Parking Buddy - Arduino Neopixel IOT Parking Assist

Have you ever wanted a high tech parking assistant? Its time to put away your hanging tennis ball and get into the 21st century with an electronic parking buddy. This project uses an ultrasonic sensor and a nexopixel ring to light up and complete the ring as your get closer to the sensor.. When you are at your maximum distance (closeness) the ring will be full, (fades from green to yellow.. If you get to close it will flash red to warn you your in panic mode!

So what will you need to create your own tiny tiny parking buddy!

1. Ultra Sonic Distance Sensor - HC-SR04 Less than $1 online
2. NeoPixel Ring - 24 x 5050 RGB LED with Integrated Drivers - ~ $17
3. Arduino nano or mini pro - $2-5
4. An enclosure - Free if you have a 3d printer, or find a DIY container
5. 5v Power-supply
6. 470 ish ohm resistor / 1000uf capactior
7. 3.3v regulator (if you go with the arduino micro pro)

I started the project using an arduino nano but later swapped it to a micro pro as i wanted it to run at 3.3v to simplify adding wifi to the project (optional future step). My next Addition will be having the sensor either host a webpage saying if a car is present or not.... or having the sensor update a larger system which i have not yet built :)

Copy the code below into your arduino sketch and upload to your board. This code was origionaly found on the mysensor site and modified to suite my project.

/**
 * This code has been modified from the original MySensor code to fit this project.
 * 
 * The MySensors Arduino library handles the wireless radio link and protocol
 * between your home built sensors/actuators and HA controller of choice.
 * The sensors forms a self healing radio network with optional repeaters. Each
 * repeater and gateway builds a routing tables in EEPROM which keeps track of the
 * network topology allowing messages to be routed to nodes.
 *
 * Created by Henrik Ekblad 
 * Copyright (C) 2013-2015 Sensnology AB
 * Full contributor list: https://github.com/mysensors/Arduino/graphs/contributors
 *
 * Documentation: http://www.mysensors.org
 * Support Forum: http://forum.mysensors.org
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * version 2 as published by the Free Software Foundation.
 *
 *******************************
 *
 * REVISION HISTORY
 * Version 1.0 - Created by Henrik Ekblad
 * 
 * DESCRIPTION
 * Parking sensor using a neopixel led ring and distance sensor (HC-SR04).
 * Configure the digital pins used for distance sensor and neopixels below.
 * NOTE! Remeber to feed leds and distance sensor serparatly from your Arduino. 
 * It will probably not survive feeding more than a couple of LEDs. You 
 * can also adjust intesity below to reduce the power requirements.
 * 
 * Sends parking status to the controller as a DOOR sensor if SEND_STATUS_TO_CONTROLLER 
 * is defined below. You can also use this _standalone_ without any radio by 
 * removing the SEND_STATUS_TO_CONTROLLER define.
 */

//#define SEND_STATUS_TO_CONTROLLER  // Put a comment on this line for standalone mode

#include 
#include 

#ifdef SEND_STATUS_TO_CONTROLLER
// Enable debug prints to serial monitor
#define MY_DEBUG 

// Enable and select radio type attached
//#define MY_RADIO_NRF24
//#define MY_RADIO_RFM69

#include 
#include 
#endif

#define NEO_PIN      6 // NeoPixels input pin

#define TRIGGER_PIN  3  // Arduino pin tied to trigger pin on the ultrasonic sensor.
#define ECHO_PIN     2  // Arduino pin tied to echo pin on the ultrasonic sensor.

#define NUMPIXELS      24 // Number of nexpixels in ring/strip
#define MAX_INTESITY   20  // Intesity of leds (in percentage). Remeber more intesity requires more power.

// The maximum rated measuring range for the HC-SR04 is about 400-500cm.
#define MAX_DISTANCE 100 // Max distance we want to start indicating green (in cm)
#define PANIC_DISTANCE 50 // Mix distance we red warning indication should be active (in cm)
#define PARKED_DISTANCE 60 // Distance when "parked signal" should be sent to controller (in cm)

#define PARK_OFF_TIMEOUT 20000 // Number of milliseconds until turning off light when parked.

