MB1210 - Interface class for the Max Botix ultrasonic rang…

Users » Blaze513 » Code » MB1210

Thomas Hamilton / Mbed 2 deprecated MB1210

Interface class for the Max Botix ultrasonic range finder model 1210. It includes input methods for PWM, Analog, and Serial. A PwmIn class was created to allow the PWM input to be read. Now includes automatic range update via interrupts.

Dependencies: mbed

MB1210.cpp@4:a615b75d4126, 2010-08-28 (annotated)

Committer:: Blaze513
Date:: Sat Aug 28 07:59:29 2010 +0000
Revision:: 4:a615b75d4126
Parent:: 3:05183e50a923

Who changed what in which revision?

User	Revision	Line number	New contents of line
Blaze513	2:997b4057c879	1	//mbed Microcontroller Library
Blaze513	2:997b4057c879	2	//Max Botix Ultrasonic Range Finder MB1210 Interface
Blaze513	2:997b4057c879	3	//Copyright 2010
Blaze513	2:997b4057c879	4	//Thomas Hamilton
Blaze513	2:997b4057c879	5
Blaze513	0:3d969e0b4ca0	6	#include "MB1210.h"
Blaze513	0:3d969e0b4ca0	7
Blaze513	1:b533b95e807a	8	MB1210::MB1210(PinName pw, PinName an, PinName tx, PinName rx) : OperatingMode(0x00),
Blaze513	1:b533b95e807a	9	UnitFactor(1), PwmScalingFactor(17014.5), AnalogScalingFactor(1024), Range(0)
Blaze513	0:3d969e0b4ca0	10	{
Blaze513	0:3d969e0b4ca0	11	if (rx != NC)
Blaze513	0:3d969e0b4ca0	12	{
Blaze513	0:3d969e0b4ca0	13	SerialInput = new Serial(NC, rx);
Blaze513	0:3d969e0b4ca0	14	SerialInput->baud(9600);
Blaze513	0:3d969e0b4ca0	15	SerialInput->format(8, Serial::None, 1);
Blaze513	4:a615b75d4126	16	SerialInput->attach(NULL, Serial::RxIrq);
Blaze513	0:3d969e0b4ca0	17	OperatingMode = 0x02;
Blaze513	0:3d969e0b4ca0	18	}
Blaze513	0:3d969e0b4ca0	19	if (an != NC)
Blaze513	0:3d969e0b4ca0	20	{
Blaze513	0:3d969e0b4ca0	21	AnalogInput = new AnalogIn(an);
Blaze513	0:3d969e0b4ca0	22	OperatingMode = 0x01;
Blaze513	0:3d969e0b4ca0	23	}
Blaze513	0:3d969e0b4ca0	24	if (pw != NC)
Blaze513	0:3d969e0b4ca0	25	{
Blaze513	0:3d969e0b4ca0	26	PwmInput = new PwmIn(pw);
Blaze513	0:3d969e0b4ca0	27	OperatingMode = 0x00;
Blaze513	0:3d969e0b4ca0	28	}
Blaze513	0:3d969e0b4ca0	29	if (tx != NC)
Blaze513	0:3d969e0b4ca0	30	{
Blaze513	0:3d969e0b4ca0	31	SerialOutput = new DigitalOut(tx);
Blaze513	0:3d969e0b4ca0	32	SerialOutput->write(0);
Blaze513	0:3d969e0b4ca0	33	}
Blaze513	0:3d969e0b4ca0	34	}
Blaze513	0:3d969e0b4ca0	35	//constructor dynamically allocates memory and cpu time (interrupts)
Blaze513	0:3d969e0b4ca0	36	//to input objects depending on how the device is connected
Blaze513	0:3d969e0b4ca0	37
Blaze513	0:3d969e0b4ca0	38	MB1210::~MB1210()
Blaze513	0:3d969e0b4ca0	39	{
Blaze513	0:3d969e0b4ca0	40	delete PwmInput;
Blaze513	0:3d969e0b4ca0	41	delete AnalogInput;
Blaze513	0:3d969e0b4ca0	42	delete SerialOutput;
Blaze513	0:3d969e0b4ca0	43	delete SerialInput;
Blaze513	0:3d969e0b4ca0	44	delete this;
Blaze513	0:3d969e0b4ca0	45	}
Blaze513	0:3d969e0b4ca0	46	//input objects must be deallocated
Blaze513	0:3d969e0b4ca0	47
Blaze513	0:3d969e0b4ca0	48	void MB1210::SoundVelocity(float MetersPerSecond)
Blaze513	0:3d969e0b4ca0	49	{
Blaze513	0:3d969e0b4ca0	50	PwmScalingFactor = (UnitFactor * MetersPerSecond * 50);
Blaze513	0:3d969e0b4ca0	51	}
