Published September 28, 2020 © CC BY-NC-SA

Monty - the Maker Faire Measuring Monster

We love going to Maker Faires, but 2020 has decided otherwise. So instead, we are building a suitable substitute called Monty, who will capt

IntermediateFull instructions provided15 hours253

Monty - the Maker Faire Measuring Monster

Things used in this project

Hardware components

Raspberry Pi 4 Model B

PIR Motion Sensor (generic)

Evaluation Board, ADS1015 12-Bit ADC

Sounds Sensor

Adafruit NeoPixel Ring: WS2812 5050 RGB LED

Bird Cage

Fake Fur

Red Paint

Plastic ornament balls

Round furniture pads

White spray paint

Software apps and online services

ThingSpeak API

Hand tools and fabrication machines

Soldering iron (generic)

Glue

Multitool, Screwdriver

Needle and thread

Cleaning supplies

Story

Project Video

The Idea

In short, our project will travel to Maker Faire, measure the atmosphere using a number of sensors, save the data and return home, all whilst looking amazing.

With this idea, there are some things to keep in mind:

International shipping: it has to fit inside a box, arrive safely and not cause any kind of panic, so you’ll be limited in weight, size and contents. To be on the safe side, it’s best to buy a box at your local postoffice and work from there.
Plug & play: to limit the hassle at the event itself, the project only has to be plugged in for it to work.
Privacy: we want to capture the atmosphere at the event, but not intrude on the privacy of the people attending it.
Connectivity: reliable wireless internet is never a guarantee at events, so our device will have to function both online and offline.

That sounds like a fun challenge, let’s get to work!

Setting Up the Sensors and Hardware

First things first, we’ll start by capturing the mood using a Raspberry Pi, a sound level sensor and a motion sensor.

We opted for these two sensors as you can get a bit of a feel of the event, whilst also respecting the privacy of the visitors. You can detect when there’s a lot of movement going on or none at all, without registering who walks by at what time. You can notice if it’s currently very quiet or really loud, without recording any audio.

Raspberry Pi If you’re new to Raspberry Pis, there’s a great getting started guide here on the Raspberry Pi website.

Motion Sensor To learn more about motion sensors and how to connect them to the Raspberry Pi, you can follow these steps in the Parent Detector Project by the Raspberry Pi Foundation.

Sound sensor & ADCAs the output of our sound sensor is analog, but the Raspberry Pi can only receive digital input, we’ll need to convert our analog values to digital ones using an Analog to Digital Converter (ADC).

Adafruit provides this great tutorial on setting up and getting started with their ADC breakout board right here.

NeoPixel RingWhat’s a monster without some pizzazz? That’s where a NeoPixel Ring comes in handy. To light up your monster, you can follow the steps outlined in the Adafruit NeoPixel Überguide.

Full Code and Schematics Don’t worry if you don’t feel like following all these different tutorials to get your monster up and running, as we’ve added the full code and final schematics of this project to this step!

The code does the following: - Import all the libraries and configure the hardware

- Every second:

Change the color of the NeoPixel Ring
Measure the noise level
Detect motion
Get the current time in Epoch
Save the collected data locally to a JSON file (see next step)

- Every minute:

Try to send the latest measurement to the Thingspeak IoT Platform (see next step)

To run your code on startup there's a fantastic guide right here.

One of the key elements of our project is that it shares its findings with the world, which is what we’ll jump into in this step.

Online with ThingSpeakWhen our creature has an internet connection, it would be great if it sends the latest measurements to an IoT platform that’s accessible to everyone, like ThingSpeak.

To learn more about creating a ThingSpeak channel and collecting data with it, check out their getting started tutorial.

The code to send your data to ThingSpeak has already been added to the previous step, all you need to do is add your own API key.

You can check out the Montys channel here!

Wifi CredentialsBecause Monty will be attending Maker Faire on his own, we’ll have to configure his internet access before he leaves.

If you happen to have the network connection details of the event, you can add them to your Raspberry Pi beforehand by following this guide written by the Raspberry Pi Foundation.

Offline with JSON

No need to panic if you don’t know the wifi credentials or if the internet connection is spotty, we’ll also save the data locally on the Raspberry Pi in a JSON file. This way, you’ll have a record of the atmosphere of the event that you can access the moment your measuring monster returns home.

