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Final Project

First Idea

Automated mmWave DUT OTA test setup

Requirements

As I work in the wireless development field, one challenge I face is to do the measurements in the outdoors. The setup roughly consists of an antenna panel with amplifiers and other equipment mounted on a movable stand. Depending on the goals of the measurement campaign, the antenna panel is rotated and moved manually in different directions and measurements are recorded. As expected, this is rather cumbersome task and this is the challenge I want to automate and tackle during my final project.

I want to make a mount for a cuboid which weighs roughly about 5 Kg and have dimensions of 30 by 40 cm and a depth of about 20 cm. The mount should have 6 degrees of freedom. First three degrees are related to linear movement along X,Y and Z axis and the other three degrees are related to rotation along X, Y and Z axis. A rough sketch showing the three rotational axis is shown in the sketch below.

Rotational degrees of freedom.

Finally, there will be multiple such nodes with one master and multiple slaves and controllable from one central location. With this multi node system, i will be able to automate the manual parts of the radio channel measurements.

Reflection

Given the complexity and the scale of the design, I think I will start with one rotational axis. I will be very happy if I manage to do all three rotational axis as part of the final project. Three linear axis design will be taken from other people. As I anyway not going to do any OTA measurements over the course of this year, the timelines for the finished product are more relaxed.

Research

Input Sensors

  • Distance measurement (figured out during Input week that Fablab Oulu does not have HC-SR04 (ultrasonic sensor module) and I don’t have enough time to actually make a receiver and transmitter for the distance measurement using the ultrasonic transducers.
  • Rotary encoder for exact position. Again have to make them.

Output/Control

  • Matlab via serial or Ethernet (for the master node)
  • WiFi to talk with other nodes

Second Idea

Wake up light

Requirements

A night stand lamp which can display time, has mood lighting, can change brightness of the main lamp as an alarm feature. The project has a healthy mix of mechanical and electronics design work, with mechanical being mostly enclosure and aesthetics.

Reflection

The idea is a straight ripoff from the commercial products but as the products I am trying to imitate are above 100 euros, I might still give it a try.

Input Sensors

  • Touch/button
  • Temperature
  • RGB LEDs for mood lighting
  • Bright White LED with controllable brightness
  • RTC

Output/Control

  • Connection to phone to sync time and settings. However, I don’t use an android phone and I don’t have a Macintosh computer to build an app for iPhone.

Third Idea

Tiny Keyboard and mouse that supports my laziness and also alleviates the wrist pain from constant mouse use.

Requirements

A small keypad with the ability to map multiple keystrokes/actions to individual keys

Final Project

As mentioned in the Applications and implications week, I have build a wake up light. Check the Applications and implications page for more details regarding the questions related to the assessment guide. On this page I have documented the details of the tasks related to the final project.

Presentation

Presentation slide.

Features

Right now it performs the following function

  • Mood lighting
  • Bright white light which can be turned on and off

Design

2D Design

The shade for the lamp has been designed using Inkscape and cut using laser cutter. To give the shade a diffused look, it was sandblasted on one side. For creating the shade, tabbed box maker extension was used in Inkscape with the following settings.

Creating outer lamp shade.
Creating inner case for holding the RGB LEDs.
Outer assembled lamp shade.
One side of the inner acrylic panel for holding the RGB LEDs.

3D Design

All the 3D objects were designed using Fusion 360.

The base of the lamp consists of two separate pieces, a top half which holds the two acrylic shades and the bottom part, which houses the button, OLED and other electronics. It is printed in Red ABS plastic using Stratasys Fortus 380mc 3D.

Bottom half.
Top half seen from the bottom side.

The button is made with clear resin using FormLabs Form2

Top view of the manufactured button.
Front view.
Partial assembly showing the optical sensor PCB fit in the button.

Unfortunately, the designed button was too big to install in the available cavity I made in the base of the lamp. So, in order to fit the button, I sawed off the cavity for the button and welded a new bigger cavity using acetone.

Assembly of the 3D printed button, a push button and light sensor.
The plug was designed to keep the RGB LEDs shade in place. It is also a friction joint. It was printed in PLA plastic using Sindoh 3D Vox.
Plugs to secure the RGB LEDs.
Partial assembly showing the plugs securing the RGB LEDs panel.

Electronics Design

In the final project, I have used the following PCBs

  • Power Board This board provides power to different parts of the project.
Power board.
  • LEDs Board In order for the microcontroller to be able to control the LEDs, a PMOS is there.
LEDs board, there are two copies of the same board

  • Light Sensor This board is used for the auto on/off feature.

    Bare PCB of the Light sensor

  • Atmega16U2 board

    Partially stuffed Atmega16U2 board. Check week12 documentation for details.

Testing

RBG LEDs and OLED display were tested independently. The Atmega16U2 board has been used for multiple assignments, so it is well tested. For the RGB LEDs, I used light_ws2812 library. For OLED display, I used the Adafruit_SSD1306 library.

Testing one RGB panel.
Testing the OLED display.

Assembly

Assembling the top.
Cable management in top half.
Fully assembled lamp (front view).
Fully assembled lamp (back view, showing the power connector).

License

Licensing the software is bit difficult. In my project, I have used some code which is developed by myself so of course I can use whatever license I want. On the other hand, there are code snippets and libraries which are under MIT, BSD, and GPL V3 licenses.

For the documentation (images, videos etc.,), I will use the CC BY 4.0 license.

Bill of Materials

Part Value
 Quantity
 Price ($)
Microcontroller
 ATMEGA16u2 1 3.53
Resonator 8 MHz 1 0.25
WS2812B
 28 5.1
Bluetooth Module HC-06 1 3
OLED Display SSD1306 1 2
LEDs White (160-1737-1-ND) 16 5.5
Phototransistor 940nm Top View 1206 visible 1 0.15
PMOS NDS356APCT-ND 2 0.7
Power Plug CP-012-ND 1 0.8
Power Jack CP1-023PJCT-ND 1 0.8
Capacitors Assorted ≈20 1
Resistors Assorted ≈30 0.3
Switch SW262CT-ND 1 0.74
Wires Assorted ≈1m 1
Acrylic ≈930 sq.cm. 5
ABS Plastic ≈200 cubic cm. 10
Total ≈40€

Further Development

As I am lacking a working Bluetooth module (my guess is that the module died due to an ESD event), features like wake up alarm via phone, time display etc., are missing. Furthermore, how to build an iPhone app without having an access to an apple computer is also a mystery.

Evaluation

As stated earlier also, my main objective of joining the Fab Academy program was to build my skills related to 3D design and fabrication. On that front, I have learned a lot. As my background is in embedded design, I do not consider lack of software functionality as detrimental to the success of the project. Given these facts, I do consider the project to be a success even though it lacks a lot of originally planned features.

Files

Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 International License.