After the last project:

Adafruit Huzzah WiFi

I wanted to have the device take input from a switch (which also came in the Starter kit).

Based on my existing projects I now created a configuration of:

Pin 4 = Red LED + Resistor (560 ohm)

Pin 5 = Green LED + resistor (560 ohm)

Pin 2 = button

Each of these lines then went to the GND pin.

For the code I found the following article which was a great help:

https://create.arduino.cc/projecthub/muhammad-aqib/arduino-button-tutorial-using-arduino-digitalread-function-08adb5

from which I adapted my own code at:

https://github.com/directorcia/Azure/blob/master/Iot/huzzah-button.c

So that when the button is pressed it swaps which LED is on like so:

Of course, it could be improved but I am still calling it a success as all I really wanted to do was incorporate input from an external source.

With all this now done, the next aim is to work out how to connect the device to Azure and get Azure capturing the input from the device and reporting it somehow.

My last IoT challenge was to get an

External flashing LED

working and the next was to get the Adafruit Huzzah with ESP8266 to connect to Wifi. To do that I found most the required code here:

https://learn.adafruit.com/adafruit-feather-huzzah-esp8266/using-arduino-ide#connecting-via-wifi

and I’ve put my code on my Github here:

https://github.com/directorcia/Azure/blob/master/Iot/huzzah-wifi.c

You’ll need to put in your own WiFi access point details at the top of the code to connect to your own environment.

This script uses a lot of commands like:

serial.println

which basically outputs text to a serial port. This allows much easier troubleshooting so you can see what is going on. To see this output you will however need a dedicated serial monitor console program. I started off using Putty:

https://putty.org/

which works great but upon reflection, I wanted to use something that was integrated directly into Visual Studio code. After some poking around I found this extension:

https://marketplace.visualstudio.com/items?itemName=ms-vscode.vscode-serial-monitor

which is from Microsoft and seems to do what I needed.

You can see the output from my code above in serial monitor. Always ensure you match the output port and baud rate in the serial monitor to the device you have (here COM3 and 115200). Configuring this is very easy with the serial monitor extension.

Without much alteration, I was able to take the initial code and easily connect to my network as well as the Internet. Once connected I could ping the Adafruit Huzzah with ESP8266 from another PC in the network. A pretty painless exercise. Nice that things are becoming a little easier now I’m becoming familiar with this stuff.

So far, all I’ve done is use the Adafruit Huzzah with ESP8266 for output. Next, I’ll be to start taking simple input into the device by reading something like a button press and then taking action on that.

Stay tuned for details on that soon.

My first IoT project was to get the on board LED flashing which I achieved here:

Not as easy as IoT

With that accomplished, I now wanted to get an external LED flashing.

I firstly needed to pick a pin on the Adafruit device to control the output on.

I chose the third in from the bottom on the right which is PIN 2.

Next, I needed to work out the maximum output voltage for the Adafruit Feather Huzzah, which turns out to be 3.3 Volts. I also noted the following from the pin output specifications as well:

“be aware the maximum current drawn per pin is 12mA. 6mA recommended”

I also needed to take into account the voltage drop that would occur across the LED, which is around 0.7V. So the voltage for my calculation was now:

3.3V – 0.7V = 2.3V

To work out what resistor I needed to place in the circuit I used the good ole V= IR.

V=IR

R = V/I

R = 2.3 / 0.006

R = 433 ohms

I double checked my logic at:

http://www.anycalculator.com/ohmslaw.htm

I then went through the:

Microsoft Azure IoT Starter Kit w/ Adafruit Feather HUZZAH

I had bought to see what resistors were included. In there I found a 560 ohm resistor. If you need to check your resistor markings like I did, you can use:

https://byjus.com/physics/resistor-colour-codes/

to help discern what you have.

A 560 ohm resistor would means my current would be:

I = V / R

I = 2.3 / 560

I = 4.1 milliamps (well below the 6 milliamp recommendation)

All I needed now was to find the ground for the Adafruit

which turned out to be the fourth pin from the top on the left.

I therefore wired up the output from pin 2 on the Adafruit, through the LED, through the resistor and then to ground, completing the circuit.

Now for the code to make it flash.

#include <Arduino.h>

int LED_Pin = 2;

int status = 1;

void setup(){

pinMode(LED_Pin, OUTPUT);

}

void loop() {

  // put your main code here, to run repeatedly:

if (status) {

digitalWrite(LED_Pin, HIGH);

  } else {

digitalWrite(LED_Pin, LOW);

  }

status = 1-status;

delay (1000);

}

which is basically the same as before, except the LED_pin now is set to 2. The code is at:

https://github.com/directorcia/Azure/blob/master/Iot/huzzah-ext-flash-led.c

Using PlatformIO IDE I uploaded my code to the Adafruit and after a few minutes was greeted by:

Magic eh?

Sure it’s simple but it’s another step along my IoT journey.