DIY Oxygen Analyser Assembly

Updated 28-3-2003

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Parts list
The Printed Circuit Board

internal wiring internal view

The wiring diagram below is for the Lascar DPM125 module and is not to scale. The gold land "3" is shorted with solder to enable the DPM to function as a voltmeter. "DP1" is likewise shorted to activate the proper decimal point. Nothing else needs to be done to the DPM to make it work.

O2 analyser wiring

The cable to the sensor jack plug is taken out of the case via a cable gland.

The image below on the left shows the "expensive" layout whilst that in the centre shows the "budget" version. A piece of blank pcb the same size as the circuit board is used to keep the battery in place (with a little foam rubber to stop it rattling). The drawback is the need to unscrew the box base to replace the battery.
The image on the right is a cutaway side view.

Assembly options

The box:
The box is easily cut (and cracked if you're too enthusiastic). The suggested cutting and drilling for the Lascar meter is shown below, note that a different size hole may be required for other meters. The Anders meter being deeper, it may not fit beneath the battery holder, this may necessitate building the "budget" version above, I'll confirm this when I can get hold of one to try.

analyser box cutting

The images below show a cross-section of the adapter I assembled from various bits and pieces and a photograph of it (without the sensor attached).
I've not gone into detail about this as I'm sure that the average British diver will be able to devise a simpler and more elegant solution.

adaptor cross-section

Below are pictures of a DIN fitting adapter made by Stewart Alan Ball of Hartlepool divers.

Stewart Alan Ball pic1 Stewart Alan Ball pic2

The Printed Circuit Board
Parts list
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Contact: Dave Cordes.