clamp of the first magnetic head, which is the ‘erasure’ head. Take it out. Be very careful: when unscrewing the clamp make sure the screws don’t fall into your projector! Also there is a thin sheet of metal that stays behind in the holder of the magnetic head. Just leave it in place. If by chance it comes out together with the head, make sure to put it back in.

viewing the heads from above
removed audio clamp
Dirty magnetic eraser head

Step 6: clean the head with a cotton tip and some cleaning alcohol (spiritus or similar). And put it back in place. Careful to not lose screws.

Clean head

Step 7: unscrew the clamp of the second magnetic head, the recording and playback head. Similar to the first head: take it out and clean it. Be mindful of the thin metal sheet that is inside the head holder.

unscrewing the clamp
The playback and recording head, note the left and right track pick up elements.
Cleaned head
Dirt and iron residue removed

Step 8: After having put back in place the cleaned playback/recording head, repeat the procedure for the third and final head, which is the ‘monitoring’ head. This head is used for monitoring the audio for example ‘live’ when recording audio with the recording head. The sound lags some 4 frames behind.

Finishing up: after cleaning the monitoring head put it back in place. Put the bulb holder and bulb back in place, close the cover and voilà: you have a Bauer projector with clean heads, able to record and playback crisp