Thursday, 11th of March 2010
Thursday, 11th of March 2010
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Scurvy Rat from San Francisco
Member since February 05, 2007
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I've got my nunchuck wired to the Arduino using code from Windmeadow.com -- Thanks Chad!

I wired it up and got it graphing in Processing using the script from Tom Igoe (Thanks Tom).

After I tweak it a bit more, I'll post the code.
After a long hiatus, I'm finally getting time again to play with microcontrollers. I've decided to give the gumstix a rest and play with the Arduino. The user community is more active and there is more code examples to look at. I also have been playing around with Processing (processing.org) and Wire (www.wiring.org.co). Processing is great to get a quick visual of the data coming off the serial.
Stole this from a site...want to get it down for when I need to design the power board.
----

The power dissapation is equal to the voltage drop across the regulator x the current draw.

For example, suppose the supply voltage is 5v, and you're regulating down to 3.3v. This is a 1.7 volt drop. Multiply this by the current, say 100 mA, which equals 170 mW.

If the supply voltage is higher, the dissapation will be greater. A 12v supply would increase the dissapation significantly:

(12 -

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I bought two of these LCDs and the associated connectors from Electronics Goldmine. You can get one here.
For twenty bucks, I couldn't pass it up. Would have preferred to get something with a touchscreen interface, but this is a good size. The datasheet is here.

I followed much of the info on the wiki. Here is the pinouts and connection for my connex 400 (R687):

03 VCC
04
VCC
05
GND
06
GND
07
R0 (Red data input LSB)_________________ _ L_DD13 Pin 08/GPIO(71)
08 R1


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Today was not a good day...

I wanted to reflash with a new kernel enabled for the DS1307 real time clock. I compiled the new kernel and tried to transfer it via serial. For some reason, the transfer would not go through. It would just timeout. I tried several different things and the did something stupid -- I did the uboot commands to erase the flash. Since I couldn't transfer, I now had no bootloader, no FS and no kernel. Bricked. Yell

My gumstix is back to the company to get reflashed.

Lesson
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echO "GPIO out set" > /proc/gpio/GPIO60
echo "GPIO out clear" > /proc/gpio/GPIO60

sets: sets the pin to 3.3v
clear: sets the pin to
0v
set carrier-watch off
set speed 115200
set file type bin
set reliable
fast
set flow-control none
set rec pack 4096
set send pack 4096
set window 5
set prefixing all
Dave Hyland wrote a great program to monitor GPIOs. It can launch a program with the pin # and edge.
More info on the wiki here.

To add a pin use something like this:

gpio-event 58:f:20

to remove the pin do:

gpio-event -- -58:f
I want to connect the gumstix to the gpsstix and the robostix....hmmm....we'll if I connect the gpsstix to the gumstix in the stack, then I can talk to the robostix via I2C using David Hyland's great i2c programs. There are a set of i2c pins exposed on the gpsstix, so I soldered 0.05" headers to those pins and will use the robostix's i2c 0.1" pins (the SDA and SCL are on the UARTS connector).

The robostix's i2c lines run at 5v and the gumstix run at 3.3v, so I need to
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So for this sub to have any navigation I need to develop an IMU. I'll be building and/or buying a strap-down IMU as opposed to a gymballed one.

I've been searching around and the best ones (higher-end hobby ones that is, not military) usually include one or more of these chips:
  1. Freescale MMA7260Q: single IC triple axis accelerometer (details datasheet)
  2. IDG300 Dual-axis Gyroscope (details datasheet)
  3. HMC6352 Dual-axis magnetometer (details datasheet) or PNI's MicroMag3 is an integrated

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Well, today decided I should upgrade u-boot and the filesystem -- wanted to make sure I could do it before I got too far with this project. Also wanted to make I had all the latest and greatest changes.

I tried to follow the instructions here, specifically the ones titles "Flashing over SSH/Ethernet." Turns out they kinda of worked. Everything went through without an error. The only problem was on the reboot, I got the following error:

U-Boot 1.2.0 (Aug 17 2007 - 14:29:48) - 400 MHZ

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Wired up a toggle switch to the robostix in the following manner:


GPIO----------switch--------------GND
|
|------------10k resistor--------Vcc


I have the switch on port c.7 and set the direction to in.

