Photoelectric help

Discussion in 'The Projects Forum' started by Poetsmantra, Apr 29, 2010.

  1. Poetsmantra

    Thread Starter New Member

    Apr 29, 2010
    Hey everyone, I have a project in the works in which I am stuck on the schematic design. I will try to explain this the best I can...

    Project background information:
    What started this project was the simple fact that I became fed up with cleaning up beer bottles and pop cans after a social get together at my house.
    In my kitchen island, I built a bottle/can return chute for recylcables. This chute (4" PVC) goes down to the basement and ends in a large container to hold recycled cans.

    What I am trying to do here is design a simple system/circuit to tell me when the container is full. What I am going to use as an identifier is a "RED/GREEN/BLUE" combination LED. On this particular LED, I am only going to use the "GREEN" for empty, and "RED" for full.

    I would like to use some sort of photoelectric sensor to sit atop the container and measure it's empty/full state. When the can height passes the sensor, it is to change the led from "GREEN" to "RED." I don't have much knowledge in photoelectronics which is why I am here today.

    Also, I have a bright 2600MCD "BLUE" LED in which is going to light up the chute entrance when the door is pulled down to insert a can (will be triggered by a magnetic reed switch of some sorts).

    I would like to use a 12V 500ma power source for this project (same power source for both the sensor application and the lighting of the chute entrance).

    I have included some pictures of the material and project I am working with. I would appreciate any and all help!
  2. Bernard

    AAC Fanatic!

    Aug 7, 2008
    Do you really need to know if container is empty? Do you want to modify container or just put a beam break sensor near the top ? Just checked a bright white LED, 20 ma, 3.3V & a one cm light dependent resistor for range. In dimly lit room, reliably had 10 to 1 resistance change at 4 ft, easily detected with a comparator/ LED driver.
  3. Bernard

    AAC Fanatic!

    Aug 7, 2008
    I think this will work: R2 LDR, about 1 cm, 100Ω- .5megΩ dark. LM383, dual comparator, R3 depends somewhat on LDR selected, R4 5k to 100k pot. 600 Ω s may vary depending on LED ratings. Need information on LED. Last two 4.7 resistors are 4.7K ohm.
    Last edited: May 5, 2010
  4. Markd77

    Senior Member

    Sep 7, 2009
    LM383? Doesn't sound right to me.
    Apart from that it looks nice.
    If you put the chute going vertically and finishing a few inches above, when it is full the last can will block the bottom of the chute, which should be easy to measure.
  5. Bernard

    AAC Fanatic!

    Aug 7, 2008
    Markd77- right on, should have removed paperclip covering up the 9, it is LM 393. Maybe should have kept 383, added speaker & mic so we could haer the loud CLUNK as the cans fall.