Mouse implemention using Freescale Sensors.

[prabhuu]

Dear all,

Right now, most us use optical mouse. I wish to implement same thing using accelerometer or gyro or magnetometer or combination of these.

So, can you please provide the which of the FreeScale sensor provides the accuracy of 2D (XY plane) motion as that of high precision optical mouse? For our application, higher the resolution, better for us. I do not know, what is the 'g' acceleration that human hand or fingers makes. But, i want to track human hand motion or finger motion or hand writing as accurately as possible. I hope, some expert from freescale knows the answer and sensor part number.

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Thanks

Prabhu.

[michaelestanley]

Prabhu,

As much as I would like to steer you to Freescale products, for desktop mice, optical and/or mechanical ARE the way to go.  Both types give you a better representation than you would get with an accelerometer, which must be integrated in order to get a similar measurement.  Any time you integrate, you integrate signal AND noise.  If the signal is relatively small over time (which it can be for a mouse), the noise can quickly explode.

Having said that, there IS a class of device where you want to go with inertial sensors: air mice.  The Freescale Sensor Fusion Toolbox for Android (which I wrote), includes routines and documentation to demonstrate this functionality.  The application will work with any of the Freescale sensor Freedom shields.  These support virturally all of the consumer grade devices at http://www.freescale.com/sensors.   I have posted documentation for the algorithm on the MIG Accelerated Innovation Community site at air_mouse · memsindustrygroup/Open-Source-Sensor-Fusion Wiki · GitHub .

Have fun!

Mike

[prabhuu]

Dear Mike,

First, thanks for your reply.

I wanted to implement digital pen using freescale sensors.

A more details about digital pen is here :

https://en.wikipedia.org/wiki/Digital_pen

I am okay if error explodes over a period of time (say around after 10-15

seconds). But if for short duration (around 10 seconds) and for short

movements (say around 10-20 cm), if the sensor is able to capture the hand

writing with sufficient accuracy, I am quite okay. So, which of the

Freescale sensors that I can use to implement Digital pen as describe

above. I am oaky if I need to use multiple types of sensors to achieve this

result.

Mike, please let me know if you need more information from side.

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Thanks,

Prabhu.

On Sat, Jun 27, 2015 at 10:59 PM, michaelestanley <

[michaelestanley]

Prabhu,

I would recommend the MMA8451Q accelerometer, which is found in many high performance camera models because of its superior noise and TCO numbers.  The FXAS21002C gyroscope has a low active current (2.7mA) and will pair up nicely with the 8451Q.

Regards,

Mike