Gmailbox

2018-10-16 | By Adafruit Industries

License: See Original Project 3D Printing Adafruit Feather

Courtesy of Adafruit

Guide by Brent Rubell

Introduction

Ahhh, the charms of suburbia, mowing the lawn, white picket fences, running barefoot to the mailbox to see if the postal worker already dropped by. Sometimes we wax nostalgic for our childhood. Maybe we’ve become de-sensitized to the constant work email notification pop-ups on our smartphones.

Wouldn’t it be nice to get a friendlier heads up? Do you ever miss the old-school “You’ve got mail!” sound from your old AOL email client?

We're going to make a small mailbox to sit on your desk and notify you about incoming emails. When a new email is received, it raises a flag and gently lowers it back down.

It's a fun, easy, introductory project to the Internet-of-Things by making things move using Adafruit IO with IFTTT.

Parts

You'll need the following parts to complete this guide.

Supplies

Wire and handy supplies for soldering.

1 x Silicone Cover Stranded-Core Wire
1 x Solder Wire

Tools

To build your Gmailbox, you'll need access to the following tools. Don't have something listed? Pick it up from the Adafruit shop.

Hardware

You'll need some screws and nuts to secure the parts together. We have them linked here but you can source them from your local hardware supplier.

2 x M2 x 12mm Machine Screws
2 x M2 Hex Nuts
4 x M2.5 x 6mm Machine Screws
2 x M3 x 8mm Machine Screws
2 x M3 Hex Nuts

3D Printing the Mailbox

Gmailbox Parts

There are six 3D-printed parts which make up the Gmailbox:

Mailbox Bottom
Mailbox Top
Servo Holder
Mailbox Cover (Front)
Mailbox Cover (Back, Micro-USB cutout)

What if I don't have a 3D Printer?

Not to worry! You can use a 3D printing service such as 3DHubs or MakeXYZ to have a local 3D printer operator 3D print and ship parts to you. This is a great way to get your parts 3D printed by local makers. You could also try checking out your local Library or search for a Maker Space.

Slicer Settings for Cura

Layer height: 0.2mm
Line Width: 0.38mm
Wall Thickness: 2 line count
Infill: 20% triangle pattern
Print Speed: 60mm/s
Extruder/Bed Temps: 220c / 60c
Supports: Nope!

CAD Assembly

This animation demonstrates how the parts fit together. The assembly was designed for 3D printing and optimized to print without any supports. The front cover hinges onto the case while the back cover snap fits shut. The bottom cover is clamped to the case. The STL files are oriented to print "As-is".

Design Source Files

The enclosure assembly was designed in Fusion 360. This can be downloaded in different formats like STEP, SAT and more. Electronic components like the board, displays, connectors and more can be downloaded from our Fusion 360 CAD parts github repo.

If you need another format for your printer, use the following link:

Download Files on GibHub

Fusion 360 Source

Download STLs on Thingiverse

Tap Mounting Holes

The mounting holes in the bottom cover and case will need to be tapped using an M2 and M2.5 tap tools. This will create threads inside the mounting holes to allow precise fastening.

Making Threads

A tapping tool has coarse and sharp edges that are designed to scope out excess material. A tap handle is used instead of a drill to minimize friction caused by rotational speed (PLA plastic melts!). Slowly twisting the handle produces better results. Try to be as straight as possible when tapping holes.

Tap Holes in Case

The two mounting holes on the side of the case feature geometry optimized for 3D printing. The part is printed vertically and produces holes that have slightly tighter tolerances. Use an M2 tapping tool to create threads in the mounting holes.

Tap Plate

The two mounting holes in the flat plate are also M2 sized and slightly tighter. These were also tapped. The M2 size tapping tool has a very small shank that did not fit my tap handle – So I designed and 3D printed one!

Install Plate

Place the plate over the side of the case with the ovular opening. Line up the mounting holes. Insert and fasten two M2 x 12mm flat head machine screws.

Mounting Screws

Continue to fasten the screws until the shank is about halfway through the case. Hold the parts together while fastening.

Mailbox Parts Assembly

Once all of the parts are printed, a dry fit test will ensure everything fits properly or may need a bit of sanding. Start with the case and back cover parts first. Press the back cover onto the end of the case with the flat side. Fit the lip over the case on one side and press fit the other side to snap the edges together. Insert the bottom cover in between the rail of the case and slide into the back cover. Fit the nubs from the front cover over the dimples in the lower corners of the case.

