Introduction: "Coronavirus Covid-19" 1 Meter Keep Away Alarm Gadget
بسم الله الرحمن الرحيم
This article is a demonstration of the use of the Ultrasonic Distance Sensor HC-SR04.
The sensor will be be used as a measurement device to build the "1 Meter Keep Away Alarm Gadget" for distanciation purposes.
The brain of this gadget is the wonderful ATTINY85 µController powered by a 3.7V Lipo battery.
The gadget integrates the TP4056 charger.
A GREEN LED lights if the measured distance from any object is greater than 120 cm.
A RED LED blinks if the measured distance from any object is lower than 100 cm with a lovely (noisy) beep.
A YELLOW LED blinks if the measured distance from any object is between [100,120 ] cm with a less noisy beep.
Many articles explain in details how the HC-SR04 works.
In a nutshell, The HC-SR04 Ultrasonic Distance Sensor is
1 - An Ultrasonic Transmitter – This transmits the ultrasonic sound pulses, it operates at 40 KHz
2 - An Ultrasonic Receiver – The receiver listens for the transmitted pulses. If it receives them it produces an output pulse whose width can be used to determine the distance the pulse travelled.
Step 1: Components Sourcing (BOM)
A few components are needed for this simple gadget.
These components are easily accessible from Amazon, Ebay or Aliexpress.
BOM : Bill of materials
Step 2: Schematics
The Open source Schematic Capture & PCB Design Software Kicad is used.
Step 3: Pcb Design
Kicad is used to route the board.
Step 4: PCB Assembly
A few components are to be soldered for this gadget.
Be careful and patient.
Step 5: Arduino Sketch
The arduino sketch uses the famous NewPing library to read the distance from the sensor.
The NewPing Library is Open Source and very well documented.
Step 6: Arduino Sketch Flashing
The flashing of code will use the Arduino Uno itself as an ISP programmer.
Hopefully, the "ATTINY85 ISP Programmer Shield " is used to flash the board.
Remark: Read the article "Yet Another ATTINY85 ISP Programmer Shield for Arduino"
Step 7: Enjoy
In this article we have gone over all the steps to produce a funny gadget that might be helpful.
A 15 seconds home made video shows a use case.
Need more information, put a comment.
الحمد لله رب العالمين