Error: EPERM, device closed, operation not permitted about mcp-spi-adc HOT 7 CLOSED

Thanks for your advice. I will adapt the formula to work with the photocell.

from mcp-spi-adc.

The README was updated mentioning that SPI must be enabled to use mcp-spi-adc. See 33ed477.

from mcp-spi-adc.

It looks like SPI hasn't been enabled. If a Raspberry Pi is being used, which appears to be the case, then SPI can be enabled with the raspi-config tool which can be called from the command line with the following command:

sudo raspi-config

Navigate to "5 Interfacing Options >> P4 SPI" and answer the question "Would you like the SPI interface to be enabled?" with "Yes", then answer "Ok", then answer "Finish".

If a fairly recent version Raspbian is being used a reboot should not be necessary. On an older version of Raspbian a reboot will be necessary.

After SPI has been enabled it should work.

This should be mentioned in the README.

from mcp-spi-adc.

Thanks for your straight answer!
I have enabled SPI through

sudo raspi-config

command and everything works great now.

from mcp-spi-adc.

That's good news 😄

I'll leave this issue open as a reminder that a note should be added to the README saying that SPI needs to be enabled before it can work.

One additional point, your program contains the following line of code:

console.log((reading.value * 3.3 - 0.5) * 100);

The formula (reading.value * 3.3 - 0.5) * 100 is for a TMP36 temperature sensor so it will need to be changed for a photocell.

from mcp-spi-adc.

Sorry to re-open this, but I am using an MCP3004 and am getting this when trying to read channels 0, 1, and 2. When reading channel 0 and 1, there are no issues, but reading all 3 produces this error.

from mcp-spi-adc.

@amcelroy I can't reproduce the error. Please open a new issue containing the following information:

• A description of the problem
• The complete stack trace for the EPERM error
• Minimal but complete sample code that can be used to reproduce the error

from mcp-spi-adc.