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Topic: Digital pins acting like Analogue pins for ADC (Read 210 times) previous topic - next topic


Apr 24, 2019, 10:33 am Last Edit: Apr 24, 2019, 10:44 am by MattyZeee
Hi all, a newbie here!

I'm busy using an arduino uno to make a "Blind" solar tracker for on top of a RC car. Currently, I am using all 6 ADC pins as I am managing the charging of a Li-ion battery (So I'm measuring voltage of the battery as well as the current being delivered to the battery) and the other 3 pins are being used by an accelereometer which measures the tilt of my solar panel. I am using a gps to find longitude, latitude, date and time (They use digital pins).

So now I have come short as I need ADC pins for my magnetometer to find due north. Is there anyway to convert a digital pin to an analogue in pin for ADC use?

Thanks in advance :)

Edit- I am aware I can find the direction using the GPS once the RC car starts moving by taking two co-ordinates readings and doing some maths, but if the car is still is there any way?


Is it an option to use a Nano (8 analog inputs)? Or a Mega (16 analog inputs)? Alternatively you can use an analog multiplexer (e.g. 74HC4051 or 74HC4067).

You can only use the analog pins for analog measurements; no way of converting a digital pin to analog.

If you understand an example, use it.
If you don't understand an example, don't use it.

Electronics engineer by trade, software engineer by profession. Trying to get back into electronics after 15 years absence.


Unfortunately I have to use the UNO, but I will definitely look into the multiplexes. Thank you!


Unfortunately I have to use the UNO, but I will definitely look into the multiplexers. Thank you!
Very unfortunate indeed, as the Nano is a vastly more practical form factor with exactly the same functionality as the UNO* (and two extra ADC inputs).

Adding the multiplexer would be at least as difficult as swapping to a Nano, both mechanically and in code - and for similar overall cost.

(*) Unless you need extra functionality from the 16U2, which is most improbable indeed - you likely do not even know about it.  :smiley-lol:


Apr 24, 2019, 07:23 pm Last Edit: Apr 24, 2019, 07:26 pm by PaulRB
Why not get a combined or separate accelerometer and magnetometer modules with i2c interface? Then you will need 5 fewer ADC pins. But also you need to free up A4 and A5 to use i2c interface.

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