How to Use Ultrasonic Sensor HCSR04 with Zybo?

[goldyTW]

Hi everyone! I encountered problem when connecting ultrasonic sensor HCSR04 with pmod pin JA. Is there any reference for using that sensor with zybo? thank you

[kwilber]

According to the HCSR04 datasheet, it requires 5v for Vcc. The zybo reference manual shows, in section 16, pmods only have 3.3 v on pins 6 and 12. You would need a level shifter and a 5v supply powering the HCSR04.

[goldyTW]

thanks for answering

[kwilber]

Xilinx had a thread a few years ago that discussed this. They describe how you can get by without a level shifter.

There is also an old Digilent forum thread that discusses a similar project using a Basys3.

[zygot]

On 5/25/2019 at 12:33 PM, kwilber said:

you would need a level shifter and a 5v supply powering the HCSR04

Well, this statement is correct but... what would happen if you operated the HCSR04 at 3.3V? I've done that with pretty good results up to a few feet. The sensor has a small micro that seems fine with a lower operating voltage. I haven't tried to characterize the module at 3.3V as far as accuracy near the long distance of its range. There's no harm in experimenting as long as you supply 3.3V to the sensor power supply pins. Though somewhat limited these are cheap and nifty little sensors to lay around with. It would be swell if there was a version that allowed more control over the transmit characteristics and presented an different output signal, but hey, I encourage you to go ahead and play with them.