2008-12-30

Metal Casting

Over the last couple of years I have been dabbling in metal casting. Metals include Pewter, Copper, and Aluminium.

Pewter Casting
At Canterbury Fair in 2006 a NZ knight, Sir Sebastian vom dem
Schwarzwald, taught a class on making soapstone molds and casting with Pewter. After seeing this I was hooked.

Longhouse Token

I wanted to make a nice Event Token for the Arrowsreach Longhouse feast with a Viking theme. Some quick research on Viking hordes turned up quite a few silver pendants and broaches that could be replicated in Pewter.

Dess. nr. 144 Found in a gravesite at Lillevang, Bornholm, Denmark. Dated circa 1,000 A.D. Stylized Viking ship, originally a brooch. Dragon heads clearly depicted on stern. Produced in silver and bronze.
http://uk.turm.dk/dk/default.asp?underside=/dk/pendants.asp

I also found an online store selling similar reproductions in silver. http://www.urweg.com/

Soapstone Mold
Here is the hand carved soapstone mold for the token. Notice the "scratches" to allow the gases to escape when the metal poured. There is a second mold at the bottom of this stone for making vervelles.



Completed Token
Here is the completed token with cord attached.


Touch Lighting Controller

This was created for my nephew, Mark W, as a component of his year 12 high school design project. He wanted mood lighting for a Four Poster Bed.


Touch Sensors
The Capacitive Touch Sensor is similar to this circuit. To simplify the electronics I used the AVR to generate the 20kHz signal and a simplified transistor circuit.

PIR Sensors
The PIR Motion Sensors was bought from JayCar and stripped down and hacked.

RF Remote Control
The reading lights on the bed are 240v halogen lamps and I didn't want to be responsible for electrocuting someone so these are controlled using RF Power Switch devices. The remote control unit was re-wired and is now controlled by the AVR micro.



White LEDs
The bed has 12 White LEDs around the base. These provide mood lighting and turn on and off via touch sensors and PIR motion sensors. They are controlled by the AVR micro and are pulse width modulated to provide dimming.

AVR Micro
The central controller was built using an old AVR 2313 micro (superseded by the AtTiny2313).



My Old Webcams

"Reference Design"
This is the cheapest webcamera that I could find, and at AU$11 you get what you pay for. Bought from http://msy.com.au
  • Name: PC Camera
  • Vendor/Product: 0x0C45:0x613A
  • Bridge Chip: SN9C120
  • Image Sensor: OV7648
  • {{bill:lsusb_microdia.txt|lsusb -v -d 0c45:613a}}
I have tried the following Linux drivers:
  • OVCam Drivers: http://alpha.dyndns.org/ov511/
  • Generic SN9Cxxx http://www.linux-projects.org (closed source)
  • GSPCA / SPCA5xx http://mxhaard.free.fr/
  • Usb Video Class UVC http://linux-uvc.berlios.de/
I'm really not confident in getting this webcam working on Linux. It seems to be very hard to get the chip specifications, which leaves us with reverse engineering and usb packet sniffing. It's probably not worth my time given the crappy image quality.

I have been communicating with Sonix, the maker of the SN9C120 chip, and so far they have stated that they don't release the Register Descriptions or source code. They then said that the SN9C120 was supported by gspca and UVC :-)


Windows Driver Info
The Install disk for Windows says that it is installing "USB PC CAM-168" drivers and applications. This installs an application "C:\Windows\AMCap.exe" and some driver files:
  • Windows INF file {{linux:oem36.inf.txt|oem36.inf}}

Datasheets

GSPCA

I'm running Kubuntu on my laptop, so initially I installed the gspca-source package and used module-assistant to do the compilation. When it didn't recognise the webcam, I modified the gspca_core.c code to include the 0x613a product id by copying the 0x613b code. The commands to try this out are:

sudo -i
./gspca_build
rmmod gspca.ko
insmod gspca.ko debug=5
dmesg | tail

It still doesn't actually work, but it is closer. The camera image is just a gray square with some periodic dots. The problem is probably that the I configured the sensor chip as the OV7660 because there was no entry for the OV7648 yet. Next step is to add the usb and i2c init sequence for this sensor.

Here is a good email about adding sensor support: http://lists-archives.org/spca50x-devs/01093-modifying-settings-for-0c45-613b.html

To capture images from the webcam I am trying out fswebcam from http://www.firestorm.cx/fswebcam/


UVC
[215180.048000] usbcore: registered new interface driver uvcvideo [215180.048000] USB Video Class driver (v0.1.0) [215194.344000] usb 1-1: USB disconnect, address 6 [215201.336000] usb 1-1: new full speed USB device using uhci_hcd and address 7 [215201.496000] usb 1-1: configuration #1 chosen from 1 choice [215201.500000] /usr/src/modules/gspca/gspca_core.c: driver gspca probing [215201.500000] /usr/src/modules/gspca/gspca_core.c: driver gspca allocating memory [215201.500000] /usr/src/modules/gspca/gspca_core.c: driver gspca detecting camera [215201.500000] /usr/src/modules/gspca/gspca_core.c: USB SPCA5XX camera found. SONIX JPEG (sn9c1xx) [215201.500000] /usr/src/modules/gspca/gspca_core.c: [spca5xx_probe:3997] Camera type JPEG [215201.500000] /usr/src/modules/gspca/gspca_core.c: [spca5xx_getcapability:1192] maxw 640 maxh 480 minw 160 minh 120
luvcview version 0.2.1
Video driver: x11
A window manager is available
video /dev/video0
Error opening device /dev/video0: unable to query device.
Init v4L2 failed !! exit fatal


Reverse Engineering
I'm now using the latest source code: gspcav1-20070508.tar.gz

After adding the i2c init sequence for the OV7648 that I reverse engineered from the Windows driver USB packet sniff, I still get the same "test pattern" image as above.

Turn the camera LEDs on by writing 0x44 to the SN9C120 register 0x02 to set the required GPIO lines. This code example uses the usb functions provided in the gspca module code.

__u8 regF1 = 0x44;
sonixRegWrite(spca50x->dev, 0x08, 0x02, 0x0000, &regF1, 1);


QuickCam Express
This camera is operational - more details to come when I get time.
  • Ubuntu (Dapper) kernel quickcam driver
  • Standard v4l applications like xawtv and streamer
$ lsusb
Bus 003 Device 003: ID 046d:0870 Logitech, Inc. QuickCam Express

$dmesg
[254694.256000] usb 2-1: new full speed USB device using uhci_hcd and address 5
[254694.420000] usb 2-1: configuration #1 chosen from 1 choice
[254695.320000] Linux video capture interface: v2.00
[254695.416000] quickcam: QuickCam USB camera found (driver version QuickCam USB 0.6.6 $Date: 2006/11/04 08:38:14 $)
[254695.416000] quickcam: Kernel:2.6.22-14-generic bus:2 class:FF subclass:FF vendor:046D product:0870
[254695.424000] quickcam: Sensor HDCS-1020 detected
[254695.428000] quickcam: Registered device: /dev/video0
[254695.428000] usbcore: registered new interface driver quickcam


Aiptek Pencam

This camera is operational - more details to come when I get time.

GPhoto2 is able to capture and download "preview" photos

$ lsusb
Bus 002 Device 012: ID 2770:9120 NHJ, Ltd Che-ez! Snap / iClick Tiny VGA Digital Camera

$ gphoto2 --auto-detect
Model Port
----------------------------------------------------------
Argus DC-1510 usb:
Argus DC-1510 usb:002,012

$ ghoto2 --capture-preview
Saving file as sq_cap.ppm