POWAR + WIO Terminal IoT Board

POWAR is a DIY Low-Cost climate simulator to grow food under future predicted weather. It runs on the Seeed Studio WIO terminal and uses Grove Sensors, Grove Relays and Grove Mosfets to sense and actuate on its interior. This new version is now being produced by Seeed Fusion, the Seeed Studio PCB manufacturing department, and soon will be delivered at our home to test it.

(CHECK HACKSTER DOCUMENTATION)

The previous versions of POWAR used to have tailor-made electronics, and home fabricated boards for sensors, actuators and electrical connections. After we discovered the WIO terminal, our prototype evolves a lot, but we were still struggling with the number of sensors and actuators we needed to connect, and also with the power management system which we need to be able to provide different outputs of 5V and 12V so that it can control actuators of different ranges of voltage.

We are manufacturing this board as a collaboration with Seeed Fusion, the One-Stop Shop for Agile manufacturing and Hardware Customization, from Seeed Studio, which lets you accelerate your product time-to-market:

https://www.seeedstudio.com/fusion.html

They offered to produce our prototype for free, since it is going to be a tool that will be used on the Seeed Studio WIO terminal for our POWAR project.

WIO Terminal pinouts:

The Seeed Studio WIO Terminal is a compact development board designed for rapid prototyping and creating interactive projects. It features a built-in display, various sensors, and extensive connectivity options.

Here is a description of the pinouts available on the WIO Terminal:

• Analog Pins: The WIO Terminal has six analogue pins labelled A0 to A5. These pins can be used to read analogue voltage values from external sensors or to output analogue signals.
• Digital Pins: There are 20 digital pins labelled D0 to D19. These pins can be configured as inputs or outputs to interface with digital components such as buttons, LEDs, or other devices.
• I2C Pins: The WIO Terminal has two dedicated I2C pins, SDA and SCL, which are used for two-wire communication with I2C-compatible devices. These pins allow you to connect multiple sensors and modules that support the I2C protocol.
• UART Pins: The WIO Terminal provides two UART (Universal Asynchronous Receiver-Transmitter) pins, RX and TX, which enable serial communication with other devices. These pins are commonly used for debugging or connecting to peripherals like GPS modules or Bluetooth modules.
• SPI Pins: The WIO Terminal features a dedicated SPI (Serial Peripheral Interface) bus with pins labelled MOSI, MISO, SCK, and SS. This interface allows high-speed communication with SPI devices such as displays, SD cards, and sensors.
• PWM Pins: The board includes six PWM (Pulse-Width Modulation) pins labelled D3, D5, D6, D9, D10, and D11. These pins can generate digital signals with variable duty cycles, making them suitable for controlling motors, servos, or LED brightness.
• Power Pins: The WIO Terminal provides several power pins, including 5V, 3.3V, and GND (ground). These pins supply power to external components or can be used to power the board itself.
• Reset and Boot Pins: The board has a reset button that can be pressed to restart the microcontroller. Additionally, there is a boot button used to enter the bootloader mode for programming the board.

These pinouts offer a wide range of options for connecting and controlling external components, allowing you to interface with various sensors, actuators, and communication modules while developing your projects using the WIO Terminal.

Previous hand-made versions:

For our project, we previously created a handmade version on a protoboard, that converts the WIO terminal 40 pins into 3 PWM and 3 I2C ports, and that also has 5V power connectivity to POWER the board. But it also needs to use a 40-pin raspberry wire to connect it.

Additionally to this, I previously created a power supply board, that uses an MP1584EN step-down buck converter, to turn the 4 x 12V Inputs/outputs into 4 x 5V outputs

New Board:

The new board version integrated all of this, and more:

• 7 x I2C Grove Ports
• 5 x PWM Grove Ports
• 5 x Analogue/Digital Grove Ports
• 4 x 5V Outputs*
• 4 x 12V Inputs/outputs (one needs to be used to power the board)

I did not integrate the MP1584EN step-down buck converter, but it has the solder pins for you to buy it separately and add it to the board. Also, with this buck converter, you can also POWER the board with 12V - 36V input, but you need to regulate the output to be 5V since that is the power that the WIO terminal handles.

this board is also designed so that it can be connected directly to the WIO terminal without the need for an additional 40 Pin wire, so you could create a case that has all the connectivity and power supply on its interior, and still use the WIO terminal as the screen or control for your IoT project.

Maybe in a future version, I will add a Jack plug to power the board from a different kind of power supply, integrate the buck converter, and also add a regulator so that the WIO terminal always gets 5V, so, in that case, you can power it with higher ranges, and use the 5V outputs for more power if needed.

The Process:

I'm not going to go in deep with the design process since this is not a KiCad tutorial, but I first designed the schematics, considering the 40 outputs of the WIO terminal, added the connections for the amount of GPIOS and PWM Grove connectors I needed to have. Then I added the MP1584EN module footprint and connected that to the WIO 5V input, and to the additional power management screw pins I wanted to have.

I organized the schematics on the PCB design I wanted, reviewed that the footprints and symbols were correct, and used Autoroute external software to generate the routing of the connections. Then I added them to my schematic design files, and finally, I exported all the Gerber files, and save them as 1 single Zip File.

Seeed Fusion Production Process:

The production process with Seeed Fusion was pretty straightforward. You need to go to the Seeed Fusion webpage:

https://www.seeedstudio.com/fusion.html

Once you have imported the zip file with all your Gerber files, it automatically gets the characteristics of the board and also tells you if something you did something wrong, in case it is.

Then, you can also customize some things like the thickness of the board, the amount of different designs you have, the quantity, the material of the PCB, the colour and others (I choose a blue colour like the Seeed Studio products for mine).

After everything was set, I continued with the PCBA (assembly process) for which I just had to upload the BOM (Bill Of Materials) needed to build the PCB, and Seeed Fusion would buy them and ensemble them on the board. You can also add some test instructions for free but in my case, I didn't.

They have a BOM file template that you can fill in with the OPL (Open Part Library) available in Shenzhen, where they will get the parts from, buy them, and add them to your PCB. You can also download the library parts to add them to your KiCad or Eagle software.

Fusion Open Part Library(OPL) Service - Seeed Studio22

I made a mistake on the original BOM file, with the 40 pins header I wanted to add to my board, so they contacted me, sent me a picture and asked me how they should proceed. I told them to leave that part unsoldered and send it with the board, and I replaced it with some that I have at home.

Something I liked a lot is that they keep you informed of how the process is going so you can have live updates of what they are doing.

I will update this documentation when the board is ready, which should be in a few days because of the delay, and share with you some more pictures and use of the POWAR board.

The final result:

I must say that I am really impressed by the quality of the board produced by Seeed Fusion, it's amazing. It looks just like any other Seeed Studio product but designed by you. The process was quite simple, and the trimmings were super fast. The only delay in the process was because of my mistake in choosing the 40 pins and connectors. If you want to get your design ready to market, you can order yours at:

https://www.seeedstudio.com/fusion.html

Thank You Seeed Fusion!

I don't want to end this story without Thanking Seeed Studio and Seeed Studio Fusion for always believing in my dreams, and therefore motivating me to keep them alive.Thank you, thank you, thank you!