Autonomous Flying Platform

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(Blimp Size Calculations)
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  a balloon with a diameter of 2.3 ft
 
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==Blimps for Purchase We could Use==
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http://cgi.ebay.com.sg/52-Mylar-Silver-Blimp-Balloon-Mach-RC-Airship-Blimp_W0QQcmdZViewItemQQitemZ130276783354
  
 
==Serial Connection Information==
 
==Serial Connection Information==

Revision as of 16:27, 19 March 2009

Contents

Overview

A long desire of mine has been to create an autonomous flying solution. I was initially inspired when I saw a competition with the following specifications:

  1. Solution cannot touch the ground
  2. Retrieve a metal ring on the other side of a barrier
  3. Bring it back to its origin and drop it off

The autonomous rc helicopter from Stanford won the competition. Blimps were tried but they flew away etc... in the outdoor winds.

Team Members

Name Expertise Role
Tim Heath Software Developer, Project Management Project Leader/Developer

Requirements

  1. Use a solution that is modular and used as many off the shelf components for rapid prototyping/solutions
  2. Easy to reprogram and loosely coupled
  3. Easy to interface with external control devices
  4. Navigates in 3d space in an efficient easy way

Design

I am going to use the G1 cell phone as it is the most modular.

G1 Info

Property Value
Weight5.6 ounces
Size4.6 by 2.2 by 0.6 inches
Memory1GB (memory card of up to 8 GB possible)
WifiYes
BluetoothYes
USBNon host mode but yes
SerialYes
Camera3 megapixels

Blimp Size Calculations

air is about 1.2 kg/m^3
helium is about 1/6th of that
 6.2 ounces = 175.767043 grams
 then you'd need about 175 liters
180 liters = 6.35664001 cubic feet
((6.3566 * 3) / (4 * pi))^(1 / 3) = 1.14915539
 a balloon with a diameter of 2.3 ft

Blimps for Purchase We could Use

http://cgi.ebay.com.sg/52-Mylar-Silver-Blimp-Balloon-Mach-RC-Airship-Blimp_W0QQcmdZViewItemQQitemZ130276783354

Serial Connection Information

I am by no means a G1 god or guru. There are better people to ask and I
do hope they'll chime in. I am however linked to that nickname that you
dropped and so I feel compelled to answer. ( And no, I'm not nor have I
ever been, a woman. )

The serial interface you're discussing does indeed exist on the HTC
Dream (G1). I hear it's possible to build a cable that is a mini-usb on
one end and a normal sized usb on the other. Between the two is a usb to
serial device. It's just a nice way to have a set of pin outs and power;
it's otherwise not a special cable.

If you have or build such a cable, you'll then be able to access a few
low level debuggers or boot prompts on the serial port. If you have the
right setup, you should be able to connect the cable, attach to the usb
serial device and set minicom to operate at 115200 8N1 (and with no
software/hardware flow control).

A photo of the mythical cable attached to my G1 is available here:
https://www.noisebridge.net/wiki/Image:G1-two-usb-to-serial-cable.jpg

This is the code for that interface (see the Android source):
/kernel/drivers/serial/msm_serial_debugger.c

From the source you'll see the following commands available when the
phone is booted:
pc
regs
reboot
irqs
kmsg
version
sysrq

If you have the developer or engineering boot loader, you can do more...

You can boot the phone with the camera button held down to access a
serial boot prompt that looks like this:
UART0:Cmd>

So far I've only seen a single command 'set'. I didn't find very much
useful information beyond that for the serial interface to the (first?)
boot loader. Perhaps someone knows more about this? It may prove to be
useful...

Another interesting but unrelated (GSM) test function is available in
the dialer program when the phone is booted by calling this number:
*#*#INFO#*#*

Best,
Jake

Serial Hardware to Interface with G1

Untested pinout

Taken from PodGizmo. See website for their pinout.

  1. USB VCC +5v
  2. USB Data -
  3. USB Data +
  4. N / C
  5. USB GND
  6. Left Audio +
  7. Labeled "AG"
  8. Audio - (GND) Labeled "CK"
  9. Switch (Talk) Labeled "OT"
  10. Right Audio +
  11. Mic +
  12. Chassis Ground (GND)


Pinout

it's muxxed on the headset terminals, i think there's some documentation in the h2w source file in arch-msm


  • Picture shows a mini-usb plug going into the G1 indicates only pins 1-5 can be involved. (GND=GND, RX/TX = USB Data +/-)?. I think it is actually an htc plug.. especially considering the google discussion on UART stuff (and that quote above!) Current guess is GND=(AG or CK), TX=Left channel, RX=Right channel.

Helpful Links

Android hacking

HTC Pinout/discussions

Open hardware/source DIY drones

Awsome People

HTC 11pin breakout board (save your sanity)

Personal tools