discrepancy in ADC reading.
On the input pin of the ADC, I measured it using a meter and read 1.54V but the ADC using SPI bus read 1.73V on Python code. There's a difference 0.2V. Is there anything I can do make them closer in reading?
Re: discrepancy in ADC reading.
Post a photo of your set up.
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mikronauts
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Re: discrepancy in ADC reading.
Best guess: (assuming code is OK)
Vref is too low on the ADC
Vref is too low on the ADC
lilzz wrote:On the input pin of the ADC, I measured it using a meter and read 1.54V but the ADC using SPI bus read 1.73V on Python code. There's a difference 0.2V. Is there anything I can do make them closer in reading?
http://Mikronauts.com - home of EZasPi, RoboPi, Pi Rtc Dio and Pi Jumper @Mikronauts on Twitter
Advanced Robotics, I/O expansion and prototyping boards for the Raspberry Pi
Advanced Robotics, I/O expansion and prototyping boards for the Raspberry Pi
Re: discrepancy in ADC reading.
Wow, you can tell by just looking at the picture.joan wrote:Post a photo of your set up.
Here it goes. A simple MCP3208 using SPI bus and Vref and Vdd tied to Pi's 3.3V. The pot it also tied to 3.3V and GND.
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- setup.jpg (41.43 KiB) Viewed 744 times
Re: discrepancy in ADC reading.
Vref is tied to Pi's 3.3V or 3.0V or whatever coming from Pi. Should be enough.mikronauts wrote:Best guess: (assuming code is OK)
Vref is too low on the ADC
lilzz wrote:On the input pin of the ADC, I measured it using a meter and read 1.54V but the ADC using SPI bus read 1.73V on Python code. There's a difference 0.2V. Is there anything I can do make them closer in reading?