Sap flow sensor construction - heating elements

This is the fifth part of a series of videos, were I show you how to make sensors to monitor sap flow. In this video, I show how to coil nichrome wire heaters, which is one of my favorite steps in the whole process to make sap flow sensors.
The heater is coiled at 20 mm, and then stretched to 40 mm, but many other designs are possible. The sensor we build here, can be used with any method that requires a heat pulse. The sensors are built using Type-T thermocouples, and use a nichrome wire as a heater.
The field has moved quite fast, and some of this information might be outdated. However, I am very certain that this information will be very useful to many researchers out there.
Some of these videos were recorded August 2014 and others much earlier. Audio might not be the best, but I tried to restore both audio and video the best I could.
Thank you,
-JGL
Link to our latest sap flow manuscript:
link.springer....
And I sometimes post things I am working on here:
/ gutloja