This board is designed for in-flight characterization of research rocket
motors. It records chamber pressure and acceleration to an on-board flash
memory chip, the contents of which can be downloaded after flight over USB.
-It can also be attached to a [TeleMetrum](../TeleMetrum) or
-[TeleMega](../TeleMega) using the companion interface to allow a subset of
-the data to be included in radio telemetry during the flight.
-
-There is no EasyMotor firmware yet, but it will be part of the
-[AltOS](../AltOS) suite eventually.
-
-Prototypes of v1 were built and evaluated, prototypes of v2 are
-underway. This design is not yet for sale, but we hope to have it on the
-market by mid-summer 2020.
## Features ##
* Designed for use with a battery from 9-12V
* 1.5 x 0.8 inch board
+## Example Installations ##
+
+There are lots of ways to mount an EasyMotor board, but since we've been
+asked, here are a few photos from snap-ring case forward closures
+machined by Bdale for
+test flights of EasyMotor. The sensor bodies are 316 stainless with a 1/8 NPT
+male boss, so the approach chosen is to drill a 1/8 inch touch hole all the
+way through the closure, then drill and tap 1/8 NPT female threads part way
+through the closure thickness. The hole gets filled with grease and the
+sensor screwed in.
+
+The first example is a 98mm snap-ring closure, with the
+sensor and electronics mounted off-center so a 3/8" all-thread could be used
+in the center for motor retention in a minimum-diameter-ish airframe. This
+motor had a small gap between the last propellant grain and the forward
+closure, so having the pressure sampling port off-center wasn't a
+problem. The mounting bracket for the electronics was bent from a bit of
+1/16" aluminum sheet and screwed to the forward closure with two short 4-40
+screws into tapped and drilled mounting holes. Note the use of an A23 12v
+alkaline battery in a holder on the bracket with the
+EasyMotor prototype. These batteries are fine for a flight or two, and both
+they and the little holders for them are cheap on Amazon and make installations
+like this fairly easy to put together:
+
+<a href="photos/IMG_20200905_112722.jpg"> <img src="photos/IMG_20200905_112722-thumb.jpg"></a>
+
+This second example is on a 75mm snap-ring closure, and was Bdale's first attempt
+using 16-gauge steel to bend a mounting bracket that could also be used for recovery
+harness attachment. Another A23 and holder are taped on the other side of the
+sensor not visible in this photo:
+
+<a href="photos/IMG_20200907_101910.jpg"> <img src="photos/IMG_20200907_101910-thumb.jpg"></a>
+
+This example is a refinement of the 16-gauge steel strap used to form a mounting
+bracket and harness retention point, this time for a 54mm snap-ring closure.
+Bdale has flown this setup several times now, and the only down-side is that
+it obvious takes up a few extra inches of airframe length. Note also the quik-link
+wrapped in electrical tape to make sure it doesn't flop down and short against
+any of the electronics in flight. Note also a long piece of shooter wire that
+gets fed through a vent hole in the airframe as a twist-n-tape power switch.
+
+<a href="photos/IMG_20201010_142952.jpg"> <img src="photos/IMG_20201010_142952-thumb.jpg"></a>
+
## Artifacts ##
+The firmware for this product is part of the [AltOS](../AltOS) suite.
+
This board was designed using lepton-eda and pcb-rnd.
The hardware design files are available from
[git.gag.com](http://git.gag.com) in the project
[hw/easymotor](http://git.gag.com/?p=hw/easymotor;a=summary).
+## Availability ##
+
+Prototypes of v2 were built and successfully flown. The initial production
+run is back from our surface-mount assembler, and testing is underway. We
+hope to have these available for sale by February 2021.
projects / web / altusmetrum / blobdiff