Line Following - Obstacle Avoiding - Drawing Robot

(ESP8266 Dual DC Motor Controller Board)

Hi everyone! In this project, I designed a board that includes the ESP8266 (ESP-12F) WiFi module, allowing you to control sensors such as HC-SR04 ultrasonic and infrared (IR), a servo and dual DC motors (DRV8848). To test the development board, we're going to build a small but fun 3D robot and control it, let's get started!

Supplies

• ESP-12F DRV8848 Driver Development Board
• HC-SR04 Ultrasonic Sensor
• Infrared (IR) Sensor
• Micro Servo Motor
• Dual Gear DC Motors (600RPM 6V)
• 3D Parts (SMARS Modular Robot)
• 11.1V 3S Lipo Battery
• Pliers
• Some Filament
• Two each with a bolt, nut and washer
• Water-Based Acrylic Paint for 3D Parts (Optional)

3D Parts of the Robot Chassis

Followers will remember, I previously designed a board based on Atmega328 with L293D motor driver and used a 3D robot chassis. I will use the same chassis in this project, but the parts of the chassis are very deformed, so I used PCBWay's 3D printing service when ordering the printed circuit board.

One of the best things about PCBWay is that it provides many services such as PCB, stencil, 3D and CNC that you need while doing a project. The new 3D parts were produced with SLA printing. A type of resin material is used thus providing dimensional accuracy, smooth surface and excellent detail. The previous 3D parts are FDM printing. PLA material is used for low-cost, non-functional prototyping. You can see the difference in quality between the parts when the models are compared.

Before we move on to the printed circuit board, let's paint the 3D parts black with acrylic spray paint. Thus, there will be color harmony with other additional 3D parts of the robot. For this you will need a box and water-based acrylic paint. We place the 3D parts to be painted in the box and apply the spray paint as a thin layer on the part surfaces.

Printed Circuit Board - ESP-12F DRV8848 Driver Board

Until the 3D parts are dry, let's take a closer look at the printed circuit board. Printed circuit boards are preferred for long-term use, stable and more durable electronic circuit prototypes.

Some "surface mount device" components are preferred in this board, this affects the size and cost of the board design. For the assembly of SMD components, a stencil is generally preferred. Solder stencils help to accurately apply solder paste in position of components and the stencil is usually ordered with the printed circuit board. 

The Process of Applying Solder Paste Using a Stencil

Solder stencils help to accurately apply solder paste in position of components. The process of applying solder paste using a stencil is simple, first fix the printed circuit board and place the stencil to match the board.

Then put some solder paste on the stencil with the help of a spoon and spread it with a spatula. 

Here are some materials you need for this step:

• Solder Paste
• Masking Tape
• Solder Paste Spreader

Placement of Components on PCB and Soldering Process

After applying the solder paste, it is necessary to place the required components on the board. Where to place these components is usually indicated by a designator or footprint reference. These references are used as part of the PCB design and ensure the correct placement of components. Designator shows what a component is and where it is located.

After the components are placed on the solder pads with the help of solder paste, the soldering process begins. Soldering is usually done with a hot plate machine or a hand soldering iron. The soldering machine heats and melts the solder paste and fixes the components in place. After the soldering is complete, the components are completely fixed in place when the solder paste has cooled. 

After soldering a few more components, the board will be complete. These components are a few headers and resistor. It can be easily soldered with a soldering iron.

Thanks for your interest, you can take a look at this project as an article on Instructables