Putting it Together

Wiring

Make the following connections between the servo and the Feather HUZZAH:

Servo Yellow to Feather Huzzah Digital Pin 14
Servo Brown to Feather Huzzah GND Pin
Servo Red to Feather Huzzah 3V Pin

Not comfortable with soldering? You can order a Feather HUZZAH ESP8266 with stacking headers pre-soldered, and use male/male jumper cables to connect the servo to your Feather HUZZAH.

Premium Male/Male Jumper Wires - 40 x 3" (75mm)

Assembly

Assembly

Install HUZZAH to Mount

Use two M2.5 x 4mm flat head machine screws to secure the Adafruit Feather HUZZAH to the bottom cover part. Place the PCB over the standoffs and line up the mounting holes. Fastening screws into standoffs work best when tapped and threaded. USB port should be facing the edge of the mount.

Install HUZZAH to Mount

Installed HUZZAH

Flat head machine screws had a tapered screw head. This is nice for low clearance mount holes. The mounting holes on near the antenna have a slightly smaller diameter and should be tapped when intending to secure all four mount holes. Be cautious not to over tighten or that could damage the antenna.

Install Servo

Grab the servo and orient to match the mounting holes on the 3d printed case. Insert the servo, shaft first, through the opening in between the mounting holes. Press firmly to fit through the wall. If it's too tight to push through, loosen the opening by filing edge with filing tool or sand paper.

Secure Servo

Insert and fasten two M2 x 12mm machine screws on the outside of the case through the mounting tabs in the micro servo. Fasten until fully tighten. The flag mount plate has chamfered holes to allow flat head screws to be flush with the surface.

Flag Servo Horn

Use the single arm servo horn that came with your submicro servo. Superglue will bond the two surfaces together. Place the servo horn over the flag and line up the mounting holes. Glue and set dry. Use one of the small screws to secure the flag to the servo.

Install Flag

Line up the servo horn with the splines on the sub-micro servo. The position of the flag will need to be tweaked and adjusted to properly line up with the expected angles of degree.

Secure Flag

Secure Flag

Once the position is figured out, insert the small screw through the flag. Fasten the screw through the flag until the tip pokes through the servo horn. Then, press fit the servo horn onto the splines. Continue to fasten the screw and hold onto the flag until fully tightened.

Building The Mailbox

Building The Mailbox

Now that we have our parts secured and mounted, we can put everything together!

Building The Mailbox

Back Cover

Start with the back cover. Line up the curve with the case and fit one side of the lip onto the indentation on the case. While holding the case, firmly press the other side of the lip on the back cover. The cover should snap fit and lock into place.

Bottom Cover

Line up the bottom cover so the USB port on the HUZZAH is facing the back cover. Insert one side of the railing on the case to the lip on the bottom case. Firmly press down on the other side to snap it onto the rail of the case. Slide the bottom cover up and firmly press to wedge it into the back cover.

Front Cover

Fit one side of the tab over the dimple on the case. Pinch the ends of the case together to allow clearance for fitting the other tab. Clip the tab over the case and onto the dimple to secure the hinge.

Adafruit IO Setup

If you do not already have an Adafruit IO account set up, head over to io.adafruit.com to link your Adafruit.com account to Adafruit IO.

We need to create a new feed to hold data for the incoming emails. Navigate to the feeds page on Adafruit IO. Then click actions -> create new feed, and name this feed gmail.

If you do not already know how to create a feed, head over to Adafruit IO Basics: Feeds.

We're also going to need our Adafruit IO username and active key. Navigate to your profile and click the View AIO Key button to retrieve them. Write them down in a safe place, we'll need them for later.

Now that Adafruit IO is all set up, let's link IFTTT to your Gmail account.

IFTTT Setup

If This Then That is an internet service which can listen to services on the internet (such as a new tweet) and trigger physical device actions.

Once you're signed up and logged into IFTTT, navigate to the Create page to create your applet and click the +this button:

When prompted to Choose a Service, use the search-bar to look for Gmail

Next, we'll need to choose a trigger. This is an event which occurs in Gmail that's used to cause our action ("then that") to occur. We'll need to retrieve any email which comes into our inbox.

Select Any new email in inbox

Once the trigger is selected, you'll be taken back to the If Then That page. This time, click on +that

On Step 4, search for Adafruit in the search bar and select Send data to Adafruit IO on the Choose Action page

On Step 5, select gmail as the Feed Name. On the Data to Save field, click Add ingredient and then select ReceivedAt from the dropdown.

Note: While we could select any data element from the gmail feed, we don't want to leak important information such as the sender or subject. So, we'll send date/time data.

Review the applet's settings to make sure they're correct. Then, click finish.

