ESP8266 controlled with Android app (MIT App Inventor)

The schematics for this project are very straight forward. You only need to establish a serial communication between your FTDI programmer and your ESP8266. You can buy one FTDI programmer on eBay.

Wiring:

RX -> TX
TX -> RX
CH_PD -> 3.3V
VCC -> 3.3V
GND -> GND

Uploading Code

You should see a window similar to the preceding Figure, follow these instructions to upload a Lua file:

Connect your FTDI programmer to your computer
Select your FTDI programmer port
Press Open/Close
Select NodeMCU+MicroPtyhon tab
Create a new file called init.lua
Press Save to ESP

Everything that you need to worry about or change is highlighted in red box.

Code

Upload the following code into your ESP8266 using the preceding software. Your file should be named “init.lua“.

Don’t forget to add your network name (SSID) and password to the script below.

-- Rui Santos
-- Complete project details at http://randomnerdtutorials.com

wifi.setmode(wifi.STATION)
wifi.sta.config("YOUR_NETWORK_NAME","YOUR_NETWORK_PASSWORD")
print(wifi.sta.getip())
led1 = 3
led2 = 4
gpio.mode(led1, gpio.OUTPUT)
gpio.mode(led2, gpio.OUTPUT)
srv=net.createServer(net.TCP)
srv:listen(80,function(conn)
    conn:on("receive", function(client,request)
        local buf = "";
        buf = buf.."HTTP/1.1 200 OK\n\n"
        local _, _, method, path, vars = string.find(request, "([A-Z]+) (.+)?(.+) HTTP");
        if(method == nil)then
            _, _, method, path = string.find(request, "([A-Z]+) (.+) HTTP");
        end
        local _GET = {}
        if (vars ~= nil)then
            for k, v in string.gmatch(vars, "(%w+)=(%w+)&*") do
                _GET[k] = v
            end
        end
        
        if(_GET.pin == "ON1")then
              gpio.write(led1, gpio.HIGH);
        elseif(_GET.pin == "OFF1")then
              gpio.write(led1, gpio.LOW);
        elseif(_GET.pin == "ON2")then
              gpio.write(led2, gpio.HIGH);
        elseif(_GET.pin == "OFF2")then
              gpio.write(led2, gpio.LOW);
        end
        client:send(buf);
        client:close();
        collectgarbage();
    end)
end)
view raw Projects/ESP8266_Controller.lua

Schematics

Now follow these schematics to create the circuit that controls two LEDs.

Your ESP IP Address

When your ESP8266 restarts, it prints in your serial monitor the ESP IP address. Save that IP address, because you’ll need it later.

In my case, the ESP IP address is 192.168.1.95. If you experience problems seeing your IP read this troubleshooting guide.

Creating the Android App with MIT App Inventor

MIT App Inventor is a drag-and-drop software that allows you to create a basic, but fully functional Android app within an hour or less.

Here’s how to edit the ESP8266 Controller app:

Click here to download .zip folder that contains .aia file
Unzip the folder
Go to MIT App Inventor
Click the “Create Apps” button on the top right corner
Go to the “Projects” tab and select “Import project (.aia)”

After importing the .aia file, you’ll be able to edit the app and see how the app was built.

Designer

The designer tab is where you can edit how the app looks. Feel free to change the text, change the colors, add buttons or add more features.

Blocks

The blocks section is where you can add what each button does and add logic to your app.

Click the image above to enlarge the figure

After finishing editing the app you can click the “Build” app tab and install the .apk file in your Android. I personally recommend that you first upload the app provided below to ensure that everything works as expected (later you can edit the app).

Installing the Android App

Follow these instructions to install the default app that I’ve created:

Click here to download .zip folder that contains the .apk file
Unzip the folder
Move the .apk file to your Android phone
Run the .apk file to install the app

Here’s how the ESP8266 Controller app looks when you to open it.

ESP8266 Controller

It’s very easy to configure. Click the button “Set IP Address” on the bottom of the screen and type your IP address (in my case 192.168.1.95).

You’re all set!

Now you can turn the GPIOs high and low with your smartphone. Go to the top of this page to see a video demonstration of this project.

Taking It Further

This is a basic example that shows you how easy it is to integrate an Android app with the ESP8266. You can take this example and modify it.

You could add multiple screens to the app, so you can other ESPs or add buttons to control more GPIOs.

For More Details: ESP8266 controlled with Android app (MIT App Inventor)

ESP8266 controlled with Android app (MIT App Inventor)

First, watch the video demonstration

Parts List

Flashing Your ESP with NodeMCU

Downloading ESPlorer IDE

Schematics (3.3V FTDI Programmer)