If you’ve never worked with JSON before, W3Schools has a pretty good introduction here.

To analyse the JSON data, you can import it into your free data processing tools like the Google Data Studio or you can go nuts in R.

Creating a Monster

Birdcage

As luck would have it, we found an old bird cage that nicely fits inside the biggest shipping box our local post office provides.

To prep it for monsterification, we cleaned it, removed the bird sitting sticks, figured out how to remove the cage bars and painted the insides red.

Hardware

After the paint dried, we attached the hardware to the bottom of the cage using a set of tiny screws. Make sure to leave a little bit of wiggle room, so there’s not too much tension on your electronics.

Monster

To create the monster, add plenty of fake fur! We glued a patch to the top of Montys head and hand stitched another piece to the bars of the cage.

For his three eyes, we spray painted the insides of two decorative christmas ornament balls white. We attached three halves to the fur on Montys head using some very strong glue. The finishing touches are three round furniture pads that function as pupils.

Measuring Maker Faire

To round off our project, we designed a poster with a bit of an explanation about Monty The Measuring Monster to give the visitors of Maker Faire a bit of context.

Finally, we packaged Monty securely and shipped him off to Eindhoven Maker Faire. We really hope he survives the journey and has a wonderful time at the event!

If Monty has an internet connection, you can check out his measurements here on ThingSpeak. We’ll also keep you posted on his adventures via our Instagram and Twitter!

Code

MontyClean.py

# Generic Imports
import time
import requests
import board
import busio
import threading
import json
from random import randrange

# Setup motion sensor
from gpiozero import MotionSensor
pir = MotionSensor(4)

# Initialize I2C bus and sensor.
i2c = busio.I2C(board.SCL, board.SDA)

# Analog Digital Converter setup
import adafruit_ads1x15.ads1015 as ADS
from adafruit_ads1x15.analog_in import AnalogIn
ads = ADS.ADS1015(i2c)
chan = AnalogIn(ads, ADS.P0)

#NeoPixel Setup
import neopixel
pixels = neopixel.NeoPixel(board.D18,30)
red = (252, 3, 3)
orange = (252, 177, 3)
yellow = (252, 248, 3)
green = (3, 252, 53)
blue = (0, 213, 255)
indigo = (115, 3, 252)
violet = (242, 0, 255)
rainbow = [red, orange, yellow, green, blue, indigo, violet]
nocolour = (0,0,0)

def readSensors():
    
    readings = {}

    noise = chan.value
    readings['noise'] = noise

    movement = pir.value
    readings['movement'] = movement

    epoch = int(time.time())
    readings['epoch'] = epoch

    return readings

def saveToJSON(readings):
    
    try:
        filePath ='/home/pi/mm/data.json'
        input_file_data = open(filePath)
        readingsFile = json.load(input_file_data)
        
    except:
        readingsFile = []

    readingsFile.append(readings)
    
    with open(filePath, 'w') as outfile:
            json.dump(readingsFile, outfile) 

            
def sendData(readings):
    
    url = 'Your super Secret URL, '.format(eventId,readings['epoch'],readings['noise'],readings['movement'])
    response = requests.request("GET", url)

# Tracking variables
secondsPassed = 0
eventId = 0

while True:

    secondsPassed += 1
    time.sleep(0.999)

    colour = randrange(len(rainbow))
    pixels.fill(rainbow[colour])

    readings = readSensors()
    saveToJSON(readings)

    if secondsPassed == 60:

        secondsPassed = 0
        sendDataThread = threading.Thread(target=sendData(readings))
        sendDataThread.start()

Monty - the Maker Faire Measuring Monster

Things used in this project

Hardware components

Software apps and online services

Hand tools and fabrication machines

Story

Project Video

The Idea

Setting Up the Sensors and Hardware

Creating a Monster

Measuring Maker Faire

Schematics

Poster

Wiring Diagram

Code

MontyClean.py

Credits

Comments

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Monty - the Maker Faire Measuring Monster

Monty - the Maker Faire Measuring Monster

Things used in this project

Hardware components

Software apps and online services

Hand tools and fabrication machines

Story

Project Video

The Idea

Setting Up the Sensors and Hardware

Data Collection and Sharing

Creating a Monster

Measuring Maker Faire

Schematics

Poster

Wiring Diagram

Code

MontyClean.py

Credits

Comments

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