Blaze513	0:3d969e0b4ca0	52	//set the velocity of sound for pwm readings
Blaze513	0:3d969e0b4ca0	53
Blaze513	0:3d969e0b4ca0	54	void MB1210::Voltage(float Volts)
Blaze513	0:3d969e0b4ca0	55	{
Blaze513	0:3d969e0b4ca0	56	AnalogScalingFactor = (UnitFactor * 3379.2 / Volts);
Blaze513	0:3d969e0b4ca0	57	}
Blaze513	0:3d969e0b4ca0	58	//set the voltage correction factor for analog readings
Blaze513	0:3d969e0b4ca0	59
Blaze513	0:3d969e0b4ca0	60	void MB1210::Unit(float UnitsPerMeter)
Blaze513	0:3d969e0b4ca0	61	{
Blaze513	0:3d969e0b4ca0	62	PwmScalingFactor *= (UnitsPerMeter / UnitFactor / 100);
Blaze513	0:3d969e0b4ca0	63	AnalogScalingFactor *= (UnitsPerMeter / UnitFactor / 100);
Blaze513	0:3d969e0b4ca0	64	UnitFactor = UnitsPerMeter / 100;
Blaze513	0:3d969e0b4ca0	65	}
Blaze513	0:3d969e0b4ca0	66	//set the unit factor to return the range in units other than cm
Blaze513	0:3d969e0b4ca0	67
Blaze513	0:3d969e0b4ca0	68	void MB1210::Mode(char Selection)
Blaze513	0:3d969e0b4ca0	69	{
Blaze513	4:a615b75d4126	70	if (SerialInput)
Blaze513	4:a615b75d4126	71	{
Blaze513	4:a615b75d4126	72	if (Selection & 0x08)
Blaze513	4:a615b75d4126	73	{
Blaze513	4:a615b75d4126	74	SerialInput->attach(this, &MB1210::Interrupt, Serial::RxIrq);
Blaze513	4:a615b75d4126	75	}
Blaze513	4:a615b75d4126	76	else
Blaze513	4:a615b75d4126	77	{
Blaze513	4:a615b75d4126	78	SerialInput->attach(NULL, Serial::RxIrq);
Blaze513	4:a615b75d4126	79	}
Blaze513	4:a615b75d4126	80	//attach or detach the interrupt function
Blaze513	4:a615b75d4126	81	}
Blaze513	4:a615b75d4126	82	//interrupts can only be generated if rx pin is connected
Blaze513	0:3d969e0b4ca0	83	if (SerialOutput)
Blaze513	0:3d969e0b4ca0	84	{
Blaze513	0:3d969e0b4ca0	85	SerialOutput->write(Selection & 0x04);
Blaze513	0:3d969e0b4ca0	86	}
Blaze513	4:a615b75d4126	87	//synchronous modes can only be set if tx pin is connected
Blaze513	0:3d969e0b4ca0	88	OperatingMode = Selection & 0x03;
Blaze513	0:3d969e0b4ca0	89	}
Blaze513	0:3d969e0b4ca0	90	//change the operating mode; SerialOutput controls synchronicity
Blaze513	0:3d969e0b4ca0	91
Blaze513	4:a615b75d4126	92	void MB1210::AttachInterruptBuffer(float* Buffer)
Blaze513	4:a615b75d4126	93	{
Blaze513	4:a615b75d4126	94	InterruptBuffer = Buffer;
Blaze513	4:a615b75d4126	95	}
Blaze513	4:a615b75d4126	96	//the user changes the pointer to their own storage area so they can use the interrupt
Blaze513	4:a615b75d4126	97
Blaze513	0:3d969e0b4ca0	98	void MB1210::RequestSyncRead()
Blaze513	0:3d969e0b4ca0	99	{
Blaze513	0:3d969e0b4ca0	100	if (SerialOutput)
Blaze513	0:3d969e0b4ca0	101	{
Blaze513	0:3d969e0b4ca0	102	SerialOutput->write(1);
Blaze513	0:3d969e0b4ca0	103	wait_us(20);
Blaze513	0:3d969e0b4ca0	104	SerialOutput->write(0);
Blaze513	0:3d969e0b4ca0	105	}
Blaze513	0:3d969e0b4ca0	106	}
Blaze513	0:3d969e0b4ca0	107	//hold pin high for at least 20 us to request a synchronous range reading
Blaze513	0:3d969e0b4ca0	108
Blaze513	3:05183e50a923	109	void MB1210::DiscardSerialBuffer()
Blaze513	3:05183e50a923	110	{
Blaze513	3:05183e50a923	111	while (SerialInput->readable())
Blaze513	3:05183e50a923	112	{
Blaze513	3:05183e50a923	113	SerialInput->getc();
