Pi Droid Alpha with HC-S04: affect of echo level convert?

Moderator: Steve

Pi Droid Alpha with HC-S04: affect of echo level convert?

Postby alanmcdonley » Wed Jun 15, 2016 9:24 am

I was just looking at 5v 3v3 Level Shifting Experiments and wonder if the Pi Droid Alpha Servo pin level shifting resister divider method affects the HC-S04 echo timing or accuracy?

When I had the echo going direct to the GPIO w/o the proper level shift, the distance readings seemed quite close to the mm. I did not re-check after I rewired the echo to go through the servo block (level shift protected).
alanmcdonley
 
Posts: 90
Joined: Thu Jul 23, 2015 10:50 am
Location: Boynton Beach, Florida

Re: Pi Droid Alpha with HC-S04: affect of echo level convert

Postby mikronauts » Wed Jun 15, 2016 10:00 am

the voltage divider should not affect the timing at all, for the ECHO pin, as the 3.3V GPIO decides high/low around the 1.66V mark, and the voltage divider turns the 5V into 3.3V.

Driving the TRIG pin through a voltage divider can be an issue.

Powering the HC-SR04 from 3.3V generally does not work.
mikronauts
 
Posts: 119
Joined: Tue Sep 16, 2014 6:58 pm


Return to Pi Droid Alpha

Who is online

Users browsing this forum: No registered users and 1 guest

cron