A mouse input design. Please help. - Electronic Circuits Projects Diagrams Free

bobolified · 21st February 2006, 01:38 AM

Well what I want to do is similar to a mouse input device. I'm not sure if I want to go with a PS/2 or a USB design. I want to create an input device that has the functionality of a mouse left button when clicked. I took apart Logitech Wheel mouse to see what's inside and I am guessing it has a quadrature encoder from what I read. So do I just need to buy a quadrature encoder?

I did some research on how to design a PS/2 mouse and I found this site:

http://www.computer-engineering.org/ps2mouse/

The author used to provide a link to his full written PS/2 mouse program for PIC16F but it's not there anymore. I'm not sure if I should buy a PIC16F and program it or should I just buy a quadrature encoder? Which is an easier way?

Please any suggestions would be helpful. Thank You.

**Nigel Goodwin** · 21st February 2006, 08:40 AM

PS2 is FAR easier than USB, you can download PIC code from the EPE website - they did an article and a project using it.

eblc1388 · 21st February 2006, 12:01 PM

Quote:

Originally Posted by bobolified

The author used to provide a link to his full written PS/2 mouse program for PIC16F but it's not there anymore.

Here it is. This is the software part only. You can get the whole PDF using the link:

Full PDF on PS2

jbeng · 21st February 2006, 01:59 PM

Quote:

Originally Posted by bobolified

I want to create an input device that has the functionality of a mouse left button when clicked.

Quote:

Originally Posted by bobolified

... should I just buy a quadrature encoder?

Considering your first statement, what function would a quadrature encoder perform here? When the left button on a mouse is clicked, a set of switch contacts are actuated. A quadrature encoder has nothing to do with the switch.
Quadrature encoders are used [in mice] to:
a) provide information to the system regarding mouse movement in the x- and y-axes when they're rotated by the ball moving against the table
b) indicate that the wheel on the unit has been rotated

JB

bobolified · 22nd February 2006, 12:29 AM

The quadrature encoder is what the logitech mouse use to sense x and y position. It doesnt have anything to do with the left mouse button function. I just stated that I think that's what I saw inside the logitech mouse.

I found some of PS/2 mouse controllers that i could use.

PS/2 mouse controllers:

http://www.datasheetcatalog.com/data.../EM84502.shtml

http://www.datasheetcatalog.com/data...2/BU9206.shtml

How would I provide clock inputs for these type of controllers?

I'm not sure which one to use. Has anyone experienced with these type of controllers? Their specs are alright for what I want to do.

mcs51mc · 22nd February 2006, 05:46 AM

Be aware that what you see is not always what you get :?

I once dismantle a HP mouse with a Logitec chip in it. There is no quatratue signal coming out of these opto couplers at all only a coded signal. So there is no way to "see" the 90° shifted pulses or even to reuse these optocouplers as standard light switch (unless you try to break the Logitec code). The connection pins are +5V; 5VGND and code.

I then dismantle a MS mouse with a Zilog chip. Here again no 90° shifted square pulses. The led is driven by a 5kHz signal out of the Zilog chip so the output of the optocoupler is also a 5kHz signal.
When there is no movement of the ball both signals have an amplitude of 1.5V. Once you turn on the ball both signal start to increase to 5V asynchronously. So instead of 90° shift there is a difference in amplitude to detect L/R movement.
The connection pins are +5V; Signal A and Signal B

Hope this helps, at least you don't have to do these measurements again.

View Poll Results: Is it easier to create an input device with PS/2 interface or USB interface?
USB	0	0%
PS/2	9	100.00%
Voters: 9. You may not vote on this poll

Thread Tools
Show Printable Version Email this Page
Display Modes
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode

21st February 2006, 01:38 AM	(permalink)
bobolified	A mouse input design. Please help. Well what I want to do is similar to a mouse input device. I'm not sure if I want to go with a PS/2 or a USB design. I want to create an input device that has the functionality of a mouse left button when clicked. I took apart Logitech Wheel mouse to see what's inside and I am guessing it has a quadrature encoder from what I read. So do I just need to buy a quadrature encoder? I did some research on how to design a PS/2 mouse and I found this site: http://www.computer-engineering.org/ps2mouse/ The author used to provide a link to his full written PS/2 mouse program for PIC16F but it's not there anymore. I'm not sure if I should buy a PIC16F and program it or should I just buy a quadrature encoder? Which is an easier way? Please any suggestions would be helpful. Thank You.

21st February 2006, 08:40 AM	(permalink)
Nigel Goodwin	PS2 is FAR easier than USB, you can download PIC code from the EPE website - they did an article and a project using it. __________________ PIC programmer software, and PIC Tutorials at: http://www.winpicprog.co.uk

22nd February 2006, 12:29 AM	(permalink)
bobolified	The quadrature encoder is what the logitech mouse use to sense x and y position. It doesnt have anything to do with the left mouse button function. I just stated that I think that's what I saw inside the logitech mouse. I found some of PS/2 mouse controllers that i could use. PS/2 mouse controllers: http://www.datasheetcatalog.com/data.../EM84502.shtml http://www.datasheetcatalog.com/data...2/BU9206.shtml How would I provide clock inputs for these type of controllers? I'm not sure which one to use. Has anyone experienced with these type of controllers? Their specs are alright for what I want to do.

22nd February 2006, 05:46 AM	(permalink)
mcs51mc	Be aware that what you see is not always what you get :? I once dismantle a HP mouse with a Logitec chip in it. There is no quatratue signal coming out of these opto couplers at all only a coded signal. So there is no way to "see" the 90° shifted pulses or even to reuse these optocouplers as standard light switch (unless you try to break the Logitec code). The connection pins are +5V; 5VGND and code. I then dismantle a MS mouse with a Zilog chip. Here again no 90° shifted square pulses. The led is driven by a 5kHz signal out of the Zilog chip so the output of the optocoupler is also a 5kHz signal. When there is no movement of the ball both signals have an amplitude of 1.5V. Once you turn on the ball both signal start to increase to 5V asynchronously. So instead of 90° shift there is a difference in amplitude to detect L/R movement. The connection pins are +5V; Signal A and Signal B Hope this helps, at least you don't have to do these measurements again.