Blaze513	3:05183e50a923	114	}
Blaze513	3:05183e50a923	115	}
Blaze513	3:05183e50a923	116	//read characters from the buffer until it is empty
Blaze513	3:05183e50a923	117
Blaze513	0:3d969e0b4ca0	118	float MB1210::Read()
Blaze513	0:3d969e0b4ca0	119	{
Blaze513	0:3d969e0b4ca0	120	switch (OperatingMode)
Blaze513	0:3d969e0b4ca0	121	{
Blaze513	0:3d969e0b4ca0	122	case 0:
Blaze513	0:3d969e0b4ca0	123	if (PwmInput)
Blaze513	0:3d969e0b4ca0	124	{
Blaze513	0:3d969e0b4ca0	125	return PwmInput->pulsewidth() * PwmScalingFactor;
Blaze513	0:3d969e0b4ca0	126	}
Blaze513	0:3d969e0b4ca0	127	else
Blaze513	0:3d969e0b4ca0	128	{
Blaze513	0:3d969e0b4ca0	129	return 0;
Blaze513	0:3d969e0b4ca0	130	}
Blaze513	0:3d969e0b4ca0	131	case 1:
Blaze513	0:3d969e0b4ca0	132	if (AnalogInput)
Blaze513	0:3d969e0b4ca0	133	{
Blaze513	0:3d969e0b4ca0	134	return AnalogInput->read() * AnalogScalingFactor;
Blaze513	0:3d969e0b4ca0	135	}
Blaze513	0:3d969e0b4ca0	136	else
Blaze513	0:3d969e0b4ca0	137	{
Blaze513	0:3d969e0b4ca0	138	return 0;
Blaze513	0:3d969e0b4ca0	139	}
Blaze513	0:3d969e0b4ca0	140	case 2:
Blaze513	0:3d969e0b4ca0	141	if (SerialInput)
Blaze513	0:3d969e0b4ca0	142	{
Blaze513	1:b533b95e807a	143	unsigned char i = 0;
Blaze513	4:a615b75d4126	144	while (SerialInput->readable() && !SerialInput->scanf("R%3f", &Range) && (i < 32))
Blaze513	0:3d969e0b4ca0	145	{
Blaze513	1:b533b95e807a	146	SerialInput->getc();
Blaze513	1:b533b95e807a	147	i++;
Blaze513	0:3d969e0b4ca0	148	}
Blaze513	4:a615b75d4126	149	//find R and parse the range out
Blaze513	4:a615b75d4126	150	return Range * UnitFactor;
Blaze513	0:3d969e0b4ca0	151	}
Blaze513	0:3d969e0b4ca0	152	else
Blaze513	0:3d969e0b4ca0	153	{
Blaze513	0:3d969e0b4ca0	154	return 0;
Blaze513	0:3d969e0b4ca0	155	}
Blaze513	0:3d969e0b4ca0	156	default:
Blaze513	0:3d969e0b4ca0	157	return 0;
Blaze513	0:3d969e0b4ca0	158	}
Blaze513	0:3d969e0b4ca0	159	}
Blaze513	0:3d969e0b4ca0	160	//OperatingMode switches to desired output method;
Blaze513	3:05183e50a923	161	//the result is scaled according to voltage, the speed of sound, and desired unit
Blaze513	4:a615b75d4126	162
Blaze513	4:a615b75d4126	163	void MB1210::Interrupt()
Blaze513	0:3d969e0b4ca0	164	{
Blaze513	4:a615b75d4126	165	*InterruptBuffer = Read();
Blaze513	4:a615b75d4126	166	DiscardSerialBuffer();
Blaze513	0:3d969e0b4ca0	167	}
Blaze513	4:a615b75d4126	168	//this is called whenever an interrupt mode is
Blaze513	4:a615b75d4126	169	//set and a serial rx interrupt is generated;
Blaze513	4:a615b75d4126	170	//it writes to the user's data storage area
Blaze513	0:3d969e0b4ca0	171
Blaze513	0:3d969e0b4ca0	172	MB1210::operator float()
Blaze513	0:3d969e0b4ca0	173	{
Blaze513	0:3d969e0b4ca0	174	return Read();
Blaze513	0:3d969e0b4ca0	175	}
Blaze513	0:3d969e0b4ca0	176	//conversion function acts as shorthand for Read()

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Type:	Program
Mbed OS support:	Mbed 2 deprecated
Created:	22 Aug 2010
Imports:	23
Forks:	0
Commits:	5
Dependents:	0
Dependencies:	1
Followers:	1

MB1210.cpp@4:a615b75d4126, 2010-08-28 (annotated)

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