How to make simple Arduino Phone

Today we will make a programmable mobile phone for beginners to learn about microcontrollers.

A simple way to get started with Arduino.

Objectives:

1. Programing basic features
2. Communicate and display LCD screen with Arduino
3. Communicate and get data from SIM module to make calls and send messages
4. Use matrix keys
5. Schematic circuit power and charging for battery
6. Learn how to design PCB circuit

Supplies:

1. Arduino Pro Mini 3V3: Here
2. SIM800C or A7680C module: Here
3. Nokia 5110 LCD display: Here
4. 4x4 matrix keypad: Here
5. TP4056 charging circuit: Here
6. MT3608 3V3 voltage regulator circuit: Here
7. CH340 code loading circuit: Here
8. Need some resistors, wires and test board,..

Overview:

Power block: utilize a slim 3.7V power battery for mobile applications. A universal charging module like the TP4056 is required to charge and manage the battery voltage. Additionally, a 3V3 power supply is necessary for the entire circuit to function. We employ the MT3608 IC, a type of boost converter IC, to elevate the voltage from the battery to 3V3. It's important to note that the battery voltage will fluctuate from 3.2V when low to 4.2V when fully charged.

MicroController block: Implement the ATMEGA328P 3V3 IC from Arduino Pro Mini or Arduino Nano, which is very user-friendly for beginners starting with programming.

SIM block: Incorporate the SIM800C module to connect to the GSM network for making calls and sending messages. I selected this SIM module primarily because it is very affordable and easy to solder manually. However, in several countries, 2G networks have been phased out, but a solution exists without needing to change the hardware: using SIMCOM's 4G module, the A7680C, which has a pinout that is fully compatible for replacement.

Display block: Utilize the Nokia 5110 LCD display, giving this phone a nostalgic look reminiscent of Nokia phones from the 2000s :v. But that's not the main point! The key aspect is that it is readily available, inexpensive, and simple to program. An OLED screen can also be used for enhanced display quality.

IO block: Employ a 4x4 matrix keypad for data entry and device control.

The buzzer and LED light can function as a flashlight and provide notifications for incoming calls.

I have a concept where we can substitute the LED light with an infrared light, allowing us to input the IR command learned from a television remote or air conditioner. This would enable our phone to function as a remote control. There are countless ideas you can explore with this.

Avoid trying to connect everything at once, as it can become overwhelming. However, it's not overly complicated. Just read the datasheet and library, and follow the instructions step by step!

Like all developers in the world, the first thing they do to program is “Hello World”. We will also have the first thing for every microcontroller is “Blink Led”.

Use the code uploader and open the Arduino IDE to create the first project for Arduino Pro Mini.

Link instructions and example code here:

1. How to program Arduino Pro Mini using CH340 Module: Link

Link instructions and example code here:

1. Send Receive SMS & Call with SIM800L GSM Module & Arduino: Link

Utilize libraries and tools to showcase whatever you display on this screen, such as logos, images, and news updates, to customize your phone to your liking.

This part of the project is the most time-consuming. It's crucial to have a thorough understanding of the LCD display to program it according to your preferences.

Connect Arduino with Module LCD5110:

Link instructions and example code here:

1. Interface Nokia 5110 Graphic LCD Display with Arduino: Link
2. Menu on a Nokia 5110 LCD Display with Arduinio Tutorial: Link

Use a 4X4 keypad with 16 buttons and 8 pins on the microcontroller. Programing to receive buttons to perform functions or receive data such as numbers to call, text messages.

Connect 4X4 Keypad to Arduino: C1-14 to A0-A3 and H1-H4 to Pin 9-12.

Link instructions and example code here:

1. Interfacing Arduino with 4×4 Matrix: Link

Add a battery and a charging module for it.

Assembling everything into a mini box, we now have a basic mobile version 1.0.

Done?

No, of course not. We need this project to be professional and easy to develop for any newbie.

Start designing everything with professional design software such as Altium Designer, Kicad, Eagle, EasyEDA,...

Here I use Altium Designer Software: Link

Build a schematic from the components, modules used before and edit to suit the requirements. You may need to look at the datasheets from the manufacturer to know how to build a standard circuit.

Import the PCB and start the layout.

Arrange the components and place them in the appropriate positions, proceed to wire. Follow the rules for 2-layer circuits and the PCB manufacturer of your choice.

Place the PCB oder: JLCPCB - Link

The Gerber file I left below can be ready to send to the PCB manufacturer. Send them and they will make pcb for you, can choose the color you like: black, white, blue,...

Choose Base Material FR-4, 2 Layers, PCB Qty 5, PCB Thickness 1.6mm, PCB Color,...

Add items to your cart, proceed to checkout, and then wait.

Download Gerber File: Link here

Below is the schematic diagram I have created.

First, ensure that all the components listed in the Excel BOM are prepared, along with the soldering iron, heat blower, and all required tools.

Begin by soldering and testing the circuit sample, where your determination, alongside you soldering expertise, is crucial. We're working with tiny 0603 components, so if the budget allows, you could use a stencil to apply solder paste. After then using the heat table or heat blower with temperature about 240 - 350 °C to solder components. However, I believe it's entirely possible to solder by hand using soldering Iron. It's a time-intensive process, but it's also quite interesting.

Download Bill of Material (BOM): Link

Examine the solder joints once again. Prior to connecting the power, it is essential to test the power source to ensure it complies with the 3V3 standard, as any deviation could potentially harm the microcontroller.

Remove the 0R resistor from the 3V3 power supply, install the battery, and perform a test to confirm that the TP4056 battery charger functions properly with 5V power from the MicroUSB port. Utilize a multimeter to measure the battery voltage along with other voltages. Subsequently, inspect the MT3608 block, assessing both the input and output to ensure they are at the appropriate 3V3 level; if they are not, recalibration of the Feedback resistor may be necessary. Furthermore, it is vital to measure the circuit to prevent possible short circuits resulting from PCB or soldering issues. After completing these verifications, reconnect the 0R resistor, and the phone should become operational.

Main Code