W18.  Project Development

My project is:

acoustic panel by ak 0.0

An acoustic Panel that could transform at a certain level of decibels from a flat piece in to a tridimensional object. This panel will improve the acoustic of a room and will use the minimum space from ceiling.

1. THE IDEA

This is the process I follow for the development of my project. In the beginning my goal was to design and build an acoustic panel that could be used as a wall or division or as a ceiling panel.

As I am new in the use and production of electronic devices I decided to explore the use of sensors and a mechanical device to move a a single module of that panel. In the fase I (Fab Academy) I will design and build an structure, the mechanism for movement and a microcontroller board.

The elements that I will use are:

• sound sensor (W 503 DC009)
• servo motor (Tower Pro MG996R 180º Digi Hi Torque)
• my version of Daniele Ingrassia fabduino kit (Shasatshakit with a microprocessor  328AU P)
• connection cables
• structure: 3mms wood sheet for the box, in this fase paper for the panel, sewing thread.

The process and machines I will use:

• laser cutting (structure)
• milling (pcb)
• 3d printing (mechanical)

2. THE PROTOTYPE – acoustic panel by ak 0.0

I designed the  module using an origami form so the piece could be folded and unfolded easily by a simple structure with a single point of contact.  The material to use for the panel in this fase 0.0 is paper and for the structure I used wood. The structure will move the folded piece at a moment when the sorrounding sound gets noisy (in next fase I will improve the combination of the code in order to get a better control of the sound).

The panel:

I experiment some of the folding techniques by Paul Jackson. I selected the ones on the next images, I think that this models could be easy to fold and unfold by one point force.

I used Rhinoceros to draw the panel pieces  of the single module, in the future I want to experiment not only with cotton paper but also with fabric and wood. I think those materials will improve the acoustic absorption. In Rhinoceros I have an example to engrave (blue line) and pieces to laser cut (red line).

The structure:

I decided to use wood for the structure, it will be not that expensive and also it will be resistant and easy to build. First I continue designing it by defining the size of the space I will need to contain the electronics and the motor as well as the panel. The little box (container or case) will have 6 cms of height and width; and 32 cms of long. The wood I am using is banak with 6mms of thickness. The line I am using is color red because I will use the laser cutting.

I am using press and fit to assembly the pieces of the box. file.dxf

I assembly the pieces of the box, the paper panel and the structure to check the dimensions and the mechanism.

It seems to be working perfectly with the dimensions so I decided to design a hinge to move the panel in an axis. I tried an arduino and also a fabkit to move the servo motor with the panel and the box.

After the first test I have to redesign the border sides of the box and ad a hinge.

I used rhino again but for the hinge I needed to work in 3D for 3D printing. I used Rhinoceros to draw and design; and the Uprint to print the object. file.stl

Electronics and Mechanism

I needed a microcontroller to move a servo and also for the mic or sound sensor. I decided  to use Daniele Ingrassia’s Fab Kit call satshakit, we tried it and work perfect but not exactly for what I need. As I am using a servo and a sensor I will need to add power (vcc and ground jacks) and modify the routes to have the exact number of pins I need.

 

board, schematic, png, edge, routes and perforations.

 

 

BOM:

list of components I used in my microcontroller acoustic panel by ak and the rest of the project:

