| Project name |
Saxofoon with sensors |
posc_2010_4 |
||
| Date | 1-3-2010 | AJvdB | ||
| Description: |
Electronics on Saxofoon; measuring the valve's |
|||
| Keywords: | saxophone, compact, hall sensor, opamp, magnet, non inverting amplifier with offset |
|||
| Measuring the valves (finger movement) of a saxofoon can be done with hall sensors. Sticking a little neodynium magnet to the moving part creates a moving magnetic field. Wen a hall sensor is placed near the hall sensor, the movement of the valve can be measured. The voltage output of the hall sensor (SS495A1) has a dc offset of 2.5V and changes +/- 500mV when a magnetic field is near (polarity depends of the north- or south-pole). Before connecting the output of the hall sensor to the compact interface, an lopamp circuit (non inverting amplifier with offset) is needed to boost the output, so a better range can be created. Check the opamp-circuit section for more information. In this first prototype I connected 4 hall sensors to some 'easy to acces' places on the saxofoon. This is the first protoype and will be continued in the future. |
Non inverting amplifier with offset adjustment.
