0. Assignments for wk13


The assignments for wk13 were as below;

  1. Add an output device to a microcontroller board you've designed and programme it to do something.

1. Making Speaker Board


For the assignment of this week, I decided to make the speaker board which I can add it to Fabkit, which I made Input Device week since I have to implement the speaker module to my final project.


Designing the board

First, we made a lough sketch of the schematic with a lot of help by Emma. The challenge was that I had to add reguralor to decrease the voltage because the appropriate voltage for Fabkit was mainly 5V, however, that for the speaker module was 9V.

Therefore, I added a 5V and 1A regulator to down the voltage from 9V to 5V and two capacitors to stabilize the current as the sketch below with reffering the datasheet of Regulator: LM2940C.


Designing the board on Eagle

After fixing the hand-written schematic, I wrote the schematic on EAGLE. However, I made several mistakes in this designing step.


Mistake1: Wrong Connection

Fisrt, I wrote the schematic following the concept sketch above, and milled the board, solderred parts, however, it did not work in the end.

After several debugging I found that I made mistake when I wrote the schematic; I forgot to PIN NHOS as below. This error created one trash in this world...


Wrong schematic of speaker board


Mistake2: Wrong MOSFET

Next mistake was to use the wrong MOSFET, which was a voltage controlled field effect transistor .

There were two MOSFET in the inventory in Fablab Amsterdam.

  • NDS356AP: P-channel
  • NDS355AN: N-Channel

  • Though I should have used MOSFET of N-Channel in this project, I wrongly used P-Channel parts on the board as below. So I have to change the schematic and the my inventory.

    Wrong board with MOSFET of wrong direction


    Production

    After several trial as above, I finished designing the right schematic and the board as below.

    20160609_speaker.sch

    20160609_speaker.brd


    Finally, I exported PNG file for tracing and cutting by modela as below and finished the designing part.

    20160609_speaker_trace_v4.png

    20160609_speaker_cut_v4.png


    Soldering the parts to the board

    After that, The soldering part was also finished straigtforward. Here is the speaker board which I made.


    Writing the code

    Next, I wrote the test code on Arduino for checking if the speaker board were working correctlly or NOT as below.

    20160610_speaker_v2.ino

    #define BEAT 300   // define the length of the sound
    #define PINNO 2   // Pin number
    
    void setup() {
    }
    void loop() {
         tone(PINNO,262,BEAT) ;  // C
         delay(BEAT) ;
         tone(PINNO,294,BEAT) ;  // D
         delay(BEAT) ;
         tone(PINNO,330,BEAT) ;  // E
         delay(BEAT) ;
         tone(PINNO,349,BEAT) ;  // F
         delay(BEAT) ;
         tone(PINNO,392,BEAT) ;  // G
         delay(BEAT) ;
         tone(PINNO,440,BEAT) ;  // A
         delay(BEAT) ;
         tone(PINNO,494,BEAT) ;  // B
         delay(BEAT) ;
         tone(PINNO,523,BEAT) ;  // C
         delay(3000) ;           // Repeat after 3 seconnds
    }
    

    Production

    Then finally, I was able to get sounds from the speaker, and successfuly made the baord.

    Speaker board with external battery

    VIDEO(1): Speaker board with FTDI


    Also, it worked not with FTDI cable but with external battery, and I could got good progress on my final project.

    VIDEO(2): Speaker board with external battery


    Outline of this page


    1. Making Speaker Board



    Download output of Wk13


    Here are my output files for wk13:

    (Speaker board)

    (Programming)



    Lecture Material for Wk13


    Lecture Note

    Tools



    Videos of Wk13


    Here you can find this weeks's lectures on VIMEO:

    (2016.04.27)

    (2016.05.04)



    Checklist for Wk13


    Assignments:
    • Add an output device to a microcontroller board you've designed and programme it to do something.
    Learning outcomes:
    • Demonstrate workflows used in circuit board design and fabrication
    • Implement and interpret programming protocols
    Have you:
    • Described your design and fabrication process using words/images/screenshots.
    • Explained the programming process/es you used and how the microcontroller datasheet helped you.
    • Outlined problems and how you fixed them
    • Included original design files and code