Wednesday, September 17, 2008
Thursday, September 4, 2008
First Game - Flash Cards
A few years ago I made a simple program if you can call it that using Power Point. Simply put it would roll through the letters of the alphabet, and also read the letter aloud. It also included numbers, shapes, colors, animals, and other objects, and phonic sounds for the alphabet.
Now I have decided to learn computer programming, and Microsoft has a great tool set out called XNA that uses C#. With this I am making this same program for Windows and the Xbox 360.
So far it is actually going well, I should have started with Pong, or "Hello World"... But I like a challenge, and I like to learn as much as I can by myself, sometimes just with trial and error. Over the next few days I will post the first screen shots, and soon I will share this program for beta testing with some of my friends that have kids so we can improve upon the ideas.
Hopefully in the end, it will be something that parents find useful. While it will read the letters, we found it better to turn down the sound a bit and engage with our son while using the program. It has fun colors, you can always find them, and it will always be in order!
You might have to worry about slobber on the controller or mouse though.
I started over with the code, here is what you can call an early alpha screenshot (or something). All colors are just temporary, the font is temp, etc.
Working with the PixArt camera directly
This has been a pretty whirlwind past few months. Lots of things have happened, almost none of which procrastineering related which is why I haven't posted anything here. But, one of the things that I have poked at in the past few weeks was creating a PixArt to USB-HID device which allows the camera from the Wiimote to appear as a relatively easy to access USB device. This addresses several problems with using the Wiimote such as running off batteries for extended periods and flakey platform specific Bluetooth drivers. It's also possible to read from the Pixart cam at over 100Hz if you read directly via I2C as well as track visible dots once you remove the IR filter. Of course, none of this was discovered by me. All credit belongs to the numerous individuals who have contributed thier knowledge to the various Wiimote hacking websites. Normally, this project wouldn't be worth a post, but all the information on how to do this is pretty scattered and difficult to follow. So, I figured I would contribute by trying to making this all a bit clearer.
Here's the pinout thanks to kako and a PCB picture. The Reset pin is active low, so use a pullup resistor to Vcc. The Wiimote runs the camera with a 25Mhz clock, but it also works with a 20Mhz clock so you might get away with fudging this a bit. The I2C communication is fast 400Khz and the slave device address is 0xB0. Most microcontroller development platforms should include I2C communication capabilities. If yours doesn't, get a better dev kit =o). Desoldering the camera can be hard with so many pins. But, careful use of a hot air gun will do the trick. The first part is to initialize the camera over I2C. Here's the pseudo code for initializing to maximum sensitivity (actual CCS C code in comments):
- write(hex): B0 30 01
- wait 100ms
- write(hex): B0 00 00 00 00 00 00 00 90 //sensitivity part 1
- wait 100ms
- write (hex): B0 07 00 41 //sensitivity part 2
- wait 100ms
- write(hex): B0 1A 40 00 //sensitivity part 3
- wait 100ms
- write(hex): B0 33 03 //sets the mode
- wait 100ms
- write(hex): B0 30 08
- wait 100ms
It's still somewhat mysterious to me what all these mean, but in this mess is the sensitivity and mode settings described at Wiibrew. The above code uses the sensitivity setting suggested by inio "00 00 00 00 00 00 90 00 41, 40 00" experssed in the 2nd, 3rd, and 4th message. The wait times are conservatively long. After you initialize, you can now read samples from it:
- write(hex): B0 37 //prepare for reading
- wait 25us
- write(hex): B1 //read request
- read 8 bytes
- wait 380us
- write(hex): B1 //read request
- read 4 bytes
This yeilds one sample from the camera containing 12 bytes, 3 for each of the 4 potential points. The format of the data will be the Extended Mode (X,Y, Y 2-msb, X 2-msb, Size 4-bits). The wait timings approximate what the Wiimote does. I've called this routine 1000 times per second without ill effect. Though, I doubt this is actually scanning the sensor and instead is just reporting the contents of an interal buffer. But, people claim 200Hz updates are possible. So, you can use that as a suggestion.
Hooking this up to your microcontroller is pretty straight forward. Give the camera 3.3v power using a voltage regulator, ground, a 20-25Mhz clock, and connect the SDA and SCL lines (don't forget your pull up resistors), and pull up the reset pin.
The CCS C Compiler for the PIC18F4550 includes USB-HID sample code. It's simply a matter of stuffing the data you got from the PixArt camera into the input report buffers for the USB. With this, you could actually create a USB mouse profile and make it control the cursor without any software or drivers at all. If set it up as a full speed device, it's possible to get 1ms reports providing extremely low latency updates. CCS provides relatively affordable PIC programmers as well. Explaining how to set all this up is not within the scope of this post, but it should be plenty to get you started. If you want to make a PCB, you can try ExpressPCB which can get you boards in-hand for as low as $60.
Update 9/6/08: Just a note about the clock. Since my PIC was using a 20Mhz resonator, I just piggy backed the Pixart clock pin off the OSC2/CLKO pin of the PIC which seemed to work fine. Also, Kako has more details (in Japanese) on doing this with an Arduino
Wednesday, September 3, 2008
Alan Wake
Visit Bright Falls for more information on what is surely to be a great game, for those that don't know. It is a psychological action thriller based in the fictional town of Bright Falls, Washington. Alan Wake is a horror writer who battles insomnia, and the stories he writes are based on his nightmares. Light will be a big factor in the game, as it can keep your nightmares away. (think something like "I am Legend" to a degree). For more information head to the FAQ by clicking here. It has the most up to date info, the only people that know more are Remedy themselves...
Remedy is the same team that created Max Payne, and they always push the boundaries of computer entertainment and what we think is not possible on a computer with both graphics and game play. Not to mention the wonderful writing of Sam Lake!
Tuesday, September 2, 2008
Xbox 360 - Lower Prices
360 Pro with 60gb HDD - $299.99 was $349.99
On a side note the 360 HDD's are finally getting a much needed price cut as well.
Jensyn loves Viva Pinata, it is a safe game for the younger ones. The only real violence is well you break pinatas open with a shovel (not required, but seems to happen anyway. Give boy shovel, boy hits objects or shins with shovel), and they have candy inside them! Very cruel actually, and sadly you can also witness this at your local park on most weekends.
