Any electronic geniuses out there?

[OuTpaTienT]

Q. Is there any way to increase the transmit/receive radio frequency of my Logitech Cordless Wheelmouse?

Why? (you might ask). Because I just LOVE the freedom of being cordless. But, it conflicts with my love of increased mouse refresh rates (on PS/2 mice). For the sake of those that don't know what I'm talking about. Let me 'splain:

Typical refresh rate of a mouse is 40hz. (The cursor gets drawn to the screen 40 times/second.) Using the PS/2 port, this refresh rate can be increased (without a performance penalty) up to 200hz. At about 80+hz and higher the mouse cursor moves smooth-as-glass. It's very nice on the eyes plus you have control in important tasks like 3D gaming. http://sysopt.earthweb.com/forum/wink.gif

However, due to the radio transmission freq. of my cordless mouse, my refresh rate is limited. I can boost it from 40hz up to 50hz, where it stops. But my regular Wheelmouse (practically identical except for the cord) can have it's refresh rate boosted all the way up to 200hz.

So I figure if I can "overclock" the transmission signal to a higher frequency, I could then utilize a higher refresh rate.

Any ideas?

[narayan]

ok, how do you increasethe refresh rate of the mouse? Sorry, not an answer to your question.

[krusty the klown]

Just what I was thinking!

[U-96]

this is a good start: http://www.rocketdownload.com/Details/Util/ps2rate.htm

as for the original question, no idea, but sounds like an interesting project http://sysopt.earthweb.com/forum/smile.gif

U-96

[Toadman]

/me smells the FCC in the area.. http://sysopt.earthweb.com/forum/smile.gif

[Axel]

One thing which may help you exceed the 50hz limit is to seek out and eliminate sources or radio interference - universal remotes - ceiling fans - microwave ovens - cordless phones - HAM sets, etc. etc.

but other than that, you'd have to alter the transmitter/receiver units at the motherboard and at the mouse itself. If you got extremely creative, you might try buying a cordless headset and cannibalizing it for it's sender/receiver units as the frequency range on those things is a bit wider to accomidate analog sound signals, but that's all that comes to mind.

[OuTpaTienT]

hmmmm, that's a beginning of an idea there Axel.

I shouldn't have to mess with the motherboard in any way, just the transmitter in the mouse and possibly the receiver in the Logitech receiving unit.

Where else should I look for this type of info, or ask this question?

[tonym]

Outpatient,

Do you know what the communication frequency of the mouse to receiving unit is?? I suspect that it's in the 10's of Megahertz range. So increasing the refresh rate to 100 or 200Hz shouldn't be that much of a problem.

Does the documentation that you received with the mouse have a declaration of conformance to the FCC and IEC (CE)?? That should give you a clue as to the transmission frequency. Just let me know what it is and I'll do some research on what's inside the mouse/receiver!


Tony

[Richard_Cranium72]

As Axel said, shield the cords on AC and anything else that might "cross talk" from the 60hz emissions from the power cords, don't forget the little ac/dc power converters in the wall can exceed 30+milligauss within 1 ft, this is enough to cause interference in some cases. Also a small step in the direction of increasing frequency, is using Energizer or Duracell "Industrial" alkaline batteries. These put out 1.62-1.65vdc instead of 1.50 for standard alkalines. Forget the rechageables as the Ni-Metal Hydride are 1.36vdc and Ni-Cads are 1.25. Anyway, the increased voltage should increase the output frequency, unless the chip has a constant voltage stabilizer in it. No opinion there as to what is in your mouses' board.

[OuTpaTienT]

Natually I don't have any documentation any longer. However, printed on the circut board inside the receiver is this:

Mouse1 - 27.045MHz
Kybrd1 - 27.095MHz
Kybrd2 - 27.145MHz
Mouse2 - 27.195MHz

There's 3 crystals (little silver canisters) labelled:
HKC 16.420
10.1700 TC
10.3200 TC

And inside the mouse I find printed on the PCB:
27.045MHz
27.195MHz

with two nearby crystals labelled:
HKC 13.5975
HKC 13.5225

Once, back in the "olden days" I replaced a crystal on a 486 motherboard to allow for a increased speed CPU (went to 66MHz from 33MHz CPU). Would something along those same lines work here? Or is everything so sensitive &/or finely tuned to the specified frequencies that it wouldn't be so simple?

[OuTpaTienT]

uh......hello?

[Paul V]

The frequency at which the device transmits and the frequency with which the device operates should be pretty much independant.

I can't help you much more, my area is all in digital computing, computer logic, with only a smattering of analog circuitry and no real signal analysis as yet. I don't know enough about signal modulation/demodulation to be of any help here, sorry.

[tonym]

Outpatient,

I've been in and out of the office for the past few days. Business would be GREAT without those **** customers ;^)

Give me a few days to find out what's really goingon inside that mouse of yours. If the doggone thing is trnasmitting at 27MHz or so, then changing the mouse refresh parameter to even 500Hz shouldn't be a problem! There has to be another "clock", a very low frequency one at the 60Hz frequency in your mouse or on the board in the receiver, that acts as a "gate" for how often the mouse movement events are detected and presented to the mouse port. My guess is that this resides in the receiver.

But I'll find out for sure when I get back from Maine (sometime late Sunday nite!!!!)!

Until then, be (out)patient or see if you can either fanagle a set of schematics from Logitec Tech Support! or draw out the circuit that's in the mouse and reciever -- if it's not all that complicated (i.e. two-sided PCB and marked components!).

[I just re-read your original post. What do you mean by "...I can boost it from 40Hz to 50Hz, where it stops."?

What do you use to adjust the rate, a trimpot in the receiver or is it a setting in the software supplied with the unit???]


Tony

[This message has been edited by tonym (edited 05-04-2000).]

[OuTpaTienT]

Thanks Tony. http://sysopt.earthweb.com/forum/smile.gif

It's a tiny software program I used to boost the rate, PS/2rate, a small freeware utility to increase the PS/2 sampling rate. However, I'm not currently using it because the most recent Logitech Mouse drivers (9.0) have a built-in rate slider that does the same thing.

Another neat little program is this mouse rate checker that tells you the sampling frequency of the cursor as it passes over it's window. It's a super tiny program and you can find it here: http://tscherwitschke.de/download.html


Thanks for any assistance with this idea. I really do like my $60 cordless mouse but need the higher refresh rate.