Forums

Proximity sensors

Started by pozzugno November 14, 2014
I need to detect the presence of an object at the front of my PCB with a 
maximum distance about 10-20cm.

The behaviour would be similar to the proximity sensor found in modern 
touch-screen smartphones that let the OS switch off LCD backlight and 
touch detection when the phone is near the face during a voice call.
The proximity sensor in the phone detects an object at a maximum 
distance of about 5cm, I need to extend the range a little.

I understood there are many types of proximity sensors, but I'm not able 
to decide which to choose.  I need:
- low cost for 1kpcs
- small size
- it must work well in the dark

I don't need lux sensor, even if it seems some phones uses lux sensor 
for proximity detection.

Any suggestions? Thank you.
Il 14/11/2014 09:44, pozzugno ha scritto:
> I need to detect the presence of an object at the front of my PCB with a > maximum distance about 10-20cm. > > The behaviour would be similar to the proximity sensor found in modern > touch-screen smartphones that let the OS switch off LCD backlight and > touch detection when the phone is near the face during a voice call. > The proximity sensor in the phone detects an object at a maximum > distance of about 5cm, I need to extend the range a little. > > I understood there are many types of proximity sensors, but I'm not able > to decide which to choose. I need: > - low cost for 1kpcs > - small size > - it must work well in the dark > > I don't need lux sensor, even if it seems some phones uses lux sensor > for proximity detection. > > Any suggestions? Thank you.
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
<pozzugno@gmail.com> wrote in <m44h20$3cf$1@dont-email.me>:

>Il 14/11/2014 09:44, pozzugno ha scritto: >> I need to detect the presence of an object at the front of my PCB with a >> maximum distance about 10-20cm. >> >> The behaviour would be similar to the proximity sensor found in modern >> touch-screen smartphones that let the OS switch off LCD backlight and >> touch detection when the phone is near the face during a voice call. >> The proximity sensor in the phone detects an object at a maximum >> distance of about 5cm, I need to extend the range a little. >> >> I understood there are many types of proximity sensors, but I'm not able >> to decide which to choose. I need: >> - low cost for 1kpcs >> - small size >> - it must work well in the dark >> >> I don't need lux sensor, even if it seems some phones uses lux sensor >> for proximity detection.
ebay has thousands, of different type. This one uses IR, and had 15 cm range: http://www.ebay.com/itm/271604501562 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'.
>> Any suggestions? Thank you. > >Maybe you need some other info: >- I need to detect every objects (papers, plastics, hands, ...) > >
On Friday, November 14, 2014 3:44:24 AM UTC-5, pozzugno wrote:
> I need to detect the presence of an object at the front of my PCB with a > maximum distance about 10-20cm. > > The behaviour would be similar to the proximity sensor found in modern > touch-screen smartphones that let the OS switch off LCD backlight and > touch detection when the phone is near the face during a voice call. > The proximity sensor in the phone detects an object at a maximum > distance of about 5cm, I need to extend the range a little. > > I understood there are many types of proximity sensors, but I'm not able > to decide which to choose. I need: > - low cost for 1kpcs > - small size > - it must work well in the dark > > I don't need lux sensor, even if it seems some phones uses lux sensor > for proximity detection. > > Any suggestions? Thank you.
How about ultrasonics? There are lots of those on the web. George H.
On Friday, November 14, 2014 8:44:24 AM UTC, pozzugno wrote:
> I need to detect the presence of an object at the front of my PCB with a > maximum distance about 10-20cm. > > The behaviour would be similar to the proximity sensor found in modern > touch-screen smartphones that let the OS switch off LCD backlight and > touch detection when the phone is near the face during a voice call. > The proximity sensor in the phone detects an object at a maximum > distance of about 5cm, I need to extend the range a little. > > I understood there are many types of proximity sensors, but I'm not able > to decide which to choose. I need: > - low cost for 1kpcs > - small size > - it must work well in the dark > > I don't need lux sensor, even if it seems some phones uses lux sensor > for proximity detection. > > Any suggestions? Thank you.
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
klaus.kragelund@gmail.com wrote:

> 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 http://cgi.ebay.com/271668062849 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.
On Sat, 15 Nov 2014 06:17:20 +1000, <klaus.kragelund@gmail.com> wrote:

> 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
There not paying anything for the product - have a look - a 4093 and not much else
On 2014-11-14, pozzugno <pozzugno@gmail.com> wrote:
> Il 14/11/2014 09:44, pozzugno ha scritto: >> I need to detect the presence of an object at the front of my PCB with a >> maximum distance about 10-20cm. >> >> The behaviour would be similar to the proximity sensor found in modern >> touch-screen smartphones that let the OS switch off LCD backlight and >> touch detection when the phone is near the face during a voice call. >> The proximity sensor in the phone detects an object at a maximum >> distance of about 5cm, I need to extend the range a little. >> >> I understood there are many types of proximity sensors, but I'm not able >> to decide which to choose. I need: >> - low cost for 1kpcs >> - small size >> - it must work well in the dark >> >> I don't need lux sensor, even if it seems some phones uses lux sensor >> for proximity detection. >> >> Any suggestions? Thank you. > > Maybe you need some other info: > - I need to detect every objects (papers, plastics, hands, ...)
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. -- umop apisdn
On 2014-11-14, meow2222@care2.com <meow2222@care2.com> wrote:
> On Friday, November 14, 2014 8:44:24 AM UTC, pozzugno wrote: >> I need to detect the presence of an object at the front of my PCB with a >> maximum distance about 10-20cm. >> >> The behaviour would be similar to the proximity sensor found in modern >> touch-screen smartphones that let the OS switch off LCD backlight and >> touch detection when the phone is near the face during a voice call. >> The proximity sensor in the phone detects an object at a maximum >> distance of about 5cm, I need to extend the range a little. >> >> I understood there are many types of proximity sensors, but I'm not able >> to decide which to choose. I need: >> - low cost for 1kpcs >> - small size >> - it must work well in the dark >> >> I don't need lux sensor, even if it seems some phones uses lux sensor >> for proximity detection. >> >> Any suggestions? Thank you. > > Just an idea, since C detection is so cheap: differential capacitance detection?
It'd have to be pretty sensitive to detect "paper" and "plastics" -- umop apisdn