materials		units	cost	supplier
3 mms wood panel (plywood)	(a piece of 40cmX122cms)	1	$3.00	local store
servo motor	(Tower Pro MG996R 180º Digi Hi Torque)	1	$19.95	adafruit
mic/sound sensor	3-6v module sound sensor	1	$3.00	5hertz local store
jumper female to female (x10)	932-MIKROE-511	2	$3.90	mouser
ftdi serial usb	768-1028-ND	1	$17.95	adafruit
microcontroller
Atmega328P-AU	556-ATMEGA328P-AU	1	$3.93	Mouser
crystal 16 Mhz/ 18 pf	815-ABLS3-16MD4YT	1	$16.25	Mouser
switch	311-499FRCT-ND	1	$0.59	Digikey
led green	859-LTST-C150GKT	1	$0.18	Mouser
led red	941-CLV1LFKBC7673673	1	$0.21	Mouser
10K resistor	603-RC1206FR-0710KL	1	$0.01	Mouser
499 resistor	603-RC1206FR-07499RL	2	$0.03	Mouser
22pf capacitor	77-VJ0805A220JXGAT5Z	2	$0.46	Mouser
10uf capacitor	963-GMK316F106ZL-T	1	$0.96	Mouser
1uf capacitor	810-C3216X7R1H105K	1	$0.22	Mouser
0.1uf capacitor	80-C1206C104KAR	2	$0.21	Mouser
1×6 jumper	ED65508-ND	1	$0.18	Digikey
1×9 jumper	ED65508-ND	1	$0.27	Digikey
1×2 jumper	ED65508-ND	3	$0.06	Digikey
1×1 jumper	ED65508-ND	1	$0.03	Digikey
			$71.38

Programming

To program my microcontroller I used Arduino Uno as ISP to boatloader the Atmega. I follow instructions adding  a capacitor of 10uf to my arduino board and follow the process to burn boatloader.

After the boatloader was completed I test the microcontroller with the sketch “blink”.

After finishing the process I connected the servo motor with the microcontroller and also the sound sensor to check the movement expected.

The code that I used as a test is in the sketch examples of the Arduino IDE, I selected servo knob and modify angle and delay fron 15 to 100.

#include <Servo.h>
 Servo servo;
 int pot = 3; // pin A3 para potenciometro pin interno; pin digital 6 para cable amarillo del servo, el pin izq del potenciometro es voltaje, de ahí al arduino uno.

void setup() {
  Serial.begin (9600);
 servo.attach (6); 
 }

void loop() {
 int valorpot = analogRead (pot);

int val = map (valorpot, 0, 1023, 0, 180);
 Serial.println (val);
 servo.write (val);
 delay (100);
 }

and for sound I used as a test a code  suggested by adafruit from the microphone amplifier:

const int sampleWindow = 50; // Sample window width in mS (50 mS = 20Hz)
 unsigned int sample;
 void setup()
 {
 Serial.begin(9600);
 }
 void loop()
 {
 unsigned long startMillis= millis(); // Start of sample window
 unsigned int peakToPeak = 0; // peak-to-peak level
 unsigned int signalMax = 0;
 unsigned int signalMin = 1024;
 // collect data for 50 mS
 while (millis() - startMillis < sampleWindow)
 {
 sample = analogRead(0);
 if (sample < 1024) // toss out spurious readings
 {
 if (sample > signalMax)
 {
 signalMax = sample; // save just the max levels
 }
 else if (sample < signalMin)
 {
 signalMin = sample; // save just the min levels
 }
 }
 }
 peakToPeak = signalMax - signalMin; // max - min = peak-peak amplitude
 double volts = (peakToPeak * 3.3) / 1024; // convert to volts
 Serial.println(volts);
 }

I got a great result, the microcontroller moves the servo and the panel; and it captures sound levels; also the structure is strong enough to mantain the panel in its place.

3. WHAT’S NEXT:

I will continue working with the code for the sound sensor, I want to have the movement by the sound level. At this moment both codes work perfect but separated.

I also want to continue working with other materials, as I mention before I experiment with wood + fabric for the panel. I have the piece but I will need to change the servo motor to a bipolar stepper motor or a bigger servo, but it will make my project real expensive.

Here is the panel which I will continue working. It looks great but it is to heavy for the structure and the servo motor.

4. CONCLUSION:

I realize after 19+ weeks that this journey was amazying, frustrating sometimes but the balance is that I have learned a lot. I was a beginner in almost every subject of this course and now I feel that I can make “almost” anything. I have enjoy every assignment and the most important part of it was to work at a side of a great team: Fab Lab Monterrey / CRGS and the great people that students from all over the world are.

I am sure that I will continue studying and experimenting all that I have started in the Fab Academy 2015.