Eyepiece - an interlude

The new PiCamera has arrived and, at first, I thought that it was dead on arrival ...

For anyone who receives one of these items that doesn't appear to work, you may need to re-seat the ribbon cable at the camera end, and to pop the nano-connector on the board out and back in.

The nano-connector is a little, flat, rectangular connector hidden under the flexi-circuit that emerges from the optical module (the actual camera).

A thumb-nail under the edge of this should separate the two parts, pinch between finger and thumb to re-seat the connector.

Also, for some reason, it takes a few seconds at cold-boot for the Pi to start up with the camera connected.

While I am working with the assembled electronics and doing the prototype work, I needed a temporary case for the camera. An off-cut of black, 1mm art board (cardboard) folded with a suitable hole for the optical module, held together with tape serves well. It is only to provide protection from handling (electrostatic discharge and stray signals from fingers), so it doesn't need to be a permanent (or even terribly attractive) feature.

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I have also turned up a computer-mouse sized, wired, remote module already fitted with a push-to-make switch (to use as a shutter-release) and a neon which will accept a LED 'ready' indicator. The curly cable from an old, serial keyboard will serve for connection.

While waiting for the camera module and playing around with the settings on my Pi, I have been considering the interface between the computer (Raspberry Pi), the physical controls for the next stage of the project (for image-stacking), the remote shutter release and the stepper motor that will operate the fine-focus knob of the microscope.

Because the shutter control will eventually need to send a signal to two Raspberry Pi computers (when I get around to building an eyepiece spectrometer), the button will operate two transistor switches.

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On the subject of the microscope spectrometer, I have decided that, since I will be using a camera as the detector (a PiNoir, infrared-sensitive version of the Pi Camera), there will be sufficient sensor space to handle four simultaneous channels of data - one being the light passing through the specimen. The other three will be a neon discharge tube, a mercury discharge tube and a beam of light direct from the microscope illuminator (delivered via  fibre-optic light-pipe).

This will allow each spectrometer frame to have sufficient calibration data in it to enable direct measurements without having to set up calibration shots and reference illumination sources each time the device is used. Now all I have to do is to find myself a decent, linear transmission grating, since the DVD I was originally planning to use isn't a sufficiently high quality grating for anything but testing (the grating is curved, after all).