What would it take to turn the USB Arduino into a HID (human interface device)?

You easily turn the Arduino into a small keypad with a few pushbuttons. You could add some variable resistors and make an analog joystick. You could to some tricky stunts with LED's and turn your finger into a mouse pointer. You could make a bio-feedback mouse with some velcro and small coins. But the trick is converting the USB interface from a serial adapter to a HID device. I don't even know if this is possible. But you could build a HIDuino board with the same physical layout (??).

That would make my chording keyboard easy to build...

Neologism: hiduino: Arduino with a HID interface.

I think the next project for my Arduino will use RFID. I plan to get the $40 Parallax RFID Reader and connect it to the protoshield. The RFID module is featured in Make 06 on page 160. Sadly, it won't plug right in on the BlueSMiRF socket, I'll have to add a custom socket on the protoshield. But it looks like it is compatible on the signal level, so I can drive it directly with the Arduino I/O lines. It just takes two: one /ENABLE and one data line.

I'd like to see what the local library uses in their security stickers. They probably all use the same ID so that isn't much to go on, maybe I could use it to find missing library books.

I also want to see if it works with a security card I already have. If I can find a second use for that it would be great. I always carry it with me, so why not use it?

I'm working on using the Arduino board as a programmer for my ATtiny15L chips. The base idea is to send the 15L program to the Arduino board (usb!) and then the Arduino sends the program to the chip using SPI.

The wiring is real easy. I use pin 7 for MOSI, 6 for MISO, and 5 for clock. I put the 15L in the wireless breadboard. I'm also taking 5V and ground from the Arduino also.

The software's the tricky part here. My first attempt just runs a 1Hz signal on SCK (clock, pin 5) to an LED on the wireless breadboard. That's working, so I start sending the 'program enable' bytes on MOSI. A second LED shows that this signal is working. Program enable is 4 bytes, with one byte back during byte 3. So I echo the return byte back up the USB. $A6 is wrong, so I send more debug info up the USB. I'm getting an extra bit somewhere, so I deal with that and get the proper value, $53.

The next step is to check the signature bytes on the tiny15L. It should be $1E $09 $06, but I'm getting $1E $10 $06. Not sure why. Have to sort it out next time.

Eventually I will upload the tiny15 code to a buffer on the Arduino, then a command from the computer starts the upload to the tiny15.

Stay tuned!