Arduino, NodeMCU, Programming

Serial Comms between NodeMCU & Arduino Nano

Here’s how to set up serial comms between a NodeMCU V1 (ESP-12E) and Arduino Nano. Note, you could replace the Nano with any Arduino board but I have only tested with a Nano.

Here are parts required:

Here’s the diagram:

circuitAnd the source code is available here: https://github.com/coytar/Snippets/tree/master/NodeMCU_To_Nano

Good luck! 🙂

 

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Android, Kotlin, Programming

HTTP GET using Volley

I was making an Android app using Android Studio (3.1.3) which sends a HTTP GET request. The code was very similar to this:

String serverURL = "http://192.168.0.150/main_light/switch";
URL url = new URL(serverURL);
HttpURLConnection connection = null;
try {
    connection = (HttpURLConnection) url.openConnection();
    connection.setRequestMethod("GET");
    BufferedReader in = new BufferedReader(
    new InputStreamReader(con.getInputStream()));
    //Do something with this InputStream
    // handle the response
    int status = connection.getResponseCode();
    // If response is not success
    if (status != 200) {
        throw new IOException("Post failed with error code " + status);
    }
} catch (Exception e) {
    Log.e(TAG,e.toString());
} finally {
     if(connection != null)
         connection.disconnect();
}

The request was never sent. I tried everything but I just couldn’t make it work. However!

I found a solution using Volley (https://developer.android.com/training/volley/simple). This code is in Kotlin but as you can see it is very simple and mostly importantly it works!

val queue = Volley.newRequestQueue(this)
val url = "http://192.168.0.150/main_light/switch"
val stringRequest = StringRequest(Request.Method.GET, url, null, null)
queue.add(stringRequest)

Don’t forget to add these lines to the AndroidManifest.xml file:

<uses-permission android:name="android.permission.INTERNET"/>
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />

 

Arduino, ESP8266, NodeMCU, Programming

NodeMCU ESP8266 CP1202 Programming (Blink)

This is the tutorial for programming the NodeMCU CP1202 board using the Arduino IDE. The code that will be used is the Blink example. And the board that I’m using looks like this.

Image result for cp1202 nodemcu

Here are the steps I followed:

  1. Install the drivers from https://www.silabs.com/products/development-tools/software/usb-to-uart-bridge-vcp-drivers
  2. Download the ESP8266 board information for Arduino
    1. Open the Arduino IDE
    2. Click on the File menu and then Preferences
    3. In the Additional Boards Manager URLs, enter this: http://arduino.esp8266.com/stable/package_esp8266com_index.json
    4. Click Ok
    5. Click on the Tools menu, click Boards and then click Boards Manager
    6. Wait for it to download the new boards information
    7. Search for ESP8266 and install it
  3. From the Tools menu, select the following:
    1. Board: NodeMCU 1.0 (ESP-12E Module)
    2. Flash Size: 4M (3M SPIFFS)
    3. CPU Frequency: 80MHz
    4. Upload Speed: 115200
    5. Port: (whichever COM port it is)
    6. Erase Flash: Sketch Only
  4. From the File menu, click Examples, click ESP8266 and then click Blink
  5. Compile and download
  6. Voila! 🙂