Arduino Uno & HC-SR04 Range to Broad

Projects General Guidance
1

Hello,

My strategy was to use HC-SR04 sensors(connected to arduino) spread out every 2.5 inches to measure distance of items placed in each column(like a vending machine). My issue is that the range of sensor is too broad and the sensor cannot distinguish between columns(unless I use blinders which are not ergonomic).

Can someone suggest a more accurate sensor to use or different strategy all together. I see that laser tape measure are fairly accurate. Are there laser distance sensors that I could use in conjunction with the Arduino?

http://www.homedepot.com/h_d1/N-5yc1v/R-100061815/h_d2/ProductDisplay?catalogId=10053&langId=-1&keyword=laser+tape&storeId=10051#customer_reviews

Thanks

2

Hi ProgrammerDude,

You say each column is 2.5 inches apart but what is the max/min distance of the objects you wish to measure?

3

Thanks for the response.

Ideally 0-30cm. As close as possible to zero atleast as far as 30cm.

4

I cannot think of a sensor to cover your distance range as most get a bit unreliable at very short ranges.
Maybe someone else can suggest something?
I wonder if IR distance sensors would be better than sound as they should maintain a tighter beam for the longer distances.
As you have so many sensors so close together your probably going to get bleed over between them unless you scan through them.
Starting with all sensors off

do
turn one sensor on
wait for it to settle
take a distance reading
turn sensor off
move to next sensor
loop

A quick google finds this Products | Acroname interesting article and you can get arduino libraries for them if needed. Non of them can go all the way down to zero though the GP2D120 can manage 4 to 30 cm