A1301

Arduino library for A1301 and A1302 magnetometer.

Description

The A1301 and A1302 are continuous-time, ratiometric, linear Hall-effect sensors. They are optimized to accurately provide a voltage output that is proportional to an applied magnetic field. These devices have a quiescent output voltage that is 50% of the supply voltage. Two output sensitivity options are provided: 2.5 mV/G typical for the A1301, and 1.3 mV/G typical for the A1302. (from datasheet)

sensor	sensitivity	support
A1301	2.5 mV/Gauss	Y
A1302	1.3 mV/Gauss	Y
A1324	5.000 mV/Gauss	N
A1325	3.125 mV/Gauss	N
A1326	2.500 mV/Gauss	N

Other, more or less, compatible sensors are welcome. (see future)

The library is experimental and need more testing. Feedback, issues and improvements are welcome, Please open an issue on GitHub.

Connection

//  always check datasheet.
//    PIN    A1301
//    ===============
//     1     GND
//     2     DATA
//     3     VDD +5V

Interface

Constructor

HALL(uint8_t pin) base class constructor. pin is the analogPin to read from.
A1301(uint8_t pin) constructor.
A1302(uint8_t pin) constructor.

Configuration

void begin(float voltage, uint16_t steps) Sets the parameters voltage and number of steps of the internal ADC. Note this allows to update the voltage runtime.
void setMidPoint(float midPoint) the value of midPoint depends on the internal ADC. It is the value where there is no (zero) magnetic field. Note it does not need to be a whole value. This allows quite precise tuning.
float getMidPoint() returns the current midPoint.
void setSensitivity(float sensitivity) overrule default sensitivity. Use with care.
float getSensitivity() return current sensitivity.

Read

float raw(uint8_t times = 1) raw analog measurement.
float read(uint8_t times = 1) raw measurement converted to Gauss. Can be positive (North) or negative (South).
float readExt(float raw) to be used with external ADC. Can be positive (North) or negative (South).

Analyse

boolean isNorth() idem.
boolean isSouth() idem.
float lastGauss() returns last measurement in Gauss.
float prevGauss() returns previous measurement in Gauss.
float Tesla(float Gauss) convenience convertor.
float mTesla(float Gauss) convenience convertor.
float uTesla(float Gauss) convenience convertor.

Operation

The examples show the basic working of the functions.

Future

Must

improve documentation
buy hardware A1301 / A1302 / ...
test with hardware (again)

Should

plotter example
unit tests

Could

boolean isSaturated()
float findZero() how exactly.
printable interface
Possible compatible
- HoneyWell - SS39ET/SS49E/SS59ET
- HoneyWell - SS490 Series
add derived classes for - A1324/25/26 ?

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