Beginner's help request: About measuring resistance (using temperature sensor) (nRF51822-QFAA Rev3.)

[Yi, Changjae]

Hello guys.

I'm newbie to embedded programming.

I'm trying to make device that can measure temperature of other objects. I have a variable resistor. The resistor's resistance varies by temperature. I have connected the resistor to a board and the board is connected to one of nRF51822 pin.

Now what should i do? I want to know if I could get the resistance value of the variable resistor. is there some functions I can use? I am using S130_nRF51_2.0.0 for soft device and using SDK11.

• Also, I would really appreciate if you recommend some example sources that will be helpful to me to make this device

Thanks!

[Turbo J]

The circuit would depend very much on the type of the resisistor and the range and precisition required. You could try to use an ADC pin.

[Yi, Changjae]

it says the variable resistor is thermistor R25 100K'ohm'B = 3990 Kelvin

[TY]

• You'll find an ADC example in the peripheral folder of the SDK.
• Before you're connecting your variable resistor circuit to your board make sure you are not exeeding the specified voltages of the ADC pins

[TY]

en.tdk.eu/.../pdf-applicationnotes.pdf

Checkout Figure 1 that is the circuit you need

[Jørgen Holmefjord]

Hi,

You can find many examples showing how to use the ADC of the nRF51 on our GitHub page.

Best regards,

Jørgen