Author Topic: 10 pin IR camera daughter board?  (Read 9221 times)

Offline ajw85

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on: May 02, 2011, 12:32:33 PM
I am working on a project that uses the WiiMote IR camera and came across something weird.
This is an OEM Nintendo WiiMote for the Australian / New Zealand market.
After taking the WiiMote apart and desoldering the camera, I realized it had 10 pins and normal camera sensors have 8.
Any ideas what the pin outs for the 10 pins are? I scoured Google searching for 10 pin camera daughter boards but cannot find anything.






Offline Bartimaeus

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Reply #1 on: April 21, 2013, 11:40:58 AM
According to somebody on this page: http://www.stephenhobley.com/blog/2011/03/29/strange-wiimote-camera/

"Itís a 10 pin device, front and back look the same as the fotos Stefan posted (see his post of november 30 for a link).

I do have some fotos of my experiment, a very basic schematic and some 8051 based software for those who are interested.

As I suspected it is indeed an SPI device.
So, if you take a good look at the fotos, youíll see the pin numbers of the device printed on the main board of the wiimote. Taking this numbering into account, the numbers have the following meaning:

1. supply, 3V3
2. !reset (active low reset)
3. gnd
4. 1.8 reference voltage (use for example LM1117-1.8)
5,6. gnd
7. MISO
8. MOSI
9. !SS (active low slave select)
10. CLCK

This device does not require a 24 or 25 MHz clock as the other I2C devices do. Only supply (3V3), reset and the SPI bus.
Iíve made a very basic RC circuit for the reset that seems to do: 15 nF between gnd and pin 2 and a 1.5 kOhm resistor from pin 2 to the 3V3 supply. I wasnít able to determine the original reset circuitry from the wiimote board.

The reference voltage of 1.8 V should be thoroughly decoupled. If you use a LM1117-1.8 for example, use a 10 uF and a 100 nF capacitor in parallel on itís input and another 100 nF on its output. Also the 3V3 supply must be thoroughly decoupled, same set of capacitors as used for the reference does it on my experiment.

The slave select pin 9 should not be tied to gnd continuously. It seems the sensor uses it to capture an image and process the data, so only connect SS to gnd when you actually communicate with the device. The clock (pin 10) does not seem to be critical. Iíve got the device connected to an Atmel 89S52 flash device that does not have an onboard SPI controller. SPI is ďbit-bangedĒ on a few peripheral pins.

There is one important point with this device: ďnormalĒ SPI sends out the most significant bit first. This device does it the other way around, LSBit first, so this must be taken into consideration in your software. Bitswap the commands sent to the device and also bitswap the response received from the device.

The command set is actually the same for this device as for the I2C devices and is accurately described at http://wiibrew.org/wiki/Wiimote#IR_Camera. Just make sure to strip the bluetooth stuff.

"