wearable

PixelPad Indian: Electronic Development Badge

PixelPad is an electronic development badge based on an ATmega32U4 microcontroller and comes with a lot of built-in features. The PCB art is inspired by Indian culture, arts, and drawings. Using PixelPad, you can either use it as a wearable development board like the Adafruit Playground Express or LilyPad, or you can use it as an electronic badge!

The features of PixelPad can be seen below!

I went through many Indian cultural and spiritual arts and paintings to design the PCB art and board outline. After a lot of research and leanings, I designed a PCB art using Adobe Illustrator.

Let me explain the process and the experiences I went through to build my own electronic badge.

The Idea

When I decided to build an electronic badge, I was gone through many ideas. That lead me into confusion regarding which one I need to design, Literally I don’t stick with an idea. instead of I am rapidly changing the ideas. So what I did is, I listed out the features that I wanted in the badge that am designing. So here are the criteria that I listed out in the idea sparking process.

  • Minimalist design
  • Compact in size
  • The design should be Wearable friendly
  • Have enough I/O pinouts
  • Must be battery powered
  • Have good LEDs that can be programmable to something useful
  • Represent a culture or art

After going through the rough list, I started to search which Microcontroller, LEDs that I need to use for the Pixelpad. Finding a good theme for the art is too complicated for me, you know it right?

I don’t have that skill!

The Microcontroller (ATmega32U4)

I decided to use the Atmega32U4 microcontroller for the badge design. It comes with USB support and supports data transfer rates up to 12Mbit/s and 1.5Mbit/s. It can also be used as an HID device. So, I stuck with ATmega32U4 as the MCU. You can definitely check out the datasheet I attached to this project.

The WS21812B 5050 NeoPixel LEDs

I used 12 NeoPixel LEDs because every led can addressable and a single Data pin needed to control the RGB colors. So, I decided to stick with NeoPixels.

Schematics Designing

I used Autodesk Eagle CAD to design all my PCBs. I started to design the circuit Schematics in Eagle. The main components that I used in the schematics are explained below.

  • MIC5219B for a 3.3V 500ma power supply to power the microcontroller
  • MCP73831 for Li-Po / Li-Ion battery management
  • DS1307Z for an I2C RTC
  • WS2812 5050 RGB LEDs
  • 8Mhz Resonator to clock the ATmega32U4 externally
  • 2×3 SMD pin header for ISP connection
  • SMD reset push button

Board Designing

After the schematics designing, I started to design the printed circuit board (PCB). First, I placed all the components in an order that I wanted. Then started to route the air wires manually. I used a minimum trace width of 8mils for the traces. The board design is for a two-layer PCB. the overall dimension is 66 x 66 mm. You can find the design files and Gerber files attached at the end of this project.

Import PCB Art to the Board

I designed the PCB art in Adobe Illustrator. You can use any vector designing software to do this part. You can either use an illustrator or stick with an opensource one like the Inkscape. I tried a lot of design and in the end, I made it to the expected design. After designing the art you can save it as an 8-bit BMP format.

Then in Eagle, you need to import the art to any silkscreen layer. I used the name layer. I don’t want the component layer so I deleted the names and used the layer to place the design. to import the design follow the below steps:

  • On the top, you can find the ULP icon, by clicking the icon you get the popup window to select the ULP. The search for import-BMP then opens the import-Bmp ULP.

Then select the BMP file you needed and the layer you wanted to place and scale measurements etc… and click OK. After that, you need to place the design in the PCB design where you wanted.

NB: Design should be in black and white color

I used Autodesk Fusion 360 to view the 3D model of the PCB, I also used Fusion 360 to design the board outline for the dimension layer. You can definitely use the advantage of Fusion 360 and Eagle integration.

Exporting the Gerber File for Manufacturing

For manufacturing the PCB from any manufacturers around the globe, you need the Gerber file sent to them. Generating the Gerber file in Eagle is super easy. You can follow the steps below.

On the right side of Eagle, you can find Manufacturing tab. Click on the manufacturing tab you can see the rendered image of the PCB for manufacturing. In the same window click on the CAM button.

