IOT WALLET (smart Wallet with Firebeetle ESP32)

Description

If you invested some money in cryptocurrencies, you probably already know that they are highly volatile. They change overnight and you never know now much 'real' money you still have in your wallet.
So how do you track these assets and know their current value? You can work with some spreadsheets and update them regularly. Or you can create your own gadget to check these values for you: an IoT wallet!
For this project, I worked on the Google spreadsheet to track my assets and update their values for a particular currency, based on the ticker values retrieved from the Internet. This spreadsheet is accessible from an ESP32 using and Wi-Fi connection, and a summary is shown on an OLED display. A 3D printer was used to create a wallet, in which I embedded some electronic components to create my first IoT wallet prototype.
And that's not all! Why not add a clock synchronized with the internet and a step pedometer in the same gadget? In this tutorial I'll show you how

Details

There are several ways to use this tutorial. You can use it to:

- Learn how to track and update your asset values for a particular currency using a Google spreadsheet;

- Program an ESP32 using the Arduino IDE;

- Read values from a Google spreadsheet using an ESP32 device;

- Learn to 3d print using flexible filaments;

- Practice your electronics and soldering skills, etc;

You can use part of this tutorial to create your own gadgets or follow it to the end and produce your own wallet.

This tutorial is divided as follows:

Step	Subject	Topics
1	Tools and materials	Tools and materials used in this project
2-3	3D printing	How to 3D model and 3D print the gadget
4-5	Electronics	How to wire up the circuits
6-7	Google Spreadsheet	How to create a Google Spreadsheet an share it with your gadget
8-12	Coding	How to program a ESP32 using Arduino IDE

There are some awesome tutorials on how to track the prices of crypto currencies. This one served as a inspiration for this project: https://www.instructables.com/id/Simple-10-Crypto-Currency-Display/

Liked that projects? Please consider supporting my future projects with a small Bitcoin donation! :D BTC Deposit Address: 1FiWFYSjRaL7sLdr5wr6h86QkMA6pQxkXJ

For this project, the following tools were used:

3D printer. I used it to print my wallet and produce a case for the electronics (with regular PLA filament). You can find some inexpesive 3D printers online that will work just fine for this project (link).
1.75mm PLA filament (link / link / link). I used rigid white and blue PLA filament for printing the case where the electronics are encased and protected. This way they won't get crushed if I sit with on my wallet, or if it accidenty falls on the floor.
Solder iron and wire. I needed it to solder some wires between the electronic components, as you'll se later.
Super glue. The 3D design was printed in different parts. I used some super glue to stick them together.

I used the following hardware parts for my project:

Firebeetle ESP32 dev board (link). Firebeetle ESP32 board is really easy to use and program using Arduino IDE. It has built-in Bluetooth and Wi-Fi modules, so you can use it in a variaty of projects. It has a connector for a 3.7V battery, which was really usefull for assembling this project. I has also a built-in battery charger. It will recharge the battery when connected to an USB plug. You can also use other ESP32 based boards (link / link), or ESP8266 ones (link / link / link) if you wish. Deppending on the board you choose, it would be a little more difficult to connect and recharge the battery. The dimensions of the case will also need to be verified.
OLED display (link / link). It was connected to the ESP board, for displaying the values obtained from Google Spreadsheet.
GY-521 accelerometer (link / link). It was used as a step counter.
3.7V battery (link / link). I used to power the whole circuit.
Wires.
Micro USB cable.
M2x6mm bolts (x9)
M2x1.5mm nuts (x5)

The links above are only a suggestion of where you can find the items used in this tutorial (and maybe support my future tutorials). Feel free to search for them elsewhere and buy at your favorite local or online store.

As it was said before, some ESP dev boards won't have a built-in battery connector (and charger). In that case, you'll need an external battery charging module (a TP4056 (link / link), for instance). It will possibly require a mini USB cable for the connection between the charger and an USB port. Did you know you can buy a Anet A8 for only $155.99? Get yours at Gearbest:http://bit.ly/2kqVOdO

Components

Build Instructions

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1

3D Modeling

In this step I present how the wallet was designed for 3D printing using flexible filaments. I also introduce the step-by-step involved in design of the case where electronic components are protected.

If you're only interested in printing your own wallet, skip to the next step, where you can find finished stl files. If you are not interested in 3D printing, skip a few more steps. If you are interested in 3D printing, but do not have a printer, why not buy one? Did you know that it is possible to buy a 3D printer for only 359.99 USD? Click HERE!

The wallet was designed to hold three cards and some electronics (microcontroller, display, and battery). An elastic might be used for holding additional doccuments and maybe some paper money. It was desgined using Fusion 360 CAD software.

The model is composed of only two different part: cap, body. I'll detail how I drawed each of this parts, in case you want to replicate it on your own design.

1. Components

First I made a simple representation of each component used on my wallet. They don't have to be very detailed, but should have the right measurements. This was important to help define the relative position of each component inside the wallet. This way, I had to create a model for the ESP32 Firebeetle, OLED display, battery, and of a standard credit card.

2. Arrange the components

With a model of each component, you can play with their position and choose the best position for each one. I wanted to create a gadget as slim and as small as possible. This way, I tried to organize the devices to use a footprint close to a standard credit card area.

3. Drawing the sketches

After choosing the location of the instruments, the sketches were drawn and the structure was extruded.

The model was divided in two parts: the body of the wallet and the front cover. The body has holes for the bolts for the installation of the electronics. It also has hole that allows connecting an USB cable to the microcontroller (for uploading a code or charging the battery). It was were designed usin 0,8 mm walls, and have space for 3 cards. The front conver is glued to the wallet, protecting the electronics. It also has a hole for the touch button.
2
3D Printing
You can download all the stl files on the following websites:

https://www.thingiverse.com/thing:2886806

https://pinshape.com/items/45150-3d-printed-iot-sm...

The whole print took me around 2h30, printed with 0.2 mm resolution and 10% infill.

This is a experimental prototype. Notice that it was designed for a given ESP32 dev board model (the ESP32 Firebbetle). If you want to use a different model, please send a comment and I can see if it's possible to change model dimensions to fit your needs.

If you don't have a 3D printer, here are some things you can do:
- Ask a friend to print it for you;
- Find a hacker/maker space nearby. The parts used in this model can be printed quickly (around 3 hours). Some hacker/maker spaces will only charge your for the materials used;
- Buy your own 3D printer. You can find the Creality3D CR10 for only $359.99. Use the coupon code cr10mini3d at Gearbest and get yours: http://bit.ly/2JIUVrf
- Improvise! You can try to assemble a structure without 3D printed parts.
Interested in purchasing a DIY Kit? If enough people are interested, I might be offering a DIY kits on Tindie.com. If you would like one, send me a message.
3
Wiring Up the Circuits
The circuit uses four main components:
1. Firebeetle ESP32. This development board already comes with WiFi module, and a connector for a 3.7V battery. It can also charge the battery if you connect USB cable is connected.
I soldered the wires before putting the electronics inside the case. The components were connected as shown in the schematics.

OLED display:
- Display Vcc pin -> ESP32 3V3 pin
- Display Gnd pin -> ESP32 Gnd pin
- Display SDA pin -> ESP32 D3 pin
- Display SCL pin -> ESP32 D5 pin
GY-521 (accelerometer):
- GY-521 Vcc pin -> ESP32 3V3 pin
- GY-521 Gnd pin -> ESP32 Gnd pin
- GY-521 SDA pin -> ESP32 SDA pin
- GY-521 SCL pin -> ESP32 SCL pin
The accelerometer isn't mandatory. You might even remove it to save some battery, if you wish.