Ultrasonic People Counter MQTT

A system of two ultrasonic sensors to count the total number of visitors entering an area.

Arduino Starter Kit Materials:

2x Battery

2x Mini Breadboards

2x Ultrasonic Modules(HC-SR04 Ultrasonic Sensor)

12x Wires

Additional Components:

3x Wemos LOLIN D1 Mini ESP8266

2x Voltage Converters (Yizhet High Efficiency Voltage Regulator)

3x USB Cables (USB-A -> USB-B or USB-B -> USB-C, hardware dependent)

2x Battery Clip Connectors (JSGHGDF PP3 9V Battery Clip Connector)

Presentation:

MDF

Paint

All steps in setup must be completed twice for 2 sensors.

Connect your ultrasonic sensor to the breadboard as illustrated in the images.

Solder your WEMOS Chip to have female connection ports into 5V, G, D4 & D3.

Red wire goes into the 5V of the WEMOS Chip

Orange Wire goes into D3 of the WEMOS Chip

Black Wire goes into D4 of the WEMOS Chip

Green Wire goes into the G port of the WEMOS CHIP (Changed from black wire in physical model for clarity)

Connect the WEMOS into your computer via USB and run the appropriate code found in the linked Instructable:

https://www.instructables.com/Squirrel-Noise-Sensor-and-Map-of-Dundee-Botanical-/

Solder male wires onto the voltage converters at the 'out' end of the converter end (Red for positive, Black for negative). Then solder the battery clip connectors to the 'in' end of the board (Red for positive, Black for negative). Attach this to the breadboard with the positive wire connecting parallel to the 5V wire and the negative wire connecting parallel to the G wire. Once you have uploaded code you can remove the wire, and once a battery has been attached correctly (see image) the sensors will function remotely.

Casing created out of simple MDF wood cut-out, using a laser cutter, but the casing could be created with other materials such as cardboard. Dimensions of the box that will fit the kit inside are illustrated in the drawing. Wall thickness is 4mm and the bottom face of the box is missing.

Use the code for programming the sensors as provided in the Ultrasonic Sensor Programming Instructable.

Implement the code that subscribes to both sensors and interprets the information received from both sensors (Know internally as MonkeysensorL and R respectively). Upload this code to a third WEMOS board to allow the code to run via MQTT.

You will have to install certain libraries for the subscribe code to function, which can be installed via the library manager:

ESP8266WiFi.h – Enables WiFi connectivity for the D1 Mini.

MQTT.h – Facilitates MQTT communication.

Lines in the code referring to your wifi network will have to be manually edited to in order to function with your own network. This includes writing your wifi password where appropriate if it is not an open network.

Set up the two sensors 300mm apart on any surface - this distance will mean that passing movement detected will not exceed the 5 second ignore time and thus will function properly.

Now, all information received by the sensors will be interpreted by this code and will be uploaded onto the serial monitor. This information could be used in a fully functioning website that detects MQTT data, to show a count of people inside the gardens.