diff --git a/include/validation_tests.h b/include/validation_tests.h
index 5a17fdf..f850431 100644
--- a/include/validation_tests.h
+++ b/include/validation_tests.h
@@ -8,6 +8,7 @@
 #include <global.h>
 #include <DRV_10970.h>
 #include <ICM_20948.h>
+#include <ADCSPhotodiodeArray.h>
 #include <FreeRTOS_SAMD51.h>
 #include <stdint.h>
 #include <comm.h>               /* data packet and transmission functions */
diff --git a/lib/ADCSPhotodiodeArray/src/ADCSPhotodiodeArray.cpp b/lib/ADCSPhotodiodeArray/src/ADCSPhotodiodeArray.cpp
new file mode 100644
index 0000000..754ca99
--- /dev/null
+++ b/lib/ADCSPhotodiodeArray/src/ADCSPhotodiodeArray.cpp
@@ -0,0 +1,70 @@
+#include "ADCSPhotodiodeArray.h"	
+
+/* 
+ * Configure the pins attached to the multiplexer (a-c) as outputs and the pin on analog input as an input.
+ */
+ADCSPhotodiodeArray::ADCSPhotodiodeArray(uint8_t analog_input, uint8_t a, uint8_t b, uint8_t c){
+	// configure digital pins
+	pinMode(a, OUTPUT);
+	digitalWrite(a, LOW);
+
+	pinMode(b, OUTPUT);
+	digitalWrite(b, LOW);
+
+	pinMode(c, OUTPUT);
+	digitalWrite(c, LOW);
+
+	// configure analog pins
+	pinMode(analog_input, INPUT);
+}
+
+/*
+ * Read the value measured on one of the 6 multiplexer channels.
+ */
+int ADCSPhotodiodeArray::read(uint8_t channel){
+	switch(channel){
+		case 0:
+			digitalWrite(a, LOW);
+			digitalWrite(b, LOW);
+			digitalWrite(c, LOW);
+			break;
+
+		case 1:
+			digitalWrite(a, HIGH);
+			digitalWrite(b, LOW);
+			digitalWrite(c, LOW);
+			break;
+
+		case 2:
+			digitalWrite(a, LOW);
+			digitalWrite(b, HIGH);
+			digitalWrite(c, LOW);
+			break;
+
+		case 3:
+			digitalWrite(a, HIGH);
+			digitalWrite(b, HIGH);
+			digitalWrite(c, LOW);
+			break;
+
+		case 4:
+			digitalWrite(a, LOW);
+			digitalWrite(b, LOW);
+			digitalWrite(c, HIGH);
+			break;
+
+		case 5:
+			digitalWrite(a, LOW);
+			digitalWrite(b, LOW);
+			digitalWrite(c, HIGH);
+			break;
+
+		default:
+			digitalWrite(a, LOW);
+			digitalWrite(b, LOW);
+			digitalWrite(c, LOW);
+
+	}
+
+	return analogRead(analog_pin);
+}
\ No newline at end of file
diff --git a/lib/ADCSPhotodiodeArray/src/ADCSPhotodiodeArray.h b/lib/ADCSPhotodiodeArray/src/ADCSPhotodiodeArray.h
new file mode 100644
index 0000000..30e284f
--- /dev/null
+++ b/lib/ADCSPhotodiodeArray/src/ADCSPhotodiodeArray.h
@@ -0,0 +1,30 @@
+#ifndef ADCSPHOTODIODEARRAY_H
+#define ADCSPHOTODIODEARRAY_H
+
+#include <Arduino.h>
+
+/*
+ * Truth table for the multiplexer that the 6 photodiodes will be hooked up to.
+ *  
+ * INPUTS
+ * | A | B | C | CHANNEL | 
+ * -----------------------
+ * | L | L | L |    0    |
+ * | H | L | L |    1    |
+ * | L | H | L |    2    |
+ * | H | H | L |    3    |
+ * | L | L | H |    4    |
+ * | H | L | H |    5    |
+ * 
+ */
+
+class ADCSPhotodiodeArray {
+private:
+	uint8_t analog_pin, a, b, c;
+
+public:
+	ADCSPhotodiodeArray(uint8_t analog_input, uint8_t a, uint8_t b, uint8_t c);
+	int read(uint8_t channel); // select which channel to read from by number
+};
+
+#endif
diff --git a/src/validation_tests.cpp b/src/validation_tests.cpp
index 9ae0d16..7e60512 100644
--- a/src/validation_tests.cpp
+++ b/src/validation_tests.cpp
@@ -149,7 +149,10 @@ void basic_attitude_control(void* pvParameters){
  * @param      pvParameters  The pv parameters
  */
 void simple_detumble(void* pvParameters){
+
     uint8_t mode;
+    uint8_t pwm = 10;
+
     while(true){
         #if DEBUG
             SERCOM_USB.println("[BASIC DETUMBLE] checked mode");
@@ -157,7 +160,14 @@ void simple_detumble(void* pvParameters){
         xQueuePeek(modeQ, &mode, 0);
 
         if(mode == CMD_TST_SIMPLE_DETUMBLE){
-            // TODO: write the detumble test in validation_tests.cpp
+
+            float rot_vel_z = IMU1.gyrZ();
+            if(rot_vel_z > 0){ // spinning clockwise
+                flywhl.run(REV, pwm);
+
+            }else if(rot_vel_z < 0){ // spinning counter-clockwise
+                flywhl.run(FWD, pwm);
+            }
         }
         vTaskDelay(pdMS_TO_TICKS(1000));
     }