How to use a Gyration Gyromouse with Max
The Gyromouse is a wireless input device that uses a very small 2 dimensional gyroscope to measure the angle at which you are holding the device on two axis. Here is a picture:
It also includes a robust wireless link with a range of 40ft. It is a great controller for use with Max applications. I use it to control sound and some moving lights through a Max patch and a LanBox LC+. What's best is that you can get a gyromouse for about $80.
The gyromouse comes with a PS/2 connector and a DB9 adaptor, and can speak either protocol depending on what you plug it into. To use it with Max, you'll need to find, create, or have created for you a special cable, and my serialmouse Max object. You'll also need a free serial port. The help file that comes with the object is pretty explanatory so let me get right to creating the cable, which requires no special equipment and not much knowledge of electrical things.
Note: I did this on a PowerMac 8500/180 which has the old MINI8 serial ports not USB. Gyration now makes a USB adaptor for the gyromouse, so it may be possible to use that to plug a gyromouse into a USB mac. In that case, I don't think you'd need the serialmouse object nor a special cable, and I think you could probably use Adam Schabtach's insprock object available here (click on the "files" section) to interface with Max. You might also be able to use USBOverdrive. If anyone gets either of these to work, let me know. I also think you could use one of the USB-to-old-mac-serial-port adaptors along with the serialmouse object on a USB mac, but I haven't tested this.
Assuming you want to hook a non-USB gyromouse up to a MINI8 serial port, here's how:
The din8 connector on the
back of the mac, looking at it (the "female" side)
The DB9 connector on the mouse (the
"female" side)
The pinout for any PC serial mouse to mac is:
DB9 (mouse) Mac Din8 2 5 Mac RxD- 3 2 Mouse RxD, Mac TxD- (not actually necessary, except see below) 4 1 power 5 4 Ground 6 nothing 7 1 power (yes, both 4 & 7 connect to power)
That should work for most mice (certainly does for the Microsoft Serial Mouse Version 2.0). However, the Gyromouse, and possibly other dual-mode PS/2 and serial mice, needs something more. At the moment that you lift the Gyromouse off the cradle, it looks at DB9 pin3 to see if there is -6V there. If so, it switches into serial mode, which is what we need. Otherwise, it thinks it is in PS/2 mode, or just doesn't work at all. This is why we hook DB9 pin3 to din8 pin2, however din8 pin2 only provides -4.5V. For the Gyromouse, it is very picky and wants to see -6V plus or minus .2V or so. Other mice might not be as picky. The Microsoft Serial Mouse doesn't need anything at all on pin3.
The easy and cheap way to help the Gyromouse is to wire a 1.5V battery (like a C, D or AA cell) between din8 pin2 and DB9 pin3, with the negative side of the battery hooked to DB9 pin3, thus providing -6V for it to look at (it doesn't actually use it, since it has its own external power brick anyway). So that looks like:
|--------------|
_| |
DB9 pin3 ---- | + - | ---- din8 pin2
-| |
|--------------|
This seems to work fine. My electronics friends tell me that a better way to do this would be to wire a 100Kohm resistor in series there to prevent too much power from discharging from the battery into the mac. You could also use a power supply, but then you need to be careful about grounding issues.
For the non electronically minded, here's how I created the cable I needed in the cheap and easy way: I found a cable with the correct din8 connector on it (I used an old printer cable), and cut it somewhere in the middle. I then used an ohm meter, but you could use a battery and a lightbulb, to figure out which color wire corresponded to which pin on the connector. I did the same thing for the DB9 cable, which was an old PC modem cable for me. Then I twisted the right color wires together according to the pinout above (pin 1 from the din8 side gets twisted with pins 4 AND 7 from the DB9 side). For the battery, I used scotch tape to tape the wires for DB9 pin3 and din8 pin2 to the correct side of the battery. It worked fine.
Not wanting to embarass myself in front of my geek friends, I later pulled out the soldering iron and a prototyping board and made the whole thing up nice with a battery holder and a resistor and color coding, etc.
I took the plastic case off the Gyromouse and have been using it mounted to a dancer's head. From time to time, and especially when the gyro gets heated up by the dancer, some drift starts to occur. The Gyromouse is cool in that it automatically fixes this if you put it back on its cradle for a moment. Any kind of radio interference is easily fixed in the same way. I use two Gyromice in the same room and they work fine. I hardly ever experience wireless radio interference, even with cordless phones and wireless stage microphones around. The gyromouse is quite tough - we've dropped them, stepped on them, and sweat on them and they still work. You double-click the bottom button on the Gyromouse to get it to transmit angles constantly. If you leave it off the cradle overnight it runs out of batteries.