Hard iron distortion compensation for 3 axis magnetometer

This paper presents the way how the hard iron effect could be compensated and a way to implement it on a small power device such as a microcontroller. Because of the magnetized materials that can stay near a magnetometer sensor and because of the very small magnetic field of the Earth, before the use of the measured values from a magnetometer to determine the heading (angle with the N direction) of the sensor a compensation is needed

Full-Text Search Engine using MySQL

In this article we will try to explain how we can create a search engine using the powerful MySQL full-text search. The ever increasing demands of the web requires cheap and elaborate search options. One of the most important issues for a search engine is to have the capacity to order its results set as relevance and provide the user with suggestions in the case of a spelling mistake or a small result set. In order to fulfill this request we thought about using the powerful MySQL full-text search. This option is suitable for small to medium scale websites. In order to provide sound like capabilities, a second table containing a bag of words from the main table together with the corresponding metaphone is created. When a suggestion is needed, this table is interrogated for the metaphone of the searched word and the result set is computed resulting a suggestion