Chapter 3: Installation and Testing
35
3.10.3.1
Installation of a Neutral Detect switch
To detect the physical neutral position of the throttle potentiometer, many options are
possible. Two options are shown here.
Disk with micro-switch
Mount a disk to the potentiometer shaft. The disk must have a notch, in which the roller of a
micro-switch will fall when the throttle is in the neutral position. Fasten the disk in the correct
neutral position with a screw.
Make sure that the notch is not too deep and that is does not have sharp edges, otherwise
the user may have difficulty to move the throttle out of the neutral position and the disk may
slide out of position during use.
To maximise accuracy, increase the diameter of the disk.
Wear and tear will decrease accuracy. Make sure that the mechanical design conforms to
the required lifespan of the throttle potentiometer.
Disk with optical switch
Many other options are possible, for example a disk with a slit that allows the light of a slotted
optical switch to pass through in the neutral position.
This option provides the advantage that there are no mechanical forces on the disk.
The 'feel' of the throttle to the user is the same, and the chance that the disk will slide out of
position during use is decreased. Also, the optical switch will probably last longer than the
roller of a micro-switch under normal use.
To maximise accuracy, decrease the width of the slit.
Screw
Disk
Pot
Shaft
Notch
Micro
Switch
Screw
Disk
Pot
Shaft
Slit
Optical
Switch
Turn 90˚
and slide
over disk