Switch is open
# i2c-io 0x0b getdir c.7
in
# i2c-io 0x0b get c.7
0

Switch is closed
# i2c-io 0x0b get c.7
1
Dave Hylands has written a great little program to read GPIO and ADC pins on the robostix from the gumstix. There are several commands.

Info Retrieves information about the robostix program
Get port.pin Retrieves the value of a pin
Set port.pin val Sets the value of a pin
SetDir port.pin dir Sets the direction of a pin
ReadReg regIdx Reads an 8 bit register
WriteReg regIdx val Writes a value into an 8 bit register

If a GPIO pin is set for input:
1 : pullup resistor enabled
0 : pullup resistor disabled

if

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Followed instructions on:
http://docswiki.gumstix.com/I2c

I used the precompiled sources.

You have to get the i2c bootloader working on the robostix first and this requires that you get an ISP or the gumstix ISP setup (see post). See this wiki entry.

the you can install i2c-Boot-m128-16MHz.hex
uisp --wr_fuse_l=0xbf --wr_fuse_h=0xc2 --wr_fuse_e=0xff (the fuses only need to be set once)
uisp --erase --upload if=i2c-Boot-m128-16MHz.hex

the red LED should start flashing if all went well.

You then need to

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put on code from:
http://docswiki.gumstix.com/Robostix_gumstix_ISP

You can use the gumstix to download files into the robostix flash. Create a jumper which connects Atmel 0 Tx to PXA ST Rx and Atmel 0 Rx to PXA ST Tx on the Robostix. It is the jumpers in the section labeled UARTS near the 60-pin hirose connector. I used an old IDE cable and wired in some jumpers; ugly but works.

# insmod robostix_drv.ko (to remove use rmmod robostix_drv.ko)
# ./uisp
Atmel AVR ATmega128 is found.

Yoohoo!

Now added the

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I2C device node

By default images from buildroot 773 and earlier don't have any i2c-node in the /dev directory. The following command will create one:

mknod /dev/i2c-0 c 89 0
I have one of the newer gpsstix, so it is pre-wired for an active antennae (yes!).

I connected my new active antennae from SparkFun (GPS-00464) to the gpsstix.
The gpsstix has the LEA-4h chip from u-blox.

at first i didn't get any data from
# cat /dev/ttyS2

but when I moved the antennae so it hung outside, i got a lock on satelites.

I copied the script gpsparser.pl from here and started getting good data streams:

Wed Jun 12 18:11:55 2007:37.786106:-122.484671:24.3M:0.112:148.54
Wed Jun 12
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so i hosed the wifi with i stupid typo in /etc/network/interfaces....

i connected my Mac to the gumsix using a KeySpan USB->Serial connector.

used screen as the terminal program:
screen /dev/tty.KeySerial1 115200 cs8 ixoff

I have the console-st board, so it is setup to use the serial port closest to the power connector. The process is:
/sbin/getty -L ttyS0 115200 vt100

Then boot-up the gumstix and got the boot messages and a login prompt. yeah.
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Some info at: http://docwiki.gumstix.org/Buildroot_on_MacOSX

I was installing on a OS X 1.4.9 dual G4 1.25Mhz

installed Subversion 1.4.3
installed wget-1.10.2 http://ftp.gnu.org/pub/gnu/wget/

then ran:
/usr/local/bin/svn co -r1161 http://svn.gumstix.com/gumstix-buildroot/branches/users/osx/trunk/ osx

-r tells the revision number for my gumstix board. found in /etc/gumstix-release on the board when it ships. mine
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Added an old CF I 192MB Sandisk card to the wifistix-CF. it shows up on boot:

Dec 31 16:01:09 gumstix user.warn kernel: hda: SanDisk SDCFB-192, CFA DISK drive
Dec 31 16:01:09 gumstix user.info kernel: Set (GPIO,out,clear) via /proc/gpio/GPIO7
Dec 31 16:01:09 gumstix user.info kernel: Set (GPIO,out,set) via /proc/gpio/GPIO7
Dec 31 16:01:09 gumstix user.warn kernel: ide0 at 0xc4880000-0xc4880007,0xc488000e on irq 50
Dec 31 16:01:09 gumstix user.info kernel: ide-cs: hda: Vpp = 0.0
Dec 31 16:01:09
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Finally got off my but and bought a gumstix computer. Bought the following:

