Thrifty Bot Absolute Encoder with SPARK MAX

[EthanWall]

Hi,

I’m trying to use the Thrifty absolute encoder for reading swerve module rotation on an SDS Mk4i. But, instead of reading the correct value from the encoder, the SPARK reads either a random value or 0.

I have the encoder connected to the SPARK MAX through an adapter board (PWM signal connected to pin 6). I’ve also checked the encoder’s PWM signal with a multimeter and it changes correctly as the wheel rotates.

Any ideas? Thanks in advance.

[FritzG]

think you might be confusing PWM and analog signals here. Pin 6 on a spark max takes a PWM signal in (eg varies from x-y% duty cylce based on the position of the encoder), while the thrifty bot encoders output an analog signal (eg varies from x-y volts based on the position of the encoder)

edit:
definitely make sure you set the jumper to 3.3v as mentioned below

[Lexeo]

@EthanWall

Thrifty absolute encoder

The thrifty bot encoder works with an analog signal, and not PWM.

You’ll need to power the encoder at 3.3V (there is a jumper to do this). There is a 3.3V pin on the Spark Max. Then use Pin 3, and ground.

I’ve gotten this to work pretty well on a bench, and did something similar on our 2023 robot.

[EthanWall]

Thank you very much! Would the 5V amplifier on the breakout board let me run the encoder on 5V, or no?

[Lexeo]

This?
Yeah. That should work fine at 5V.

[nuttle]

Also, search here on CD – this topic has come up before, and the longer discussions are worth reading over.