Well in an effort to have a cheep DRO I figured I'd end up using the mouse encoders to interface with the parallel port using the DRO software that reads the parallel ports from http://www.lindsayengraving.com/othe...rests/dro.html Using encoders from PS2 microsoft type mice
Anyway I couldn't find much out there on mouse mutilations that didn't use Logitech mice. And of course I've long since tossed all my Logitech mice which I liked a lot but simply wore out. But I do happen to have a LOT of MS mice.
Of course they are built different. The out put of their IR sensors is different then I think the Logitech ones are based on some of the schematics I've seen on the web.
The MS mice use 1 IR emitter and 1 sensor which has 2 outputs which produce the oscillating output signals to determine direction. The encoders used in the http://www.lindsayengraving.com/othe...rests/dro.html I think output negative pulses which trip the PNP transistors to signal the 5v to the parallel ports. Looking at the Microsoft mouse circuit board it was kinda easy to see the sensors were going to send hi output when triggered rather then low so connecting to PNP transistors like they did on the lindsyengraving site wouldn't work.
Anyway I'm just dangerous enough with electronics and transistors to know when things work. But in any case in my experimenting I connected the Encoder signals from the MS mouse to some NPN transistors then watched how the LED's pulsed. Took a little bit to figure out which pin's of the mouse chip (once removed) needed to be used (follow the circuit board layouts) but once powered with 5v I was getting signals to the NPN transistors and was able to watch some connected LED lights blink on and off as I spun the wheel... Success.
Now the problem was to convert that signal to PNP so I could send 5v to the parallel port.
To do that I connected the output of the NPN transistors to some 4N25 optical isolators (pin 1 to the NPN transistor and 2 to ground). That triggered the optical transistor on the other side and that (pin 4 ground and 5 to PNP) triggers the PNP transistors . The rest of it is the same as Lindsy engraving's site. to the parallel port.
The mouse bodies are mounted to the mill and a simple rubber band running around the crank shafts with some PVC slipped and shrunk around the shafts to guide the band a little bit.. the band goes around the signal wheel triggers the signals. After getting it dialed in with the dro software it works Really good. Took something like a .00004725 count offset in the software to get it counting right with the signals.
I had a handful of mice to play with. and while the mouse chip for the most part had the same pin outs for reading the sensors (pin 1 and 2 for x and pin 3 and 4 for Y Pin 5 was positive) one of the mouse needed 6,11,12 to ground and the other just needed 6 and 12 and had an extra transistor on it which had to be removed and bridged with negative.
I did find how ever non of my P2 gate way boxes would work at all. Stupid gateway parallel ports not standard? Ended up using one of my P1 machines I have laying around.
Anyway sorry for the long post. Hopefully I will have some pictures of the work and schematics up soon. My descriptions of things probably isn't really good enough for the non brave to try but couldn't wait to talk about it.
Here are some pics of the 2 different mice I used and the circuit boards.
notice the one pic of the mouse circuit board before then after. see the missing transistor. Not sure what the reason was for this transistor but it needed to be removed and one leg grounded to get ground to the sensors.
The other mouse did not need this and only needed pins 6,11,12 grounded
pin 5, on both got 5v positive (borrowed from the PC's power supply red wire)
pins 3 and 4 are signals from the 1 sensor (Y up and down on the PC screen) used in each mouse. pins 1 and 2 would be used if you wanted to use signals from the (X side to side) sensor in the mouse.
Wires from pin 3 and 4 go to the NPN transistors then the output of those go to the 4N25 optcial isolators, and the out put of the isolators trigger the PNP transistors which output goes on to the parallel port.
Well it interfaces the sensors in a microsoft mouse to the PC parallel port so you can use those sensors with the DRO program given out on the http://www.lindsayengraving.com/oth...erests/dro.html site or other sites which happen to have added to that base program code some what.
Basicly I guess you could discribe it as the ultra ultra cheep man's DRO seeing that the circuits and transistors are all of a couple dollars and ya can pic up used mice for free or almost free (if you work in an office or have an old computer store around)
But the point was to get it working with the Microsoft type mice (ie PS2 port mice) as it is impossiable to find the old serial logitec mice to do this with which I have seen being used on some old web sites..
Also I still have yet to get the interface to work with any of my older P2 gateway parallel ports (on the mother boards) no matter what the settings in bios are. Not sure what the deal is there. So I have it connected to one of my older P1 machines and it works fine.
I'm a layman my self so not sure if my terms are very clear.
Just mouted the Y axis this morning. I ended up ditching the PVC tubes I used as guide helpers for the rubber belts (bands) for some larger O ring seals I had around. The were 1.75 ID rubber 0 rings then I hot glued around the out side edge of them to hold them in place on the shaft. The PVC tubes had slight eregularitys after I heated them to fit them on. the edges would rub on the bands a little and it just didn't work as well as the rubber o rings.
Here is the circuit diagram I built to interface the mouse output to the parallel port.
the 5v and ground are leached off the ground and red wires from the computers power supply.
Just repeat the schematic for how ever many axis you have.
Playing with the DRO last night I found it to be quite accurate. Might be more accurate if I could find better rubber bands. Also I'm considering increasing the diameter of the mouse incoder wheel shafts by slipping a tube or something over it then the rubber band on that.
Guess accuracy might vary depending on age of the mouse parts and quality of rubber bands but I have found playing with it that for free it does really darn good for me anyway.
You can solder to pin 1 or 2 of the mouse chip (after removing the chip) for the 1 axis in the mouse. In both the mice I used I solder to pin 3 and 4 of the chip because of the direction I mounted the mice.
Last edited by wcarrothers; 02-12-2005 at 05:18 PM.