USB Missile Launcher
====================

Xmas 2005.  M&S sell a USB missile launcher.
It comes with a poor Microsoft Windows application to
control it.   I was challenged to get it controllable
via a mobile phone, so the first obvious step was to
get the thing controllable from linux via libusb.
This is my efforts so far.

The device is controlled, unusually, via USB HID
class interface SET_REPORT commands
(cf USB HID spec page 52)

These can be sent via lib usb as control messages
with usb_control_msg().   Seems to send two
initiator packets starting with "USBC" to device
endpoint 1, then a bronto 64 byte packet to endpoint 0,
which is the actual variable command to move the
missile launcher.   The first byte is 0, then come
5 bytes which are either 1 or 0 to move the launcher
in a given direction, then two 8 bytes, and then 48
0 padding bytes:

0 left right up down fire 8 8 0 0 0 0 0 0....

The Windows app only ever set one of the direction
bytes at once, but you can actually set more than one
and it works fine -- so you can go up/left at the same
time for example!

It seems picky about timeouts... gotta have a small
usleep() between sending commands it seems.  And if
you just send a movement command, and don't send a
"stop" command (all directions as 0's) then it keeps
moving for a few seconds before finally giving up.
(Doesn't just run to the full extent of its travel
either, oddly)

Code
----

Hacked from various sources, this just grabs the device,
and moves it around a little to show it's working.
I hope someone's going to come along and make a nice
commandline/X11 app out of this before long :-)   If you
do use it, do as you like, but please leave the credits
in the code and drop me an email.


References
----------
USB HID spec:
http://www.usb.org/developers/devclass_docs/HID1_11.pdf

LIB USB docs:
http://libusb.sourceforge.net/doc/


Contact
-------
Ian Jeffray - ian@jeffray.co.uk


Release info
------------
27/12/05 : 0.01 : First release version