Use your ohm meter to find the ground pin on the main connector that is tied to the ground plane. These zero ohm resistors are more cost effective to assemble than soldering jumper wires. The ground islands are all tied together to make a ground plane using resistors labeled 000. All signals are routed on the top layer and they use any leftover copper to make mini ground islands. The picture below shows a typical touchpad. If you can't find any information or you are not sure it's accurate, use the following methods to determine the touchpad connections. If your touchpad has no numbered test points, use all your Google skills to search for any information about your touchpad or the laptop's schematic. The buttons could also be cabled directly to I/O pins on the Teensy.Įlan touchpads use a different test point numbering system as follows: The picture above shows a 4 pin connector that is cabled to the buttons.
#Usb touchpad for laptio serial
The left and right "mouse" buttons are usually cabled to the touchpad board so their on/off status can be included in the serial data stream along with the X and Y movement. If your Synaptics touchpad has numbered test points but T9 thru T13 are not found, the touchpad may use some other protocol. The touchpad shown below is PS/2 but the TM part number does not include any letters. Some possible letters are: P = PS/2, A = ADB, T = TTL, and S = Serial. Some (but not all) Synaptics touchpads have a TM part number that includes a letter to designate the communication protocol. This picture shows a touchpad with numbered test points. You can skip the power filter at T20 which feeds the power pins of the Synaptics chip.
This test point provides an RC power filter. Ground = T23 or solder to the Ground Plane.If T11 is not present (or doesn't work), use T13 or T9 If T10 is not present (or doesn't work), use T12 The typical test point numbers for a Synaptics PS/2 touchpad are: Synaptics touchpads often have round test points that are perfect for attaching wires. The challenge for making any touchpad work is determining the connections for ground, power, clock, and data.
#Usb touchpad for laptio plus
Jump to the end for information on ADB and I2C interfaces plus raw strain gauge and Ergo Trac pointing devices. I will focus on PS/2 touchpads but USB, Serial, ADB (Apple), I2C, or TTL are also used in laptops. " The Teensy microcontroller is at the heart of these projects and it will help you repurpose your old broken laptop. This touchpad project is a companion to my other Hackster project, titled " Laptop Keyboard Conversion to USB.