WHITEKNUCKLES
New Member
RustyH's link in post # 26 in the Tank Filler thread got me looking out my own attempt at a fluid level sensor of some years ago.
I tried to make an agricultural type Total Internal Reflection / Refraction optical sensor from scratch.
A 1/4" slice was sawn from 1/4" Perspex, filed square and polished to clear transparency with a 90 degree chisel point at one end.
The other end was stepped at an inward angle to a shoulder square to the length of the Perspex with a small LDR cemented, the end was drilled to accept a small red LED.
My hope of internal reflection down the 2" length of Perspex/air boundary was not realised but wrapping it in blue tape provided results.
In a darkened vassal readadc returns consistent readings of 38 in air against 44 in water with an 08M even though the surface is now somewhat scuffed.
Using IR as in the link will reduce visible light interference and the smaller phototransistor will allow co-linearity.
However in a dark room it is interesting to see where the light spills out from my effort which was intended to point down where this is prohibited with the SST sensor.
No originality is claimed, I was responsible for gazing down at the paraffin level indicator in the Valor heater.
Perspex (Acrylic) rod is readily available and I would be delighted if others experimented with different lengths, coatings, lights and sensors.
Photo is a much reused Picaxe board to show light spillage = ignore the extraneous junk.
[Quote RustyH ....with thanks!
I believe you are looking at beam break IR sensors, the ones Im talking about do not relay on a range, etc
See link in Post # 26
http://www.picaxeforum.co.uk/showthread.php?19832-Tank-filler.../page3
I tried to make an agricultural type Total Internal Reflection / Refraction optical sensor from scratch.
A 1/4" slice was sawn from 1/4" Perspex, filed square and polished to clear transparency with a 90 degree chisel point at one end.
The other end was stepped at an inward angle to a shoulder square to the length of the Perspex with a small LDR cemented, the end was drilled to accept a small red LED.
My hope of internal reflection down the 2" length of Perspex/air boundary was not realised but wrapping it in blue tape provided results.
In a darkened vassal readadc returns consistent readings of 38 in air against 44 in water with an 08M even though the surface is now somewhat scuffed.
Using IR as in the link will reduce visible light interference and the smaller phototransistor will allow co-linearity.
However in a dark room it is interesting to see where the light spills out from my effort which was intended to point down where this is prohibited with the SST sensor.
No originality is claimed, I was responsible for gazing down at the paraffin level indicator in the Valor heater.
Perspex (Acrylic) rod is readily available and I would be delighted if others experimented with different lengths, coatings, lights and sensors.
Photo is a much reused Picaxe board to show light spillage = ignore the extraneous junk.
[Quote RustyH ....with thanks!
I believe you are looking at beam break IR sensors, the ones Im talking about do not relay on a range, etc
See link in Post # 26
http://www.picaxeforum.co.uk/showthread.php?19832-Tank-filler.../page3
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