Next, we're going to set up our Arduino for programming.

Arduino Setup

You should first go through the setup guide associated with your selected hardware, and make sure you have internet connectivity before continuing. The following links will take you to the guides for your selected platform:

Installing Libraries

If you haven't installed our Adafruit IO Arduino Library or if you have an older version of this library, you will need to make sure you install version 2.7.15 of the Adafruit IO Arduino library installed before continuing. It is available from the Arduino library manager so we recommend using that.

Not sure how to use the Library Manager? We have a great learn guide about installing libraries:

From the Arduino IDE, open the Library Manager

Enter Adafruit MQTT into the search box, and click Install on the Adafruit MQTT library option to install version 0.20.2 or higher.

Enter ArduinoHttpClient into the search box, and click Install on the ArduinoHttpClient library option to install version 0.3.0 or higher.

Type Adafruit IO Arduino into the search bar to search for the library. Click Install to install version 2.4.15 or higher.

The code for this example is contained within the Adafruit IO Arduino Library. Open the adafruitio_23_ifttt example from within the Arduino IDE: File->Examples->Adafruit IO Arduino->adafruitio_23_ifttt

Next, we'll perform the network configuration required for this sketch.

Arduino Network Config

To configure the network settings, click on the config.h tab in the sketch. You will need to set your Adafruit IO username in the IO_USERNAME define, and your Adafruit IO key in the IO_KEY define.

WiFi Config

WiFi is enabled by default in config.h so if you are using one of the supported WiFi boards, you will only need to modify the WIFI_SSID and WIFI_PASS options in the config.h tab.

FONA Config

If you wish to use the FONA 32u4 Feather to connect to Adafruit IO, you will need to first comment out the WiFi support in config.h

Next, remove the comments from both of the FONA config lines in the FONA section of config.h to enable FONA support.

Ethernet Config

If you wish to use the Ethernet Wing to connect to Adafruit IO, you will need to first comment out the WiFi support in config.h

Next, remove the comments from both of the Ethernet config lines in the Ethernet section of config.h to enable Ethernet Wing support.

Next, we will look at how the example sketch works.

Code

Let's take a dive into the code that powers our Gmailbox. It's not too hard to understand and this code can serve as an introduction to Arduino and Adafruit IO.

We'll start by setting up the servo holding the flag. We wired the servo to the Feather HUZZAH's pin 14. If you need to change that, you can modify SERVO_PIN. We also define the flag's up and down positions (what angle to set the servo's maximum to) as FLAG_UP and FLAG_DOWN.

Want the servo's flag to be held up longer? You can do that by modifying the FLAG_DELAY variable.

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// pin used to control the servo
#define SERVO_PIN 14

// Flag's up position, in degrees
#define FLAG_UP 0

// Flag's down position, in degrees
#define FLAG_DOWN 180

// How long to hold the flag up, in seconds
#define FLAG_DELAY 2

Next, we're going to create an instance of the servo class and set up the gmail feed from Adafruit IO.

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Servo servo;
AdafruitIO_Feed *gmail_feed = io.feed("gmail");

The setup() function starts a serial connection, attaches the servo to SERVO_PIN, and attempts to connect to Adafruit IO. Then, it creates a message handler to listen to the gmail feed. We'll also write the servo to its' resting state (the FLAG_DOWN position).

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void setup() {

  // start the serial connection
  Serial.begin(115200);

  // wait for serial monitor to open
  while(! Serial);

  // tell the servo class which pin we are using
  servo.attach(SERVO_PIN);

  // connect to io.adafruit.com
  Serial.print("Connecting to Adafruit IO");
  io.connect();

  // set up a message handler for the 'servo' feed.
  // the handleMessage function (defined below)
  // will be called whenever a message is
  // received from adafruit io.
  gmail_feed->onMessage(handleMessage);

  // wait for a connection
  while(io.status() < AIO_CONNECTED) {
    Serial.print(".");
    delay(500);
  }

  // we are connected
  Serial.println();
  Serial.println(io.statusText());
  gmail_feed->get();

  // write flag to down position
  servo.write(FLAG_DOWN);

}

The loop() is empty aside from a call to io.run(), a function which keeps the client connected to io.adafruit.com.

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void loop() {
  io.run();
}

The handleMessage function is called whenever a new data value is received from the gmail feed on Adafruit IO. Inside this function, we'll print to the serial monitor that a new email has been received.

Then, we'll set the flag to the FLAG_UP position to indicate a new email has been received. We'll wait FLAG_DELAY seconds and then move the flag back down by writing the servo to its' FLAG_DOWN position.