// Note that for older NeoPixel strips you might need to change the third parameter--see the strandtest
// example for more information on possible values.

Adafruit_NeoPixel pixels = Adafruit_NeoPixel(NUMPIXELS, NEO_PIN, NEO_GRB + NEO_KHZ800);

NewPing sonar(TRIGGER_PIN, ECHO_PIN, MAX_DISTANCE); // NewPing setup of pins and maximum distance.


//#ifdef SEND_STATUS_TO_CONTROLLER
//#define CHILD_ID 1
//MyMessage msg(CHILD_ID,V_TRIPPED);
//#endif
unsigned long sendInterval = 5000;  // Send park status at maximum every 5 second.
unsigned long lastSend;

int oldParkedStatus=-1;

unsigned long blinkInterval = 100; // blink interval (milliseconds)
unsigned long lastBlinkPeriod;
bool blinkColor = true;

// To make a fading motion on the led ring/tape we only move one pixel/distDebounce time
unsigned long distDebounce = 30; 
unsigned long lastDebouncePeriod;
int numLightPixels=0;
int skipZero=0;

void setup() {
  Serial.begin(9600);
  Serial.println("Starting distance sensor");
  pixels.begin(); // This initializes the NeoPixel library.
  Serial.println("Neopixels initialized");
}

//#ifdef SEND_STATUS_TO_CONTROLLER
//void presentation()  {
//  sendSketchInfo("Parking Sensor", "1.0");
//  present(CHILD_ID, S_DOOR, "Parking Status");
//}
//#endif

void loop() {
  unsigned long now = millis();
  unsigned int fullDist = (sonar.ping_median() / US_ROUNDTRIP_CM);
//  Serial.println(fullDist);
  int displayDist = min(fullDist, MAX_DISTANCE);
  if (displayDist == 0 && skipZero<10) {
    // Try to filter zero readings
    skipZero++;
    return;
  }
  // Check if it is time to alter the leds
  if (now-lastDebouncePeriod > distDebounce) {
    lastDebouncePeriod = now;

    // Update parked status
    int parked = displayDist != 0 && displayDist sendInterval) {
      if (parked)
        Serial.println("Car Parked");
      else
        Serial.println("Car Gone");
//#ifdef SEND_STATUS_TO_CONTROLLER
//      send(msg.set(parked)); 
//#endif
      oldParkedStatus = parked;
      lastSend = now;
    }

    if (parked && now-lastSend > PARK_OFF_TIMEOUT) {
      // We've been parked for a while now. Turn off all pixels
      for(int i=0;inumLightPixels) {
          // Fast raise
          numLightPixels += max((newLightPixels - numLightPixels) / 2, 1);
        } else if (newLightPixels=NUMPIXELS) {
        // Do some intense red blinking 
        if (now-lastBlinkPeriod > blinkInterval) {
          blinkColor = !blinkColor;
          lastBlinkPeriod = now;
        }
        for(int i=0;i

Next Build your circuit and print the attached case. I designed it a smidge small so scale it up by 3% when you print it and it should fir perfectly. (STL Files attached)

The attached visual schematic is using an arduino nano. If you wish to use the arduinoi micro pro you need to add a 3.3v regulator to power the boards VIN. otherwise the schematic is identical.

I tried to keep things as tight as possible and soldered most of it inside of the new housing. I also removed the majority of the pin headders from and soldered wires directly to it to make things a little more compact. Depending where you buy your components they may come with pin headers not yet soldered to save you the work :)

Its time to plug it in and test it out!

To set your minim and maximum distance edit these lines of the sketch

// The maximum rated measuring range for the HC-SR04 is about 400-500cm.

#define MAX_DISTANCE 100 // Max distance we want to start indicating green (in cm)
#define PANIC_DISTANCE 50 // Mix distance we red warning indication should be active (in cm)
#define PARKED_DISTANCE 60 // Distance when "parked signal" should be sent to controller (in cm)

These values control when your ring starts to light up, when its full and when it flashes red for the panic distance.. Play with them until the distance is right for your specific setup.