Digital: fuel pressure gage; boost gage

[Robert W. Hughes]

> > Is it possible to use the pressure sensing device in a digital scale to
> > build such things as an electronic fuel pressure gage, or an electronic
> > boost gage, or a boost control?
> 
> My guess is that a scale uses a strain gauge of some sort. To use it
> as a pressure sensor you'd have to have some kind of A/B diaphragm
> arrangement. Can be done, but ick.
> 
I took one of these bathroom scales apart one time. It was a plain old
spring balance with a round disc where the readout scale disc would have
been. This disc had a series of lines printed around the outer edge and
ran through a LED-sensor assembly. The display driver just counted the
lines going by as the disc rotated due to a load. Real cheap, simple,
but not much use as a pressure gauge.
-- 
Robert W. Hughes (Bob)
BackYard Engineering
Houston, Texas
rwhughe at hal-pc.org