Alternative parts, Mouse speed calculation, I. shiftbrite app – Pololu Wixel User Manual
Page 51: Overview, Installation instructions
A Wixel controlling a chain of ShiftBrites.
• invert_x: Set to 1 to invert the horizontal movement of the mouse. Default is 0.
• invert_y: Set to 1 to invert the vertical movement of the mouse. Default is 0.
• speed: A positive number that determines the speed of the mouse. Default is 100. This speed is linearly
proportional to this number.
Alternative Parts
You could replace the battery pack with a single 9 V battery and a step-down regulator that outputs voltage within
the Wixel’s 2.7–6.5 V operating range, such as our
, or you could use a 1- or 2-cell holder along with an appropriate step-up voltage regulator, such as
our
.
You could replace the accelerometer by any other
whose
outputs are equal to one half of the input voltage when the acceleration on the corresponding axis is 0.
Mouse Speed Calculation
The mouse speed is calculated from the measured acceleration vector of the device. The acceleration vector normally
points straight upwards and has a magnitude of 1 g due to the Earth’s gravity. The Wixel measures the X and Y
outputs from the accelerometer, which tell it the components of the device’s acceleration vector in the plane of
the accelerometer. The resulting two-dimensional vector is then multiplied by its own magnitude to achieve greater
control at lower speeds. The vector is then multiplied by the speed parameter to convert it into a mouse speed which
is reported wirelessly to the computer.
9.i. ShiftBrite App
Overview
This app allows you to wirelessly control a chain of one or more
RGB LED modules at a
distance of 50 feet or more from a PC. You will need two Wixels to
set up the wireless link: one connected to the ShiftBrites, running
the ShiftBrite app, and one connected to your PC with USB, running
the Wireless Serial App (
). Using a terminal or your own
software, you can send a series of hex characters indicating the
desired color for each module to the virtual COM port. The
characters are transmitted wirelessly, received by the remote Wixel,
decoded, and sent to the ShiftBrite chain, causing each module to
light up with the specified color. Approximately 1000 color
commands can be sent per second, allowing large displays or
smooth animations.
The ShiftBrite App is also compatible with the
, which uses the same
control electronics.
Installation Instructions
Follow the instructions for the Wireless Serial App in
to set up and test a basic wireless serial
link between two Wixels, using the latest version of the Wireless Serial App. Download the
(20k wxl). Open it with the Wixel Configuration
Utility, choose your settings, and write it to one of the Wixels. See
for more information on how this is
done.
Pololu Wixel User's Guide
© 2001–2014 Pololu Corporation
9. Wixel Apps
Page 51 of 64