Save each layer into a folder and compress the folder into a zip format.

PCB Manufacturing

There are a lot of PCB manufacturing services in China for cheap as $5 for 10 PCBs. I personally recommend PCBWAY They deliver good quality PCBs and the customer care support is awesome.

Components Gathering

The PCBs take two weeks to arrive according to the delivery method. Meanwhile, I started to collect the required components for the project. I already have some of the components, so I bought the remaining components from different sources. But I have given all the components link to the store.

Soldering the Components

After arriving both the PCBs and the components. I started soldering the components. using a weller we51 soldering station with a micro tip for soldering. the 0805 SMD package is a little hard for soldering for newcomers but you guys will be used to it after a few components soldered. I also used a hot air rework station but it is not necessary. Be careful while soldering the microcontroller and other ICs do not overheat the ICs.

I also used a PCB cleaning solution to clean the PCB from the excess solder flux.

Programming the Pixelpad Indian Board

I Soldered all the components on the PCB. To program the board using Arduino IDE first we need to burn an appropriate Atmega32u4 bootloader to the board. I used the Sparkfun pro micro board’s bootloader for my board. To Burn the bootloader you needed is ISP programmer or you can use an Arduino board as an ISP programmer. I build a USBTiny ISP programmer myself, visit my USBTinyISP programmer page.

When connecting the Pixelpad Indian, the power LED will light up.

I chose the Sparkfun Pro Micro board from the board manager and select the USBTiny ISP as the programmer from the programmer window. Then click the burn bootloader. It will take a little time to burn. After burning the bootloader, It is ready to program via the micro USB cable.

I made a basic sketch to show an analog clock time using the NeoPixel LEDs and RTC. The red LEDs show the hours and the blue LED shows minutes.

Eg: Lets say 3 : 30 || The 3rd LED will lights RED and 6th LEDs lights BLUE.

You can download all the files and resources to do this board from the end of this project.

Demo Video

Here is the working video of the above-mentioned sketch.

Xpedit – Atmosphere Monitoring Device for Hiking and Trekking

:: This project is paid sponsored by Instructables.com & pcbway.com

When you are planning to do an adventure journey or trekking to the wild, it is essential to have a device in your backpack that helps you to understand the environment.

For my upcoming adventure trip, I planned to build a handheld device that helps me to monitors temperature, humidity, air pressure, and altitude as well as an alarm can be set for any of the parameters that go beyond a user-defined threshold value. The device is powered with 1000maH lipo battery, with a backup of 72 Hours continuous running!

I made this device smaller in size, smarter to use, looks cool in your hands and durable outdoor. I keep the budget within $18!

Step1: Get the Parts and Tools!

Component and Parts :

Tools:

  • Soldering Iron
  • Multimeter
  • Allen key 3mm Screw Drivers
  • Tweezers
  • Files

Supplies:

  • Spray Paint (any color for your choice)
  • Spray paint clear coat
  • Sandpapers, Gloves, Mask, and Googles

Softwares:

Machines:

  • 3D Printer
  • Vinyl Cutter Machine (Not necessary, Just for cutting logo)

Step 2: Designing PCB Using Autodesk Eagle

I use Autodesk Eagle to design all my projects PCBs. It is free and easy to kickstart learning PCB designing.

I used fusion 360 to design the outline of the PCB and the enclosure for 3D printing. It is simpler by syncing the eagle project into the fusion 360 projects. I used the 3D model of the PCB (designed in Eagle) in fusion360 and I modified the outline of the PCB in Fusion360 and export it back to Eagle.

For Designing the Xpedit I used Atmega328p-AU as the microcontroller along with 20mhz resonator. Using BME280 is capable of sensing temperature, humidity, air pressure, and altitude. I Used 128 x 64 OLED to display the information. Xpedit is power by a 3.7V lipo battery, TP4056 is used to charge the battery accordingly. A buzzer and button-sized Vibrator motor are used for notification. A rotary encoder is used for user inputs and for changing into various modes.

You can download the Eagle Project files and Gerber Files from the GitHub

I ordered 10 PCBs of xpedit from Pcbway. I always choose pcbway because of their high-quality PCBs for cheaper price and a great one to one customer support!

