Applying a Sensor Output Analog signal to a microcontroller

Good day to all,

Please I need help on how to get a stable 5V to my microcontroller. I want to convert the Output analog Signal from a sensor to digital Signal using the ADC peripheral in a microncontroller.According to the datasheet of the sensor,the Output voltage analog Signal has a range of : 0 to 5/10V. This means that the sensor can Output 0 to 5V OR 0 to 10V. My question is that is there a chip that i can use(or construct a small circuit) such that when the sensor Outputs 5V,I will get 5V from the Output of the chip and in case the sensor Outputs 10V , I will still get 5V from the Output of the chip.The constant Output voltage of 5V is important because my microcontroller maximum operating voltage is 5V.

I would be very grateful if somebody could put me through on how to resolve this issue.

Thank you for the usual support

Hello firstoption. To better help you you should provide more information. For example, you say that your sensor has two options for output voltage range. I don´t know which sensor is but sure it has some way of specifying the desired range. In the case you will use the 0-5V range is just to use the ADC alone. In the other case you need to scale the voltage output of oyur sensor. For this case you can use a resistor divider followed by an analog buffer, i.e. an operational amplifier capable of outputting in the range you want (0-5V). Here there are too many alternatives, I suggest you to use a single supply - rail to rail opamp, like OP191G for example (this is one that I know, there are too many others).

But remember, to better help you you need to provide more information about your problem.

Yosmany325.

Are you talking about two different sensor or a same sensor.
If it is two different sensor with the range of 0 to 10V and 0 to 5V and if you are going to connect at same point at different point of times then make a two inverting amplifier with gain of 1/2 & 1 (use jumper kind of thing to switch between two gains) at first stage and gain of 0 at the second. Connect the ouput of second stage to ADC.

If it is single sensor with a range of 0 to 10V then make a two inverting amplifier with gain of 1/2 at first stage and gain of 0 at the second. Connect the ouput of second stage to ADC.

If it is single sensor with range of 0 to 5V then instead of connecting directly make one non inverting voltage buffer connect the sensor to it and connect the output of buffer to the ADC.


Clear question with the connection details in your post would have reduced so many assumptions made in this and previous post. So kindly always be clear in what you need and then ask it.

hello, just use one transitor like bc557 in between controller and your sensor. connect your sensor o/p to transitor base through 1k resistor. connect the collector to ground. connect the emitter to your controller through 10k pull up resistor.

@welove8051 By doing this how he will read the 0 to 5V voltage range from sensor without ADC. Transistor will give you either high or low right?

Surendhar M said:

@welove8051 By doing this how he will read the 0 to 5V voltage range from sensor without ADC. Transistor will give you either high or low right?

Click to expand...

when the i/p is low the transistor( PNP) conducts to give low output at collector. when i/p is high the transitor do not conduct and hence you get high o/p through the pull up resistor.

That is understood but how he will measure the voltages between 0 to 5 (for example 1.5V). So it will not work out is what I'm trying to say.

from his post what i understand is, he want to interface that device as digital and not as analog.

Hai firstoption , you need a 5v( if your input voltage is 5 _10v ) and less than 5 v output voltage is same us input, this is the thing actually I understand from your post. If I am correct you can use a zener across the ADC line