add a paragraph about how to hook up a pressure sensor to an EasyMotor

diff --git a/doc/motortest-installation.inc b/doc/motortest-installation.inc
index 3914bc709b1ffbc0d136211601454f9b54547390..778a914ff96b64686f2687ad413a9ba25482c2d6 100644 (file)
--- a/doc/motortest-installation.inc
+++ b/doc/motortest-installation.inc
@@ -57,6 +57,16 @@
                connector, are readily available through various vendors
                including Amazon, eBay, and AliExpress.
 
+               These pressure sensors have three wires and sometimes a 
+               shield around those wires.  The colors of the wires can vary, 
+               but typically are red for power, black for ground, and green 
+               for the analog output.  Hook red to '+5', green to 'PRES', and
+               black to one of the two 'GND' screws on the board.  The other
+               'GND' screw is available for connecting the shield if one is
+               present.  This is mostly relevant if you're using the product
+               for static testing on the ground with a longer than usual
+               cable. 
+
                To log in-flight chamber pressure, a typical approach
                might be to drill a 1/8" sampling hole all the way
                through the center of the motor's forward closure, then
@@ -68,4 +78,5 @@
                If you aren't up for machining closures yourself, 
                link:http://lokiresearch.com[Loki Research] sells 
                54mm and 75mm "experimental bulkheads" with threaded
-               sensor ports that can be used with snap ring cases.
+               sensor ports that can be used with snap ring cases, 
+               and other related mechanical bits and pieces.