Sharp 2Y0A21 analog IR sensor

bueno2kk

Hello everyone! I'm new to the world of Bela, I'm doing a Doctoral Class.

I would like to know if for the Sharp 2Y0A21 Analog IR Sensor, do I need to do this procedure as indicated in the page. Because is analog I don´t think I need to do what is on the website link below, but just in case I wanted to be sure if do I need to use any resistors or it works straight into the analog input and if I need to do something with the code in Pure Data. https://learn.bela.io/tutorials/pure-data/sensors/distance-sensor/#the-code

giuliomoro

That sensor has analog output, just connect it to an analog input.

bueno2kk

Thank you for the fast response! I just tried it: if I provide 5V at a distance of 2cm, it does not work consistently; if I provide 3.3V, it works better but still gives negative values. Is it possible that the USB power isn't enough for Bela and gives erratic measurements?

Thank you for all the help!

giuliomoro

The datasheet says the supply voltage should be between 4.5V and 5.5V:

So you have to use 5V.

It also says the distance range is 10 cm to 80 cm

It then shows that it also works at shorter distance, though, as expected, it's non-monotonic:

Not sure what you mean by "negative values". If you are trying to measure distances in the 2cm range, this is probably the wrong sensor.