parkranger

Ultrasonic park distance LED lights for garage or carport.

Feel free to use this project as a base for your own projects AT YOUR OWN RISK!

Hardware

AVR micro-controller ATmega ATtiny84

• internal oscillator at 8.0 MHz (disable fuse CLKDIV8!)

Ultrasonic sensor module HC-SR04

• trigger on PA0 (SOIC pin 13)
• echo on PA1/PCINT1 (SOIC pin 12)

RGB LED

• 20 mA LEDs or 12V LED module without resistor, both with common anode
• red on PA5 (SOIC pin 8)
• green on PA6 (SOIC pin 7)
• blue on PA7 (SOIC pin 6)

Software

C code for Atmel Studio 7.0

• main loop triggers measurements
• different LED colors/brightness using PWM signals from timer0 and timer1
• timer0 overflows are counted using interrupt until echo is received to calculate distance
• echo signal triggers interrupt PCINT1 to start/stop duration counting
• switches between standby mode (LED almost off, 500ms between measurements, after 60 seconds without distance changes) and parking mode (LED shows distance, 100ms between measurements, after distance changes)

Electronic CAD files

Design files are made with KiCad. Gerber files for PCB production have also been generated.