Version 46 (modified by Eric Hazen, 4 years ago) (diff)


CW DOSI Probe for Cancer Monitoring

The proposed probe contains six pairs of LEDs, one photo-detector assembly and drive electronics. Each of the 12 LEDs may be selected individually, with external drive current controlling the output intensity.

The LED pairs are arranged in a circle with a 25.4mm radius, with the photodiode assembly in the center.

A single flexible, multi-conductor cable provides power and control. The HDMI cable seems like a reasonable off-the-shelf solution (with mini-HDMI type C connector on the probe)

Updated Version (2019)

This is documentation for the V3 probe design by Fraunhaufer. EDF is assisting in a new manufacturing run starting March 2019.

NOTE: The LEDs vary in whether they have an Anode polarization mark or Cathode polarization mark. Due care must be taken when preparing assembly documentation !!

The layout V3_1.1 expects one of each, so the two packages are reversed on the silkscreen.

Obsolete Versions

Initial (Rigid PCB) Design

Revised (Flex PCB) Design


  1. The 74HCT154 is attractive because of the very small package, but has active-low logic outputs. This requires a small change in the schematic. The control interface should be unchanged. Alternatively, the 4514 decoder is available in a TSSOP24 package which is about 7mm x 8mm

Interface Cable

Pinout for micro HDMI

NOTE NOTE NOTE: uHDMI and standard HDIMI pinouts are different!

Pin uHDMI Pin HDMI Pin DOSI Use Notes
1 - Hot Plug Detect/HEAC-
2 - Utility/HEAC+
3 1 TMDS Data2+ Photodiode+ Photodiode Anode
4 2 TMDS Data2 Shield Photodiode GND Shield for Photodiode signal
5 3 TMDS Data2- Photodiode- Photodiode Cathode
6 4 TMDS Data1+ LED Power Power for LEDs
7 5 TMDS Data1 Shield AGND Shield for LED power
8 6 TMDS Data1- AGND Ground for LEDs
9 7 TMDS Data0+ A1 Address 1
10 8 TMDS Data0 Shield DGND Logic GND
11 9 TMDS Data0- DGND Logic GND
12 10 TMDS Clock+ LE Latch enable
13 11 TMDS Clock Shield DGND Logic GND
14 12 TMDS Clock- DGND Logic GND
15 13 CEC A0 Address 0
16 17 DDC/CEC/HEAC Ground DGND Logic GND
17 15 SCL/DDC clock A2 Address 2
18 16 SDA/DDC data A3 Address 3
19 18 +5V power VCC Logic power (3.3V-5V)