Proximity sensors

Il 14/11/2014 09:44, pozzugno ha scritto:

Maybe you need some other info:

- I need to detect every objects (papers, plastics, hands, ...)

On a sunny day (Fri, 14 Nov 2014 10:12:46 +0100) it happened pozzugno wrote in :

ebay has thousands, of different type. This one uses IR, and had 15 cm range:

It is a kit, for 2$79 free shipping you could order one and check what chip and circuit diagram. Or just get a thousand and negotiate half the price :-)

I really do not know if this works, but is is great fun to search ebay for 'proximity sensor'.

How about ultrasonics? There are lots of those on the web.

George H.

Just an idea, since C detection is so cheap: differential capacitance detection?

NT

And once again one wonders how 2.8USD with shipping is possible

How do they get that cheap shipping? If I were to ship to China, it would be 10 times more expensive just for shipping

Cheers

Klaus

I believe China subsidizes the shipping to expand the market. The trap with eBay and Paypal is if you want to send something back, they require a tracking number. It most likely costs more than the item is worth to ship something with a tracking number.

So consider anything you buy from China to be a one-way trip. I limit the purchases to $10.00 unless there is a very good reason to go higher. But that takes some convincing, and I often lose.

If you have a problem and can show the item is defective or does not meet their specs, some vendors will reimburse the purchase cost without requiring you to ship the item back. I give those vendors 5 stars. Others get zero and bad feedback.

Another problem that is starting to show up with American vendors is shipping everything with "Customs services and international tracking provided". An example is

where a speed wrench is offered for $3.99, but the shipping to Canada is $25.01, which is outrageous.

The charges are paid to Pitney Bowes, who has apparently taken a lock on the market. I think their charges are rediculous and I refuse to buy anything that goes through them. Same goes for UPS.

I lived in the US for 30 years before returning to Canada. I sometimes think of moving back to the states, but then I think of Asset Seizure from the police, DHS searching anyone within 100 miles of the border, and NSA which unfortunately works with Canadian security. Then I figure it is best to stay put.

There not paying anything for the product - have a look - a 4093 and not much else

It sounds like you want the impossible.

Ultrasonic or optical reflection has a chance to detect a sheet of cling film.

But I can't think of anything that will detect a mass of black-dyed cotton waste.

Actually I can think of one thing: whiskers.

It'd have to be pretty sensitive to detect "paper" and "plastics"

I've used one of these with reasonable success - make sure you get a decent distance ( a few cm) between the IR tx diode and the Silabs chip or else have some proper optical shielding.

Si1120 for Silabs (via Digikey)

Michael Kellett

I've found some parts from Vishay, for example: VCNL3020-GS08

Il 14/11/2014 09:44, pozzugno ha scritto:

If you projected a stripe pattern from one edge of the device, and received the stripe pattern from the other edge, so that the field-of-view only overlapped for objects in the 10-20 cm range, the analysis of an image for stripes (modulated at some carrier frequency, and in some not-obnoxious part of the spectrum, like infrared), would detect surfaces in the region of interest. It'd take two lenses, a driven bar display, and a linear diode array, plus some software.

As cheap in mass production as some kinds of optical mice...

they took years to get cheap though

NT

Ultrasonic detector. Look up PING