Here’s a little preview of another device in development at PianoPro service. I have
finished the first prototypes of a pneumatic operated electrical switch. This is
a small block which can convert the small amount of air from a tracker bar hole into
an electrical signal.
It is a simple device with a pouch that actuates a microswitch. This microswitch,
like all microswitches, has normally open and normally closed contacts, which can
be used to control other devices.
It has two ports, a supply port and a control port. It triggers the switch with
as little as 3 inches (water) of vacuum applied. This is a very light duty switch,
it needed to be light duty so it could be this sensitive. It can only switch 300mA
of current, so it cannot be used to directly control motors or large solenoids.
These photos show the switch block assembled and an internal view. There is a bleed
cup to ensure fast repetition. The inlet and control ports are standard size for
tracker bar tubing. It measures 1 3/4” x 2 3/4”
This is being developed for use with my BT-001 microprocessor based piano control
system to signal the end of roll. You may find it useful to develop your own rewind
system, or to activate accessories or lights in your piano.
The vacuum switch is close to going into production. The estimated price is $24 plus