S
slow_rider
Guest
I'm using the Sharp IR proximity sensors that I'm sure a lot of people know about: Pololu - Optical Range Finders
These always have a range, for example the model I am using does 5cm to 80cm. It is not very accurate but I can calibrate it. The biggest problem with these devices is the output when the device in "under range".
Please take a look at fig.2 at the 5th page in the datasheet https://www.pololu.com/file/0J85/gp2y0a21yk0f.pdf, you can see how the output is usable from about 5 or 6cm and above. Under that, there's "aliasing" and an object located 2cm away from the sensor would generate the same output as if it's 20cm away.
So what I am basically asking here is how to figure out when the object is 5cm or under so I can output TOO CLOSE or a similar msg.
What comes to mind in sample pretty quickly so I can figure out the approx. distance the object moved and from the points gathered, calculate the slope which should be pretty constant if under range or value at point = derivative if in range. However this is not easy for an 8bit MCU
These always have a range, for example the model I am using does 5cm to 80cm. It is not very accurate but I can calibrate it. The biggest problem with these devices is the output when the device in "under range".
Please take a look at fig.2 at the 5th page in the datasheet https://www.pololu.com/file/0J85/gp2y0a21yk0f.pdf, you can see how the output is usable from about 5 or 6cm and above. Under that, there's "aliasing" and an object located 2cm away from the sensor would generate the same output as if it's 20cm away.
So what I am basically asking here is how to figure out when the object is 5cm or under so I can output TOO CLOSE or a similar msg.
What comes to mind in sample pretty quickly so I can figure out the approx. distance the object moved and from the points gathered, calculate the slope which should be pretty constant if under range or value at point = derivative if in range. However this is not easy for an 8bit MCU
