data from analog device ir sensor

[ps_anu]

Hi ...

how to get the data from analog sensor and pass via ble app

Thanks&Regards 

pspavi

[Ivan Herrera]

In the SDK there's an SAADC example that shows you how to read out a voltage on one of the analog pins. Depending on the application of the sensor you could use one of the existing services or create a custom BLE-service to read out and notify your data to the app. I personally used this tutorial to create a custom service.

https://infocenter.nordicsemi.com/topic/com.nordic.infocenter.sdk5.v15.0.0/nrf_dev_saadc_example.html

https://github.com/bjornspockeli/custom_ble_service_example

[ps_anu]

yes thank you ... i tried but  i am not getting the correct readings from sensor . i am getting like this ...

please check with this 

[ps_anu]

connections done between the analog ir sensor and nRF52840 ... BLUE (analog pin of sensor)

WHITE (Gnd)

GREY (Sensor supply)

[Ivan Herrera]

Your setup looks OK but the values you're reading are floating a lot, especially if you tried connecting the P0.02 to ground and it gave you the values you posted below. What is the max output voltage of your IR sensor, is it possible you've blown that analog input pin?

Try disconnecting the IR-sensor, changing NRF_SAADC_INPUT_AIN0 to NRF_SAADC_INPUT_AIN1 in the saadc_init function. This changes the analog-pin which is being sampled to P.03. Connect P.03 to GND and you should get values close to 0, connect P.03 to VDD and you should get values around 850. 

I just reproduced this example on my own DK and it's working fine so if you're still getting strange values you're probably dealing with a hardware issue. 

[ps_anu]

thanks... i am getting the value above 800... now how to get the correct value of my ir sensor

[Ivan Herrera]

Verify the max output of your sensor. If it's above VDD you need to add a voltage-divider so that you don't overdrive the analog pin, this is very important. 

Once you've verified that the IR-sensor can supply a safe voltage, you can connect the IR-sensor to the DK as you did before. (GND->GND, P.03->SENSOR-OUTPUT, ...)

Here's a link to Nordics SAADC documentation:
infocenter.nordicsemi.com/.../saadc.html

[ps_anu]

 my analog voltage sensor supply is 4.5 to 5v , its above the vdd , then can you explain about the voltage divider ? how to use