1) easy .
3) 2032 batt.
Step 1: Material
dcv - displayer module * 1
Li battery (2032) * 2
battery holder * 2
HC - SR04 module * 1
mini * 1
UNO * 1 (for prototype use)
breadboard * 1 (for prototype use)
phone line box * 1
Step 2: Clean It All
Step 3: Fixed the Circuit on the Cover
fixed the SSD DCV - display module and HC-SR04
and mini on the cover with the hot glue gun.
Step 4: Test Circuit With UNO
maybe there are someone wondering about
how does it work:
because the mini have a max current limits.
so i use a dcv-displayer to independent the display
circuits from the mini.
the ping sent out signal... and travel...
and get reception t us later.
the mini convert the t domain to PWM domain.
and the dcv mudule convert PWM domain
to v domain.
and then the distance is on SSD now !
Step 5: Coding
i use the pin 6 (PWM one) to output the dist,
but you could use any one pin that support
for PWN as you like.
Step 6: Finished
the MAX dist is about up to 499 mm !
HAVE FUN !