1 x 5.0 volt power adapter  
1 x serial null-modem cable  
1 x console-st  
1 x gumstix connex 400xm  
1 x robostix  

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Ever since they shot footage of the giant squid, it seems you can't avoid squid news. Now the caught the colossal squid. Humboldt squid seem to be moving in the warmer waters up the coast of California. They are ravenous creatures. One report has them attacking a shark that was caught on hook and line. When divers went in, one of them was attacked as well. They grow to 7ft! -- a little scary considering how agile they are in the water.
In Australia, they have developed a cool AUV to monitor coral reefs for problems. It uses vision as its main navigation tool. Here is a shot of the front cameras:
Starbug Vision
Image credit – CSIRO
here is another shot of the whole AUV


Image credit – CSIRO

supposedly it runs on linux. they are working on it so it can see the coral-eating crown-of-thorns starfish. They are working on mass production and they will cost about $24,000 each.

They talk about an innovative propulsion

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Now word comes that there is something bigger....the colossal squid (Mesonychoteuthis hamiltoni). One was found floating whole off of Antartica. Its mantle is larger than the giant squid.  It was first identified in 1925.

Check out this story for more information.

Here is a photo of its beak  in a man's hand.

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These are the solar panels used on the SAUV II. They are discontinued now. Looks like you can get comparable ones for around $400 now.

More on the BP585 Solar panels. They are listed for around $500 a piece.

Found the below information here

The BP-585 is made with 36 of BP Solar's high efficiency laser-grooved buried-grid (LGBG) cells, with an efficiency of conversion of light to electricity of almost 17%, compare to an industry average of between 12.5% and 15%. These are the

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The SAUV II is the second generation Solar Autonomous Underwater Vehicles from the joint work of Falmouth Scientific, Inc., Autonomous Undersea Systems Institute and Technology Systems Inc. and some Navy involvement.

It is a pretty impressive craft. It says you can buy them from Falmouth Scientific...wonder what the cost would be? Looks expensive and hi-end.

It uses Slackware (score one for open source) and PC104 boards as brains. Wonder if there is a cheaper solution...might be pretty
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used in the SUAV II wing structure. sounds expensive...

from here

"Syntactic foam is a lightweight engineered foam consisting of manufactured glass hollow spheres embedded in a resin matrix. These hollow spheres typically range from 10 to 200 microns in diameter and are available in several materials, including glass, ceramic and polymers. This type of system has a very high compressive strength-to-weight ratio."
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Here is a cool thing: solar powered autonomous underwater vehicles. It would cool to build a few and send them out from the coast and see where they can get to...maybe even have them go out and come back...

If you attached a mini-computer with flash ram so when it loses energy it will pick-up where it left off. it would need a small OS and a GPS to find and record its location.

propulsion and submersion

more info here:

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Eric Denton, the British marine biologist died this week. He did a lot of work in many areas, but one of them is related to our friend the giant Squid:

"For example, in collaboration with M.R. Clarke and J.B. Gilpin-Brown, Denton showed that many squid, including the giant squid Architeuthis, use bags of ammonium chloride rather than the air-filled swim-bladders used by bony fish to regulate their buoyancy."

for the whole story go here
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I've been dreaming about building a squid catcher for quite sometime. I think it would need to be:

1. Cheap (why, because I am and you can bet you are going to lose 'em).
2. Able to sense the squid (or other large object)
3. Able to capture some evidence (Camera - still or video)
4. Able to record depth, temperature, etc...
5. Able to surface and send out a beacon of some sort.

I'd love to be able to build 100 of these and drop them off a boat and let them do their polling. After a
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YES!

Finally someone has caught an adult giant squid on video...alive no less.
The same Japanese researcher who shot still photos the year before had the below amazing success this year. Now only if we didn't have to hook them to get the video...


Copyright: Associated Press/Tsunemi Kubodera
Filmed on December 4, 2006 by researchers from the National Science Museum of Japan led by Tsunemi Kubodera.
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