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home:mbhp:make_encoders_out_of_your_mouse [2008/12/01 10:18] (current)
Durisian created
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 +====== Make Encoders out of your mouse ======
 +===== Disclaimer ====
 +The following manipulation has been tested on a logitech M-M35 mouse, with a 
 +"rev C" PCB. There is no guarantee that it will work with other revisions
 +of the PCB, and even less with other models.
 +The content of this page is given to you "as is". I am not giving you any 
 +guarantee of any kind. It is the result of a single test and it doesn'​t
 +mean that it will work the same for you.
 +===== Abstract =====
 +This page focuses on the electronical side of
 +the encoder. It will show you how to connect the
 +PCB of a logitech M-M35 mouse to a DIN.
 +===== Connections =====
 +The following manipulation will let you use ONE of the encoder. ​
 +The mouse needs to be powered by a 5V source. On the picture below, the orange cable
 +(left cable) is the 0V (GND) and the red one(right cable) is the +5V. You can either
 +remove the female connector and solder your cables on the male connector or (like I did)
 +use the original connector.
 +I have removed the other two cables from the connector to use them for the signals
 +of the phototransistors.
 +On the other side of the PCB you need to solder the two cables that will
 +receive the signals from the phototransistors,​ as shown on the picture below.
 +This will let you use the encoder that's on the left on the picture above (on the
 +right on the picture below).
 +If you want to use the other encoder, you'll need to connect two more cables
 +next to the brown and black cables, at their left (not tested yet). 
 +On the DIN board, you'll need to remove the pull-ups resistors, because the
 +phototransistors signals cables already output a stable voltage (either 0V or
 +approx. 5V). I haven'​t tested with the pull-ups resistors on, but I think it
 +won't work, because the mouse PCB works with very low currents.
 +Now connect the other ends of the cables to the DIN board as shown below. The
 +red cable (+5V) is connected to the upper part of the resistor. It isn't very
 +nice, but it works...
 +It isn't a problem if you switch the brown and black cables. It will
 +only switch your encoder'​s counting (ie turning it right will increase values
 +instead of decreasing them).
 +===== Other informations =====
 +==== Observations on the operation of the mouse  ====
 +The IR LED is powered by very short current peaks (PWM)
 +The two IR phototransistors are integrated into
 +one chip. When turning the coded wheel, a 0V is
 +measured on one pin, a 4.8V on a second a pin,
 +and two shifted square signals (0V-4.8V) on the two other
home/mbhp/make_encoders_out_of_your_mouse.txt ยท Last modified: 2008/12/01 10:18 by Durisian