Diff: rgb_sensor_buffer.cpp

Revision:

0:bbd86bfe6577

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/rgb_sensor_buffer.cpp	Thu Jul 03 16:52:56 2014 +0000
@@ -0,0 +1,107 @@
+/* Discrete RGB color sensor (buffered)
+ *
+ * - uses single-channel light-dependent resistor (via ADC)
+ *   and a RGB LED.
+ * -  compensates background light
+ *
+ * Copyright (c) 2014 ARM Limited
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/* initialize globally */
+#include <mbed.h>
+#include "rgb_sensor_buffer.h"
+
+RGB_SensorBuffer* RGB_SensorBuffer::m_global = NULL;
+
+RGB_SensorBuffer::RGB_SensorBuffer(PinName red, PinName green, PinName blue, PinName adc)
+    :RGB_Sensor(red,green,blue,adc)
+{
+    /* allow only one instance */
+    if(m_global)
+    {
+        m_initialized = false;
+        return;
+    }
+
+    m_global = this;
+    m_initialized = true;
+}
+
+bool RGB_SensorBuffer::__callback(const TRGB &color)
+{
+    return m_global ? m_global->callback(color) : false;
+}
+
+bool RGB_SensorBuffer::callback(const TRGB &color)
+{
+    int avg;
+
+    if(!m_buffer)
+        return false;
+
+    avg = (color.ch.red + color.ch.green + color.ch.blue)/(3*RGB_OVERSAMPLING);
+
+    if(!m_buffer_pos)
+    {
+        /* wait for trigger */
+        if(avg<=m_treshold)
+            return true;            
+    }
+    else
+        /* wait for termination */
+        if(avg>m_treshold)
+            m_buffer_spurious=0;
+        else
+        {
+            m_buffer_spurious++;
+            
+            /* ignore spurious blobs */
+            if(m_buffer_spurious>=RGB_SENSOR_BUFFER_SPURIOUS_COUNT)
+            {
+                m_buffer_pos -= m_buffer_spurious;
+                m_buffer_spurious = 0;
+
+                if(m_buffer_pos<RGB_SENSOR_BUFFER_MIN)
+                {
+                    m_buffer_pos = 0;
+                    return true;
+                }
+                return false;
+            }
+            else
+                return true;
+        }
+
+    /* record color */
+    if(m_buffer_pos<m_count)
+        m_buffer[m_buffer_pos++] = color;
+
+    /* finish after buffer is full */
+    return m_buffer_pos<m_count;
+}
+
+int RGB_SensorBuffer::trigger(TRGB* rgb, int count, int treshold)
+{
+    if(!m_initialized)
+        return -1;
+
+    /* remember settings */
+    m_buffer = rgb;
+    m_buffer_pos = m_buffer_spurious = 0;
+    m_count = count;
+    m_treshold = treshold;
+
+    return (capture(__callback) && wait()) ? m_buffer_pos : -2;
+}