If you want to directly manufacture the PCBs. check out PCBWAY

Step 3: Designing Enclosure Using Fusion360

I use Fusion360 for 3D modeling. Like I said we can sync the projects between Autodesk Eagle and Autodesk Fusion 360. It is easy to design an enclosure for the PCB with the help of the sync feature. I designed a minimalistic Enclosure for the Xpedit.

I also used 3mm brass threaded inserts for holding the enclosure parts as much stronger.

Step 4: 3D Printing the Enclosure Parts

Depending on what you need, you could modify the enclosure parts to suit your needs. You could use bigger capacity batteries or more sensors etc…

If you want to stick with the default design, then you can download the files from Github.

I used Ultimaker 2+ for 3D printing the parts. You can use any 3D printer that you have access to!

Step 5: Sanding the 3D Printed Parts

It took me about 8 hours of printing, But it really depends on your 3Dprinter and the slice settings!

After 3D printing the parts, I used Files and sandpaper for smoothening rough edges. It is better to use small files as I used in the above image

  Step 6: Install Threaded Inserts

I am using M3/6mm Threaded Inserts for screwing the lid to the bottom enclosure. If you’re using the same version of mine, You can install them now. These inserts will hold the PCB inside the enclosure and hold the lid strong!

Step 7: Spray Painting and Clear Coating the Enclosure

For a better and neat look, I used spray paint. You could use any color that you like. I used black as my choice. I did two coats of black spray paint. It is better to use a spray clear coat to protect the painting from peeling off!. Before you do spray painting, cover the threaded inserts using small pieces of masking tape. After painting the black color, I cut out an “XPEDIT” vinyl sticker using a vinyl cutter machine and stick it on the lid. Then i spray painted the clear coat to protect the paint and sticker.

Step 8: Soldering Components

Start soldering with the smallest components first. Probably the resistors and capacitors and then move your way to the larger ones. If you are soldering SMD components in your first time, it is a little bit hard to solder. Don’t worry, you will become used to after soldering a few components!

Step 9: Load Firmware in to the Xpedit

Time to upload your code and let the microcontroller do the work for you!

Do not use the Arduino NANO’s or UNO’s board bootloader. We are using 20Mhz Clock. Use the custom Atmega328p board manager from the below Link.

To upload the bootloader use an ISP programmer or use your Arduino as ISP. If you want to build Your USBtiny ISP programmer, check out my instructable to build one yourself from the link below. This is the same ISP that I am using to upload the firmware!

Download and upload the firmware from Github!

Link to the Custom Atmega328p Board manager for Arduino

Link to the Build your own USBtiny ISP programmer

Step 10: Place the Board in Enclosure!

Place the Board in Enclosure!

After uploading the firmware and everything goes good. You can place the board Inside. Before placing the board, First, place the Vibrator motor and apply a little hot glue or place a foam seal on the top of the motor and solder the wires to the pads on the board. Place the Slide Switch into the Lid and apply some hot glue to hold up the switch. Solder the switch Wire to the PWR Header pads on the PCB. At last, insert the battery into the battery slot and guide the wire through the channel. Solder the Redwire to the +(Plus) Header and Black Wire to the -(Minus).

Remove the header pins from the OLED display and place it in the Display Slot on the LID. Make use of a Duct tape or any tape with a strong bond for placing the display in the slot. Use Hot glue if necessary. Use a four-wire ribbon cable to connect the display on to the PCB.

Place the PCB in the enclossure and put the lid on. Use the four M3/15mm Screws to hold the enclosure. Stick the small compass into the slot on the lid using a two-part adhesive!

I used hot glue in a few places on the PCB, like the USB port, Display, and Switch for a strong bond.

Put on the Knob we printed earlier on to the rotary encoder after everything put together!

Step 11: Deploy

Now that’s it!

Don’t forget to take the Xpedit on your next Adventure trip!

All the files will be available in Github
If you want to put some new features on to xpedit Follow the project on Github!

This project is free and open-source. If you like what I do and want to support my projects consider following me on:

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