Mesure distance between two hacked HC-SR04's

Diode 1N5822 Schottky 40V 3A

40 colored male-female jumper wires

Arduino UNO

Ultrasonic Sensor - HC-SR04

Soldering kit

Resistor 10k

Arduino IDE

<html><body>Sorry in advance for my bad language or explanation. It's my first entry so You can cut me some slack :)Hi in this project I would like to show a unique way to measure distance using HC-SR04. To replicate this project You will need a computer with Arduino IDE, some soldering kit with soldering skills, some rectifier diode with around 0.5v drop and 10 kOhm resistor and HC-SR04. In my project I'm using 2022 version from AliExpress, but older revision will work just fine. This project was in the back of my mind for a long time and ChatGPT was telling me it was impossible, so I proved it wrong. Because of that I had write code by myself. I was a bit rusty but eventually I made version good enough to work. Step: 1. Modify the HC-SR04 On the 2022 revision there's pin hole called "t". That's "raw echo pin". On the 3 chip version this pin can be found on the middle chip, looking on bottom row of legs that's second pin looking from left to right side. To that pin we should connect the anode of the diode and add 10kOhm pulldown resistor. Finally to the cathode we should solder the connection wire to bridge connection to Arduino board. Step: 2 Prepare the master board Upload the master code to the arduino that You chose and wire up the modified HC-SR04. This board will be responsible for sending initial signal ,for waiting for any echo and calculate distance. The code was designed in the way to prevent most false positives in closed space environment. Step: 3 Prepare the slave board Upload the slave code to the other board and wire up the modded HC-SR04. On this side board will perform simple task. Arduino will constantly check for ultrasonic signal. Upon detection board waits fixed interval for air to clear up and emits echo back. The working principle. Designing and hacking around the intended use was doable. The crucial thing to start with is getting to know everything about this sensor. I highly recommend looking into my netography or doing your own research to fully understand how this board functions. The HC-SR04 module is very simple to operate. To use it as intended, you need to follow these steps:1. Pull the trigger pin high for 10 microseconds or more. 2. When the echo pin goes high, start a timer. 3. When the echo pin returns to low, stop the timer and calculate the distance.It couldn't be simpler, but for other use cases, it starts to get harder. Remember step 2? Because of that, the board can send more signals, and this step is tailored to a single board. That's why fellow YouTuber James Bruton used IR diodes to sync boards. The sync problem was hard to get around until I asked myself if I even needed it in the first place.Because I love to cut every corner and optimize the system, I explored every idea and analyzed what components were necessary. The diode was necessary because the raw echo signal is a 40kHz sine wave with a bit over 10V peak to peak, so the diode prevents reverse current and drops the voltage a bit. A pull-down resistor is used to remove a bit of noise. The modded version needs to work around the correct use. For that, the echo pin is completely forgotten and replaced by the raw echo pin. The 40kHz signal doesn't really pose any threat because the Arduino analog read function can be executed around 200kHz, which is about 2.5 times faster. <ol><li>"HC SR04 details working explanation | Ultrasonic sensor with arduino". YouTube, uploaded by: ETSolutions, May 9, 2021, www.youtube.com/watch?v=9DYaOu_kZQ8 Accessed January 13, 2024. </li><li>"Ultrasonic module reverse engineering". Hardware by Design, July 28, 2018, hw-by-design.blogspot.com/2018/07/ultrasonic-module-reverse-engineering.html Accessed December 20, 2023. </li><li>Emil's Projects &amp; Reviews: Making a better HC-SR04 Echo Locator. January 22, 2014, uglyduck.vajn.icu/ep/archive/2014/01/Making_a_better_HC_SR04_Echo_Locator.html Accessed December 28, 2023. </li><li>"Experimental Drone Positioning System". YouTube, uploaded by: James Bruton, March 21, 2023, www.youtube.com/watch?v=7r3OAkqaziI Accessed November 23, 2023. </li><li>ELECFREAKS. Ultrasonic Ranging Module HC - SR04. cdn.sparkfun.com/datasheets/Sensors/Proximity/HCSR04.pdf Accessed December 29, 2023. </li><li>Staff, LME Editorial. "How HC-SR04 Ultrasonic Sensor Works &amp; How to Interface It With Arduino". Last Minute Engineers, July 3, 2018, lastminuteengineers.com/arduino-sr04-ultrasonic-sensor-tutorial Accessed January 13, 2024. </li></ol> </body></html>

Mesure distance between two hacked HC-SR04's

Hack Your ultrasonic module to enable new capabilities beyond the stock!