IR Sensor

[jamespeach]

Guys,

I have a IR sensors and wish to achieve a accurate measurement in relation to distance?

Any way I could achieve?


Would it worth me using a different sensor, if yes I would need to get the reading to be displayed on a programming language called Python.

Thx

[Soeren]

Hi,

A Sharp distance sensor might do it, but you didn't reveal the distance you need?

What programming language you use have no bearing on the sensor you use.

[jamespeach]

Hi, need it to read accurate from 0cm to 55cm.

As the IR produce different reading I've take 700 reading at 10cm interval starting at 0 and worked out the average...

Is this method correct?

I was also advised to place a cap, (other post) but the sensor is fixed in a unit which connects to the pc via usb

Thx

[Soeren]

Hi,

No need for PM'ing me that you're awaiting my answer! If anything, it will only delay it.

Hi, need it to read accurate from 0cm to 55cm.

Sharp it is then.
GP2D12 is an excellent choice for this.

As the IR produce different reading I've take 700 reading at 10cm interval starting at 0 and worked out the average...

Is this method correct?

No.
Not with a Sharp at least.

I was also advised to place a cap, (other post) but the sensor is fixed in a unit which connects to the pc via usb

So you choose to ignore it?  Yeah, that'll surely give people a reason to keep helping you 

Place the darned cap and place it right at the power terminals of the sensor, not a distance away.
Please do write again if you still have problems when that cap is in place!

[jamespeach]

Hi,

No need for PM'ing me that you're awaiting my answer! If anything, it will only delay it.

Hi, need it to read accurate from 0cm to 55cm.

Sharp it is then.
GP2D12 is an excellent choice for this.

As the IR produce different reading I've take 700 reading at 10cm interval starting at 0 and worked out the average...

Is this method correct?

No.
Not with a Sharp at least.

I was also advised to place a cap, (other post) but the sensor is fixed in a unit which connects to the pc via usb

So you choose to ignore it?  Yeah, that'll surely give people a reason to keep helping you 

Place the darned cap and place it right at the power terminals of the sensor, not a distance away.
Please do write again if you still have problems when that cap is in place!

My teacher has already been given sensors called a Evolution IR Sensor, I have no idea what manufacture it is... so I've emailed the "Evolution" company and awaiting a reply.
 

If taking the average of the readings is incorrect, how do I approach this (calibrate)?

NO I do not choose to ignore it... the post did not state which cap rating... (which was going to be my next question)
 
The sensors which I have been provided are in a sealed unit, I will try this morning to dismantle them. If I can, which cap rating should I place at the power terminals?

Thank You!

[Soeren]

Hi,

My teacher has already been given sensors called a Evolution IR Sensor, I have no idea what manufacture it is... so I've emailed the "Evolution" company and awaiting a reply.

Sadly, a reply is not a given thing.
Why didn't you tell this in your very first post - having all the available info helps sometimes.

If taking the average of the readings is incorrect, how do I approach this (calibrate)?

The output should give a repeatable signal at first read. Averaging can be needed if objects a scattered around and you want a mean of the distance.

NO I do not choose to ignore it... the post did not state which cap rating... (which was going to be my next question)

Ah, well.

The sensors which I have been provided are in a sealed unit, I will try this morning to dismantle them. If I can, which cap rating should I place at the power terminals?

Around 20µF..25µF should give a reasonable clean signal.
Look for hidden screws first, if none are found, a vice and a steady hand is the easy way to crack a sealed plastic box open (glue it back together, but not until you have verified correct function).

[Spoil9]

sorry to thread jack for a sec...
Why are we putting caps on Sharp IR sensors? I have not used them yet but do plan on it some day (if I ever actually get around to building this robot instead of just buying parts for my parts drawer )

- Will

[Soeren]

Hi,

sorry to thread jack for a sec...
Why are we putting caps on Sharp IR sensors?

To "buffer" the power supply, to sort of brace it for the infrared LED that sucks current in short(/sharp Sharp) pulses.
If you don't, the supply line will be heavily modulated from these pulses and the LED won't be able to suck the current it needs anyway.

The capacitor lowers the impedance of the power line, to make it more "stiff" - and makes a certain amount of power available for short term supply - much like the water tank of a water closet has a reservoir to make a flush available (wouldn't work just with the supply pipe)

[Spoil9]

Okay, that makes sense. Just never heard that before. Thank you.