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Introduction

In this lesson, we will show how to remote control a servo motor via UDP protocol.

19

Description

Tiny and lightweight with high output power. Servo can rotate approximately 180 degrees(90 in each direction), and works just like the standard kinds but smaller. You can use any servo code, hardware or library to control these servos. Good for beginners who want to make stuff move without building a motor controller with feedback & gear box, especially since it will fit in small places. It comes with a 3 horns (arms) and hardware.

Please note, this servo will ‘hold’ the position even when no signal is sent!

To control with an for Arduino, we suggest connecting the orange control wire to pin 9 or 10 and using the Servo library included with the for Arduino IDE (see here for an example sketch). Position “0” (1.5ms pulse) is middle, “90” (~2ms pulse) is all the way to the right, “-90” (~1ms pulse) is all the way to the left.

SG90 Servo Motor Size

Preparation

Hardware:

Software:

Connection

Overhere,we connect the servo to D1 pin.

Upload Sketch

Connect the NodeMCU to computer via USB cable,open this sketch by using Arduino IDE(Version1.6.4+):

Edit the code to fit your own WiFi settings as following operations:

1)Hotspot Configration:

#define STASSID “***” // replace *** with your wifi SSID
#define STAPSK “***” // replace *** with your wifi password

Find above code line,put your own ssid and password on there.

2)UDP local port Settings

         // Define the local port to listen on
        unsigned int localPort = 8888;

We use the “8888” local port here, you can change it to your own local port.

3)Boad & COM Port Settings

After do that,choose the coresponding board type and port type as below,then upload the sketch to the NodeMCU.

UDP APP Settings

About how to config the UDP APP,check this link.

Click the setting icon button, you can see the UDP configration page.

UDP response  text display enable button – Enable text play

UDP Incoming Port – Use this port to listen for and accept connections from remote UDP devices, keep the default setting : “8888”

IP address – Change it to your NodeMCU IP address, you can get the IP address from the Arduino IDE Serial Monitor after the code upload down.

Port – Keep the default setting: “8888”.

Keep other settings as default, then click the “Save” button to save your changes.

Running Result

Upload the code to Arduino board, then open Arduino Serial monitor in the upper right corner.

Now please set your Baud Rate to 115200

you will see NodeMCU IP address as following:

Above result shows your NodeMCU IP address (in my case, 192.168.0.19) , NodeMCU is now waiting for UDP message at port 8888.

Onece the upload done,if wifi hotspot name and password setting is ok and UDP APP is connected, open the Serial Monitor,  when you tap the F1/F2/F3 button on the APP, you will see the servo rotates to corresponding degree.

 

F1(F): Turn to 90 degree;

F2(G): Turn to 180 degree;

F3(H): Back to 0 degree.


FAQ

Question A:  Why could OSOYOO IoT APP send message to NodeMCU without even knowing the IP address of the NodeMCU board?
Answer: OSOYOO IoT APP default destination IP is 192.168.1.255 which is a broadcasting IP address. Broadcasting means the APP will send UDP message to all device in the same Wifi Network.
So even we does not set destination IP address to NodeMCU IP, the NodeMCU can still get the message.

Question B: Can I change default sending destination IP address and Port Number of OSOYOO IoT APP?
Yes, you can! Osoyoo IoT APP default IP is 192.168.1.255 and default port is 8888. If you need to change the setting,
For example, if our NodeMCU IP address is 192.168.0.8, here is the guide to make the change to 192.168.0.8:
1)Open APP, click Setting button in upper right corner
2)Use  192.168.0.8 to replace default IP 192.168.1.255
3)keep default port number 8888 without changing
4)turn on the switch of UDP Response Text Display
5)Click Save button to save the changes you just made
6)Click Back Arrow to go back APP front UI

Question A:  I touched my APP F1 key, but no message shows up in my NodeMCU serial monitor, why?
Sometimes, broadcasting IP Address is not necessarily 192.168.1.255, for example, if your NodeMCU IP address is 192.168.0.8, the wifi network broadcasting IP is 192.168.0.255.
So we suggest you replace 192.168.1.255 with 192.168.0.255 to match your network mask of NodeMCU. Of course you can directly set the NodeMCU IP as destination in APP.

If you have any question about OSOYOO NodeMCU products, feel free to contact us or leave comments here.

In next lesson, we will connect a sensor to NodeMCU and send sensor data to  another  Moquitto client software.

We need to note that ESP8266 is a 2.4G WiFi device, please access to 2.4G network, if you access to a 5G router network, there will be a prompt that the network connection is not successful.

Part details

SKU:  DKRK100700

No. Picture Name Link
1 OSOYOO NodeMCU Board https://osoyoo.store/products/osoyoo-nodemcu-module-usb-c-esp8266-esp-12f-wifi-development-board-with-ch340-for-arduino-ide-micropython-includes-tutorial?variant=41099777638511
2 Servo motor https://osoyoo.store/products/sg90-micro-servo-for-arduino-raspberry-pi-robot?variant=31957821096047
3 LED(6 x White, 6 x Red, 6 x Yellow, 6x Green) https://osoyoo.store/products/led-packs-for-arduino?variant=31957816442991
4 Buzzer https://osoyoo.store/products/piezo-buzzer-module-1pcs?variant=39879251656815
5 Push Button and Hats https://osoyoo.store/products/push-button-and-hats-5pcs?variant=39879253131375
6 Photoresistor(Light Sensor) https://osoyoo.store/products/light-sensor?variant=41099777736815
7 potentiometer(10K lohm adjustable resistor) https://osoyoo.store/products/potentionmeter-10k-adjustable-resistor-3pcs?variant=39879281016943
8 I2C LCD Display (16*2) https://osoyoo.store/products/i2c-1602-lcd-display-module-blue-backlight?variant=41099777933423
9  Temperature&Humidity Sensor Module https://osoyoo.store/products/dht11-temperature-humidity-sensor?variant=41099777998959
10 Resistors https://osoyoo.store/products/osoyoo-electronic-component-kit-total-1390-pcs-led-diodes-30-values-resistors-electrolytic-capacitor-package-ceramic-capacitors-common-diodes-common-transistor?variant=29503912706166
11 4*AA Battery Holder Box https://osoyoo.store/products/battery-box-for-4pcs-aaa-battery?variant=41099778031727
12 4 LED Module https://osoyoo.store/products/4-digit-7-segment-display?variant=41099778064495
13 Stepper Motor +Bridge https://osoyoo.store/products/stepper-motor-with-driver-28byj-48-5v-dc?variant=41099778130031
14 Tlit Sensor Module https://osoyoo.store/products/sw-520d-basic-tilt-switch?variant=41099778162799
15 Infrared Remote Controller https://osoyoo.store/products/infrared-remote-controller-for-arduino-raspberry-pi-microbit-stemmodel-2019011500?variant=31958087532655