Finn Lassen wrote:

You know all those electrical air valves left over after stripping off a
13B or 20B pollution control systems?

Instead of paying $16 - $25 for several air pressure sensors, why not
use those electrically controlled air valves to make an input
multiplexer leading to just one air pressure sensor?

Finn

Wonderful idea Finn. Those things are super cheap or free as most people
throw them away. Save those electric air valves folks and send them
to me if you don't plan on doing any pressure measurements.

Paul Lamar

I ran right outside to the garage and took a picture of my first gen RX7
solenoid valves. Sixteen of these, a pressure sensor and a 74154 one
of sixteen data selector chip hooked to four data output lines on a PIC
is all you need to make 16 pressure measurements in and around your
cooling system. Should work on intake and exhaust manifolds as well.
Great idea Finn. Major cost breakthrough. No reason not to take some pressure
measurements. I look forward to gathering some important information
in the near future.

Paul Lamar

Here is another picture. Don't throw these away folks. Send them to me.
I'll pay shipping.

One of the beauties of Finn's idea is you don't have to tape
drip irrigation tubing all over the outside of your airplane.
You can just use one or more of these RS232 module under the cowl
and just run three or four RS232 wires into the cockpit to the computer.

The vertical pipe from the top is connected to the horizontal pipe on the
right when the device is activated. When it is not activated it is
connected the the filter on the left and the pipe on the right
is closed off.

The DC resistance is about 37.6 ohms so you will need a solenoid driver
chip ULN2003 (.75 cents DigiKey.com) or transitors to drive the solonoid. 
It takes about .3 amps to activate.

Paul Lamar
 
The AirCraft Rotary Engine NewsLetter.  Powered by Linux.
ACRE NL web site. http://home.earthlink.net/~rotaryeng/            
Copyright 1998-2002 All world wide rights reserved.