The idea for this sensors started from the following work: http://pei.ucc.ie/daithi/RiverSpy2.pdf
||5 PSI Differential Pressure Sensor, Output Voltage 0-50mV, Voltage Supply 10V
||Multiconductor Cable and Cord, Interference-Reducing Cable, Nonplenum, 300VDC, 22 AWG, 4 Conductors
||Teflon Tubing 50' Length Spool, 20 AWG, ID 0.034", Wall Thickness 0.016", White Translucent
||Loctite Hysol Epoxy Potting Compound, 1.69 oz. (50ml) Dual Cartridge, Black
Epoxy - Various epoxy types used. Primarily used as a sealant, for some devices used as a filler. Other uses include use as electrical potting material.
Silicone Caulk - Used as filler for sensor caps and to prevent water breach into sensor.*
50ml Centrifuge Tubes - Used as case enclosure for sensor device. Multiple brands and distributors used. Any 50ml tube will function so long as the sensor fits inside the tube and the cap is flat on the underside.
Equipment Needed: (Obviously you may use whatever is available, this is just what was used for these probes)
- Wire cutters
- X-acto knife
- Dremel/Rotary tool and appropriate bits
- Soldering iron, solder
- Clamp, stand
- Caulk gun
- Epoxy dispenser gun
Manufacturing the Sensor:
Cut the conductor cable to the appropriate length. (approx 15ft)
Strip a little more than half an inch of insulation from one end and strip the insulation for the individual conductors.
Coat conductor tips with solder as well as sensor leads
Solder conductors to leads
Encase exposed contacts with electrical potting epoxy
Cut teflon tubing to appropriate length, attach to back end of sensor tip, apply epoxy
Cut off-center circular hole into centrifuge tube cap and cut tube (approx. at 35ml mark)
Apply epoxy to front end sensor tip and place into centrifuge tube
Fill excess space in tube with caulk
Seal outer layer of caulk with waterproof epoxy
Attach perforated capsule to surface end of teflon tubing
Mount sensor into mesocosm
Note: Epoxy and caulk curing times will make up primary time consumption; plan accordingly.