Revision 0:57ff45e3cb20, committed 2017-05-30

Comitter:

yxyang

Date:

Tue May 30 06:41:58 2017 +0000

Commit message:

Changed in this revision

diff -r 000000000000 -r 57ff45e3cb20 TSL1401CL.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/TSL1401CL.cpp	Tue May 30 06:41:58 2017 +0000
@@ -0,0 +1,93 @@
+#include "TSL1401CL.h"
+
+TSL1401CL::TSL1401CL(PinName pin_clk, PinName pin_si, PinName pin_adc) : clk(pin_clk), si(pin_si), adc(pin_adc), integration_time(0)
+{
+    clk.write(0);
+    integration_timer.start();
+}
+
+bool TSL1401CL::integrationReady()
+{
+    return static_cast<uint32_t>(integration_timer.read_us()) >= integration_time;
+}
+
+void TSL1401CL::read()
+{
+    integration_timer.reset();
+    integration_timer.start();
+    clk.write(0);
+    si.write(1);
+    clk.write(1);
+    si.write(0);
+
+    for (uint8_t i = 0; i < TSL1401CL_PIXEL_COUNT; i++) {
+        clk.write(0);
+        data[i] = adc.read_u16();
+        clk.write(1);
+    }
+    clk.write(0);
+}
+
+void TSL1401CL::setIntegrationTime(uint32_t int_time_desired)
+{
+    integration_time = int_time_desired;
+}
+
+int TSL1401CL::findLineEdge (uint16_t threshold, uint8_t precision, size_t crop_amount, bool invert)
+{
+    if(precision == 0) precision = 1;
+
+    // Create an array with resolution determined by precision containing the change between points in data
+    uint16_t change_len = (TSL1401CL_PIXEL_COUNT - 2*crop_amount)/precision - 1;
+    int32_t change_in_data[change_len];
+    for(uint16_t i = crop_amount, j = 0; i < TSL1401CL_PIXEL_COUNT - crop_amount - precision; i += precision, j++) {
+        change_in_data[j] = (int)data[i+precision] - (int)data[i];
+    }
+
+    // Find the index of the maximum value in change_in_data
+    uint16_t maxchange = 0;
+    for(uint16_t i = 1; i < change_len; i++) {
+        if(invert) {
+            if(change_in_data[i] < change_in_data[maxchange]) maxchange = i;
+        } else {
+            if(change_in_data[i] > change_in_data[maxchange]) maxchange = i;
+        }
+    }
+
+    // If there isn't a sharp enough change returns -1
+    if((change_in_data[maxchange] >= threshold && !invert) || (change_in_data[maxchange]*-1 >= threshold && invert)) {
+        return maxchange*precision + crop_amount;
+    }
+    else return -1;
+}
+
+int TSL1401CL::findLineCenter (uint16_t threshold, uint8_t precision, size_t crop_amount)
+{
+    if(precision == 0) precision = 1;
+
+    // Create an array with resolution determined by precision containing the change between points in data
+    uint16_t change_len = (TSL1401CL_PIXEL_COUNT - 2*crop_amount)/precision - 1;
+    int32_t change_in_data[change_len];
+    for(uint16_t i = crop_amount, j = 0; i < TSL1401CL_PIXEL_COUNT - crop_amount - precision; i += precision, j++) {
+        change_in_data[j] = (int)data[i+precision] - (int)data[i];
+    }
+
+    // Find the index of the maximum and minimum value in change_in_data
+    uint16_t maxchange = 0;
+    uint16_t minchange = 0;
+    for(uint16_t i = 1; i < change_len; i++) {
+        if(change_in_data[i] > change_in_data[maxchange]) maxchange = i;
+        if(change_in_data[i] < change_in_data[minchange]) minchange = i;
+    }
+
+    // Return the average of the max and min value
+    if(change_in_data[maxchange] >= threshold && change_in_data[minchange]*-1 >= threshold) {
+        return (precision*maxchange+precision*minchange)/2 + crop_amount;
+    }
+    return -1;
+}
+
+uint32_t TSL1401CL::getData(uint8_t index)
+{
+    return data[index];
+}
\ No newline at end of file

diff -r 000000000000 -r 57ff45e3cb20 TSL1401CL.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/TSL1401CL.h	Tue May 30 06:41:58 2017 +0000
@@ -0,0 +1,70 @@
+/*
+ * An mbed library for the TSL1401CL line sensor.
+ * Author: Galen Savidge
+ */
+
+#ifndef TSL1401CLh
+#define TSL1401CLh
+
+#include "mbed.h"
+
+#define TSL1401CL_PIXEL_COUNT 128
+
+class TSL1401CL
+{
+public:
+    /**
+    * Parameters: binary pin connected to clock, binary pin connected to serial-
+    * input (SI), adc pin connected to analog out (AO)
+    */
+    TSL1401CL(PinName pin_clk, PinName pin_si, PinName pin_adc);
+    
+    /**
+    * Returns whether enough time has passsed for integration to complete. The
+    * sensor should not be read until integrationReady() returns true.
+    */
+    bool integrationReady();
+    
+    /**
+    * Reads from the sensor into private data storage.
+    */
+    void read();
+    
+    /**
+    * Sets the integration time of the sensor in microseconds. Can be called mid
+    * integration.
+    */
+    void setIntegrationTime(uint32_t int_time_desired);
+
+    /**
+    * Returns the dark-to-light edge of a line as an int between 0 and cam 
+    * resolution. Returns -1 when no line is found. Use higher precision value 
+    * for fewer samples, default is 1 (lowest, most precise). Ignores 
+    * crop_amount pixels on beginning/end of data. Set invert to true to instead
+    * return the light-to-dark line edge (if found).
+    */
+    int findLineEdge (uint16_t threshold, uint8_t precision = 1, 
+            size_t crop_amount = 0, bool invert = false);
+    
+    /**
+    * Like FindLineEdge, but finds both edges of the line and returns their
+    * midpoint. Returns -1 if either edge is not found.
+    */
+    int findLineCenter (uint16_t threshold, uint8_t precision = 1, 
+            size_t crop_amount = 0);
+    
+    /**
+    * Returns the value of the sensor's last read data at a specified index.
+    */
+    uint32_t getData(uint8_t index);
+protected:
+    DigitalOut clk;
+    DigitalOut si;
+    AnalogIn adc;
+
+    uint32_t data[TSL1401CL_PIXEL_COUNT];
+    uint32_t integration_time;
+    Timer integration_timer;
+};
+
+#endif
\ No newline at end of file