CNY70 and gasmeter

[johndoe2011]

Good morning
I have been working on the installation of the CNY70 on my gasmeter which has a reflective surface on the zero (not the six digit)
The link is made to one digital entry (impuls counter) of an IPX800 v3.
Everything works fine when i pass a small aluminium sheet under the CNY70 . The counter works.
When i put the CNY70 in front of the last digit , nothing works.
I have been playing with all possble positions of the sensor ( distance, orientation .....) and I am now wondering why is does not work.
My IPX800 v3 delivers 3.3V and NOT 5V . Could that be a reason for the lack of sensibility of the CNY70 ?
For those who have succeeded sensing with the CNY70, can I have some hints regarding the good positionning of the CNY70 in front of the windows .
Thanks a lot

[erisan500]

Post a pic of your gasmeter and I'll tell you a if it's possible to use a much more reliable way to count the pulses

[johndoe2011]

Hello erisan500,
Here is a photo of the gas meter. The inside of the zero is reflective ( wheel at the very right)
http://imageshack.us/photo/my-images/716/gasmeter.jpg/
Regards

[erisan500]

I just get "This photo has been removed"

[johndoe2011]

http://imageshack.us/photo/my-images/713/gasmeter.jpg/
loaded again

gas.jpg

[Bwired]

gas.jpg (74.62 KiB) Viewed 12468 times

[johndoe2011]

Hello,
Anyone can help me with my questions (first post) ?
Thanks

[Rene]

Not really an answer, but ... I am using a CNY70 to read my watermeter which has a small rotating disc and at some point a small reflective area underneath. This works flawless and is not very sensitive to how the sensor is positioned. How did you connect the CNY70 to the IPX800?

[johndoe2011]

Hello,
I connected the CNY70 using the following diagram

http://www.flickr.com/photos/igorgm/2486110065/

but instead of using an Arduino, I used an IPX800 v3 with :
3.3v instead of 5v
Gnd for both
First digital enrtry for the Ipx800 which is a counter

Thanks for your help!!

[johndoe2011]

Any News?

[Bwired]

The only thing i can think of is that the CNY is working a to low voltage for the small mirror in the 0?

[johndoe2011]

Thanks a lot
It means that the sensibility will increase if the voltage is increased from 3.3 to 5V ?
Do I keep the same 220 ohms and 47K resistors ?
Thanks

[erisan500]

Have a look here: http://blog.hekkers.net/2010/12/04/the- ... mment-5551

If you want to continue using the CNY70 you really need this: http://www.domoticaforum.eu/viewtopic.p ... y70#p30383

I tried your above schematic too in the past without success.

[jeroenc]

Light emitting diodes (which is inside the CNY70) emit light as a function of current, not voltage. Typically, these need around 20 mA.
The voltage drop across a LED is typically 0,6V depending on colar.
The datasheet for the CNY70 (http://www.google.nl/url?sa=t&rct=j&q=& ... Je1vnQ23GQ) mentions a drop of 1,25-1,6 V with an If of 50 mA.
Let's say drop = 1,2 V, If is 20 mA.
You have 3,3 V supply voltage, less 1,2 gives 2,1 V across the resistor. V=I*R --> R = V/I --> R = 2,1/0,02 = 105 ohm. Makes sense, the have a little more than double now (220) with a little more than halve the "normal" (5V) supply voltage. I'd change the resistor, no need for amplification circuits.
The datsheet also shows some diagrams relating to voltage, current and reflective surface distance.

Good luck!

[Rene]

I do not use an amplification circuit and it is working fine. Although I would have to check which resistor values and supply voltage I use.