Skip to content

Latest commit

 

History

History
207 lines (152 loc) · 7.7 KB

how_to_make.md

File metadata and controls

207 lines (152 loc) · 7.7 KB

How to make a WatchDuino 2

Bill of materials

You'll need the following in order to build a WatchDuino 2:

  • 1 × Arduino mini pro 2 8Mhz 3.3v
  • 1 × LIPO battery 240mah
  • 1 × 0.96” I2C 128X64 OLED
  • 4 × 3x6x2.5mm Push Button 2 Pin
  • 1 × 0.06A Flat Micro Vibrator Motor
  • 1 × TP4056 Micro USB LIPO charger (5V, 1A) External charger
  • 1 × HM-10 Bluetooth 4.0 Uart Transceiver
  • 1 × 12mm piezo buzzer speaker
  • 1 × Micro USB LIPO charger External charger (optional)

See this post for a handy shopping list, with links to the products on Aliexpress.

Since the componenents are really cheap (altogether they total roughly 10USD if bought on Aliexpress), it's probably is a good idea to stock yourself with at least a couple duplicates of each. Sometimes you can break them while soldering!

Loading the WatchDuino firmware in the Arduino Mini

Before you even start building, it is convenient to load the WatchDuino firmware into the Arduino Mini. You can also do this at the end, but if you do it now you'll be able to try the components as you go along.

These are the steps you need to follow:

  1. To install the firmware on a device you'll need the Arduino SDK and IDE. You can download the latest bundle for your platform on the official website, for free. Unzip the package to any location of your choice. Remember this location, because this will be the Arduino SDK, everytime we refer to it. Open the arduino executable inside the SDK folder to run the IDE.

  2. Copy all the folders inside the libraries folder in this repo into the libraries folder of your Arduino SDK. These are dependencies the WatchDuino code needs to compile.

  3. On the Arduino IDE, click on File->Open. Navigate to where you cloned the WatchDuino repository, and pick the watch/watch.ino file to open. All of the WatchDuino files should now have been loaded in the IDE.

  4. On the IDE now go to Tools->Board and pick Arduino Pro or Pro Mini. Then pick Processor:ATMega328 (3.3V, 8Mhz). This step is needed because the IDE needs to know the microcontroller that we are using, in order to apply the correct compilation options.

  5. After all this, you should be able to compile the code. On the IDE, click on the Verify button (the first icon in the toolbar, showing a tick). After a minute it should be done without errors.

  6. You are ready now to upload the code into your Arduino Mini. Plug the TTL adapter module to your Arduino, and then connect it to your PC via USB. Some LEDS on the Arduino should turn on.

  7. Then go to Tools->Port, and you should be able to see something in there (in my case it's '/dev/ttyUSB0', but this will likely be different depending on your OS. It's essentially an identifier for your USB port where your Arduino is plugged). If you see Tools->Port greyed out, it's because you are not running the IDE with sufficient permissions. If you are on Linux try running the program with a superuser (eg. sudo on Ubuntu).

  8. After that, click on the Upload button (the second icon in the toolbar, showing a right pointing arrow). The Arduino Mini should now be loaded with the WatchDuino firmware.

Mounting a prototype on a breadboard

Before you go and build the real thing, it's advisable that you build a prototype version on a breadboard. This way you can test that the code is correctly loaded into the Arduino board, and that you understood all the connections in the schematic right.

The schematic can be found in the schema folder of this repo, you should see an .fzz file in there. You can use the Fritzing software to open this file, and it'll show you a detailed view of the components connected together, which you can zoom and hightlight the connections in.

After you've successfully flashed the Arduino with the firmware, leave it connected to the USB, and place it on the breadboard. Then:

  • Place the buzzer (on pins D12, and GND). You should hear a "beep" if you reset the Arduino.
  • Place the screen (pins A4, A5, GND, VCC). You should see the WatchDuino interface if you reset the Arduino.
  • Place the buttons (pins D2, D4, D5, D6). You should be able to use them to navigate through the menus.
  • Place the bluetooth module (pins D9, D10, VCC and GND). If your bluetooth module has any leds, you should see one of them blinking intermitently. This is because it hasn't been paired yet. If you pair to the companion phone app it should become fixed.

At this point, you have a fully functional (albeit not wearable) WatchDuino. Have a test around the interface, install the companion app on your phone, pair the two and check that the bluetooth connection works smoothly. Refer to the comapanion app repo for instructions on how to get it.

Soldering a wearable version

Note: Before you assemble all these modules, it's highly recommended to test them separately (for instance, by building the breadboard prototype first).

We'll show you how to solder the components together so that they can fit into the WatchDuino case we've designed. You can 3D print the case yourself, or using any on-demand 3D printing service, such as Shapeways.

What you'll need:

  • All of the WatchDuino 2 components
  • WatchDuino 2 case
  • Soldering gun
  • Glue gun
  • Stripboard

Solder BLE and Arduino Mini together

For a space-efficient filt, solder the BLE module directly to the back of the Arduino. You only need 4 pins here:

BLE Arduino
TX D11
RX D10
VCC 3.3
GND GND

Glue the microbuttons to the screen

We need the buttons to be next to the screen. The easiest way to achieve this is actually to glue them in place first, and then solder them.

Solder the pins and the screen

The goal now is to connect the Arduino+BLE to the Screen+Buttons.

To make this job easier, we soldered the screen and button pins to a middle PCB board, made from a coutout from a standard stripboard.

Screenboard Arduino
SCL A5
SDA A4
VCC 3.3
GND GND
RIGHT BT D4
LEFT BT D5
SELECT BT D6
MENU BT D2

Reminder: The screen uses 2 analog pins (A4 and A5) which are in the middle of the Arduino Mini board.

Place the components on their place in the strap before soldering, so that you know they will fit afterwards. Once you finished, you can test the prototype by connecting the Arduino Mini to your computer (by using the USB-TTL adaptor).

Buzzer and Vibrator

Connect these two additional pieces to the following pins:

components Arduino
BUZZER D11
VIBRATOR D12

They fit into their own link in the strap.

Battery and changer

Having a rechargeable battery is what will actually make your WatchDuino portable. For ours we use a 240mAh battery, and a USB LiPo charcher, both connected to the VCC and GND pins on the Arduino. Each of them placed on a separate link on the strap.

Optionally, you could remove the LiPo charger from the model, and keep 2 pins to charge the battery using an external LiPo charger (and sell it separately to become a millionarie, like the cool companies do).

Enjoy your WatchDuino 2

Now you have a fully assembled WatchDuino 2! Place everything in their place in the case, put it on your wrist, and go have fun with it.