# Recommendation for a Sensor to use

Hi,

For a little project I'd like to measure the fill level of a regular garbage bin (e.g. a bin such as this http://wgem.images.worldnow.com/images/7248037_G.jpg). I have a bit of experience with sensors in general, but not enough to know how to approach this project.

My first (and only) thought so far was to either use an infrared or ultrasound distance sensor, to measure the distance from the lid (where the sensor can be placed) to the top of the waste, and then through a simple formula calculate how full the bin is. An obvious issue with this is that garbage may not nicely stack inside the bin (e.g. on one side, waste will be closer to the lid than the other side), probably leading to some inaccurate readings.

Is there any kind of sensor I could use for this situation? For example, something that can take a few readings at an angle so the distance can be averaged out?

Any help is much appreciated.

Vitesze:
Hi,

For a little project I'd like to measure the fill level of a regular garbage bin (e.g. a bin such as this http://wgem.images.worldnow.com/images/7248037_G.jpg). I have a bit of experience with sensors in general, but not enough to know how to approach this project.

My first (and only) thought so far was to either use an infrared or ultrasound distance sensor, to measure the distance from the lid (where the sensor can be placed) to the top of the waste, and then through a simple formula calculate how full the bin is. An obvious issue with this is that garbage may not nicely stack inside the bin (e.g. on one side, waste will be closer to the lid than the other side), probably leading to some inaccurate readings.

Is there any kind of sensor I could use for this situation? For example, something that can take a few readings at an angle so the distance can be averaged out?

Any help is much appreciated.

The ultrasonic sensor(placed at the top): even if there is a hole as large as 10cm at a 11cm distance the ultrasonic will be still able to read the distance of 11cm

But if you want to go real fancy for no reasone: you could buy multiple ultrasonic sensors and place them on top
Or even multiple IR sensors placed on 2+ sides every 20 cm upwords.

Just a idea

Are you going to REQUIRE everyone who uses the bin to leave a smooth, level surface in the bin? When I use a bin, things are left in big piles of everything possible, from old clothes to cans and bottles that cannot be recycled to big blocks of plastic foam.

Does you bin operate differently?

Paul

Paul_KD7HB:
Are you going to REQUIRE everyone who uses the bin to leave a smooth, level surface in the bin? When I use a bin, things are left in big piles of everything possible, from old clothes to cans and bottles that cannot be recycled to big blocks of plastic foam.

Does you bin operate differently?

Paul

No, the bins would be used for everyday waste - so anything ranging from food waste to cardboard or clothes. I understand the difficulties with the scattering effect of non-smooth objects for a sensor; would this be an issue for an ultrasound sensor?

The only thing I really am interested in here is how full a bin is (or how much it weights)

prologikus:
The ultrasonic sensor(placed at the top): even if there is a hole as large as 10cm at a 11cm distance the ultrasonic will be still able to read the distance of 11cm

But if you want to go real fancy for no reasone: you could buy multiple ultrasonic sensors and place them on top
Or even multiple IR sensors placed on 2+ sides every 20 cm upwords.

Just a idea

This is sort of what I expected; as long as objects are within the detection cone of the sensor, it will always detects the closest object it sees? What if, for whatever reason, we have a bin where all the waste is stacked against the rear end, and the front is relatively empty; it would detect the bin as almost full, even though realistically there could still be plenty of space left. Now the relatively smaller garbage bins I want to deploy this sensor in shouldn't have as much as an issue with this as large containers, I wonder if there's any good solutions other than purchasing very expensive equipment.

Hi,
Put a spring loaded plate and switch in the lid.

When the rubbish rises to the top it will press up on the plate and activate the switch.

OPs bin.

Tom...

take a look in sensors section ..

Vitesze:
This is sort of what I expected; as long as objects are within the detection cone of the sensor, it will always detects the closest object it sees? What if, for whatever reason, we have a bin where all the waste is stacked against the rear end, and the front is relatively empty; it would detect the bin as almost full, even though realistically there could still be plenty of space left. Now the relatively smaller garbage bins I want to deploy this sensor in shouldn't have as much as an issue with this as large containers, I wonder if there's any good solutions other than purchasing very expensive equipment.

It doesn't need to be "expensive"... Ultrasonic sensors are starting from 1 usd or if you want waterproof ones still cheap, same for the ir obstacle detector, and use as many as you want.
And yes if the trash is stacked in the rear and there is a hole, it won't detect that hole very well using ultrasonic from above.
The solution to this as i said before is to use like lots of ir obstacle detector modules in every side of the bin at every 10 cm of height
I'll draw a scheme if you don't understand.

No it's ok, I understand it.

The lid pressure sensor as someone suggested would be of no use here; Id like to monitor the fill level of a bin on daily basis, not sense it only when its already full.

Using several ultrasound sensors could work; I'll look into that. Or alternatively, use only one and accept there will be a margin of error associates with the spatial distribution of waste inside the bin. Some error (about 10%) would be acceptable in my project so I can test and see exactly how reliable just one sensor would be.