Meditech: Camera probe with PI camera

13 Jun 2015

Introduction

The external Meditech camera probe, a Raspberry PI unit that can be detached from the main device, is one of the most versatile probes of the system. This unit will host the PI camera to be used for any kind of video / shooting when needed to see and remotely share (also real-time when needed) images of the environment or the patient. Around the camera lens there is a 12 RGB LEDs ring that can provide several functions:

White light for simple illuminate small dark areas while shooting or making videos
Flashing light for automated iris reactivity test
Specific colours to check possible vision diseases
Other VEP (Visually Evoked Potentials and reactions) based on coloured lights

Pre-assembly

The following image shows the pre-assembly of the probe.

PiFaceCAD usage

To manage the probe while it is not nearby the main device a small user interface should be built so the PiFaceCAD has been adopted. The question was how to manage the Control and Display device with the micro controller while the light ring should also work at the same time, but the display and controller seems using almost all the PI pins.

Instead, while all the PiFace PI boards works controlled by the SPI the display and control continued woking fine also with the RGB LEDs ring connected to the GPIO bus (PWM pin 18). In this prototype version it has been used the Adafruit neopixel 12 ring but the LED component can be found by several distributors, 100 units per package for few cents.

Next step

The following video shows the test of all the components together (the monitor will not be present in the final version). The next step is to build a box for the probe.