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--- en:iot-open:practical:hardware:sut:esp32:emb10_1 [2024/02/28 22:09] – [Start] pczekalski
+++ en:iot-open:practical:hardware:sut:esp32:emb10_1 [2024/04/09 12:58] (current) – [Result validation] pczekalski
@@ Line 22: / Line 22: @@
 ==== Task to be implemented ====
 Rotate the servo to the following angles: 0, 90, 180, 135, 45 and back to 0 degrees.
+<note warning>Do not keep the servo rotating when leaving the lab. Implement your code as non-repeating. A servo that remains rotating for a long time may easily wear out its gears, overheat and even burn!</note>
 ==== Start ====
-Check if the servo is in the camera view. Servo is controlled with GPIO 37.
+Check if the servo is in the camera view. The servo is controlled with GPIO 37.
 ==== Steps ====
-// Write some extra information if, i.e. some steps are optional; otherwise, cancel this paragraph (but do not remove the header).//
+**Write your application all in the ''setup()'' function, leaving ''loop()'' empty.**
+<note warning>Do not keep the servo rotating when leaving the lab. Implement your code as non-repeating. A servo that remains rotating for a long time may easily wear out its gears, overheat and even burn!</note>
 === Step 1 ===
-//Describe activities done in Step 1.//
+Include servo control library, specific for ESP32 and declare GPIO, minimum and maximum duty cycle values:
+<code c>
+#include <Servo.h>
+#define SRV_PIN 37
+</code>
+MG 90 servos that we use in our lab are specific. As mentioned above, to achieve a full 180-degree rotation range, their minimum and maximum duty cycle timings go far beyond standards. Here, we declare minimum and maximum values for the duty cycle (in microseconds) and a PWM control channel (2):
+<code c>
+#define PWMSRV_Ch     2
+#define srv_min_us  550
+#define srv_max_us 2400
+</code>
-...
+=== Step 2 ===
+Define a servo controller object:
+<code c>
+static Servo srv;
+</code>
-=== Step n ===
+=== Step 3 ===
-//Describe activities done in Step n.//
+Initialise parameters (duty cycle, channel, GPIO):
+<code c>
+srv.attach(SRV_PIN, PWMSRV_Ch,srv_min_us, srv_max_us);
+</code>
+Hz frequency is standard, so we do not need to configure it.
+=== Step 4 ===
+Rotating a servo is as easy as writing the desired angle to the controller class, e.g.:
+<code c>
+srv.write(SRV_PIN,180);
+delay(2000);
+</code>
-==== Result validation ====
-//Provide some result validation methods for self-assessment.//
 ===== FAQ =====
-This section is to be extended as new questions appear. \\
-When using the printed version of this manual, please refer to the latest online version of this document to obtain the valid and up-to-date list of the FAQ.
-//Provide some FAQs in the following form:\\
-**Question?**: Answer.
-//
+**How do I know minimum and maximum values for the timings for servo operation?**: Those parameters are provided along with servo technical documentation, so you should refer to them. Our configuration reflects the servos we use (MG90/SG90), and as you can see, it goes far beyond the standard servo rotation control that is a minimum of 1000us and a maximum of 2000us. Using standard configuration, your servo won't rotate at full 180 degrees but at a shorter rotation range.
+==== Result validation ====
+Observe the red arrow to rotate accordingly. Remember to give the servo some time to operate.
+<WRAP noprint>
 ===== Project information =====
 {{:en:iot-open:logo_iot_200_px.png?200|}}\\
@@ Line 62: / Line 88: @@
 {{:en:iot-open:ccbync.png?100|}}
 </figure>
+</WRAP>

en/iot-open/practical/hardware/sut/esp32/emb10_1.1709158158.txt.gz · Last modified: 2024/02/28 22:09 by pczekalski