During certain times while flying I use Carburetor Heat to help prevent carb icing and a possible engine failure. But sometimes, especially during high workload situations, I forget to turn it off which prevents the engine from generating full power and I don't want to be looking down to check the status. So I decided to design something to indicate on my DYNON EFIS when the carb heat is on. In keeping with the "KIS" principle it had to be simple, reliable, cheap to build and easy to install. This is what I came up with.
I used a military grade roller lever switch to sense the carb heat actuator position.
I made a mounting bracket by bending a piece of spare stainless steel. I drilled and tapped the bracket so I could use #6 screws to hold the roller lever switch to the bracket. Then I drilled a hole for a #8 screw to hold the assembly on the carb heat box.
To dampen vibrations felt by the switch I bonded a piece of spare rubber to the bracket with high heat silicone sealant.
The carb heat box already had a convenient mounting location so I used a #8 screw to mount the new assembly near the carb heat actuator. By adjusting the assembly a little, when I move the carb heat knob the carb heat actuator moves the roller lever on the switch.
Carb heat OFF:
Carb heat ON:
I connected one side of the switch to ground and the other to an available contact pin on the DYNON EMS-200 module. After some quick configuration, I now have a light blue indication on my EFIS that tells me if the carb heat is on or off.
Carb Heat OFF:
Carb Heat ON:
Not something drastically needed but simple, effective and I enjoyed the project. You can see more photos of what I did on our
web page.
Carb Heat EFIS Indication
Linear Mode