The handleMessage function is called when the gmail feed is updated by Zapier or IFTTT.

When it receives new data from the gmail feed, it will write the servo to the flagUp position, waits a second so that you can see it, and moves it back to the flagDown position.

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void handleMessage(AdafruitIO_Data *data) {
  Serial.println("You've got mail!");
  servo.write(FLAG_UP);
  // wait FLAG_DELAY seconds
  delay(FLAG_DELAY * 1000);
  servo.write(FLAG_DOWN);
}

Testing out your Gmailbox

Upload the code to your Feather and open the Arduino Serial Monitor (Tools -> Serial Monitor).

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IFTTT Gmailbox
Connecting to Adafruit IO
..
Connected to Adafruit IO!

If you see the above, we're all set up to receive emails! Compose an email to yourself and send it! When the gmail feed receives new data, the serial monitor will print You've got mail!, put the flag up, and gently lower it.

Help - my Gmailbox isn't working!

I want to trigger my feed to show my friend/coworker the gmailbox, but don't want to clog my inbox

On the gmail feed page, you can click on the actions dropdown -> add data. You can enter any value, it doesn't matter for this project, and click create. You'll see a new data-point dropped onto the IO feed.

The flag on my mailbox isn't moving up and down

First, check that the feed is set up correctly. Visit your feed page for gmail and ensure your feed was updated when an email arrived.

If your feed did update, but the servo flag didn't move, there's a chance it was wired incorrectly. Re-read the wiring diagram on the Wiring and Assembly page. Make sure SERVO_PIN in the sketch is connected to the correct pin on your Feather HUZZAH.

My feed isn't updating when I get a new email

Check over your Zap or IFTTT Applet configuration. Make sure that the email is connected correctly.

Code

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// Adafruit IO IFTTT Example - Gmailbox
// Tutorial Link: https://learn.adafruit.com/gmailbox
//
// Adafruit invests time and resources providing this open source code.
// Please support Adafruit and open source hardware by purchasing
// products from Adafruit!
//
// Written by Brent Rubell for Adafruit Industries
// Copyright (c) 2018 Adafruit Industries
// Licensed under the MIT license.
//
// All text above must be included in any redistribution.

/************************** Configuration ***********************************/

// edit the config.h tab and enter your Adafruit IO credentials
// and any additional configuration needed for WiFi, cellular,
// or ethernet clients.
#include "config.h"

// Import Servo Libraries
#if defined(ARDUINO_ARCH_ESP32)
  // ESP32Servo Library (https://github.com/madhephaestus/ESP32Servo)
  // installation: library manager -> search -> "ESP32Servo"
  #include <ESP32Servo.h>
#else
  #include <Servo.h>
#endif

/************************ Example Starts Here *******************************/

// pin used to control the servo
#define SERVO_PIN 14

// Flag's up position, in degrees
#define FLAG_UP 0

// Flag's down position, in degrees
#define FLAG_DOWN 180

// How long to hold the flag up, in seconds
#define FLAG_DELAY 2

// create an instance of the servo class
Servo servo;

// set up the 'servo' feed
AdafruitIO_Feed *gmail_feed = io.feed("gmail");

void setup() {

  // start the serial connection
  Serial.begin(115200);

  // wait for serial monitor to open
  while(! Serial);

  Serial.print("IFTTT Gmailbox");

  // tell the servo class which pin we are using
  servo.attach(SERVO_PIN);

  // connect to io.adafruit.com
  Serial.print("Connecting to Adafruit IO");
  io.connect();

  // set up a message handler for the 'servo' feed.
  // the handleMessage function (defined below)
  // will be called whenever a message is
  // received from adafruit io.
  gmail_feed->onMessage(handleMessage);

  // wait for a connection
  while(io.status() < AIO_CONNECTED) {
    Serial.print(".");
    delay(500);
  }

  // we are connected
  Serial.println();
  Serial.println(io.statusText());
  gmail_feed->get();

  // write flag to down position
  servo.write(FLAG_DOWN);

}

void loop() {

  // io.run(); is required for all sketches.
  // it should always be present at the top of your loop
  // function. it keeps the client connected to
  // io.adafruit.com, and processes any incoming data.
  io.run();

}

// this function is called whenever a 'gmail' message
// is received from Adafruit IO. it was attached to
// the gmail feed in the setup() function above.
void handleMessage(AdafruitIO_Data *data) {

  Serial.println("You've got mail!");
  servo.write(FLAG_UP);
  // wait FLAG_DELAY seconds
  delay(FLAG_DELAY * 1000);
  servo.write(FLAG_DOWN);
}