Advice on building a circuit from an IR receiver to a modified mouse.

Discussion in 'The Projects Forum' started by avz10, Apr 17, 2009.

  1. avz10

    Thread Starter Member

    Apr 17, 2009
    20
    0
    I am busy converting an 8mm projector to capture single frames. I have started with this project, but am now stuck. I use a Eumig 610D projector.

    [​IMG]

    The design of the system incorporates the facility for single frame capture using a computer and appropriate software (cinecap). The software receives an on / off signal every time a frame of film is in the gate. (Using a camcorder to capture the images via firewire). This is sent to the software by a modified mouse via usband Cinecap forms an AVI file..
    [​IMG]

    As the film is transported through the projector at 3frames per second it causes the tensioner to trigger a microswitch.
    [​IMG]

    This signal is passed to the microswitch in the modified mouse which in turn tells 'cinecap' to capture a frame of film.

    The weakest part of the system is the microswitch triggered by the film tensioner of the projector. The micro switch does not always trigger, so I lose frames. Otherwise everything works fine.

    Someone then suggested to build a circuit using an IR receiver and two resistors.
    [​IMG] [​IMG]

    He then connected this small part to the mouse. He placed the reflective sensor (IR receiver) close to the shutter blades and by painting one of them white and the other two matt black he got a pulse once per frame.

    [​IMG] He put the sensor on an L shaped piece of strip board so it can just fit in and used a tie wrap to hold it to a mounting post nearby. The screw on the board is used to protect the detector. He commented that he is not dropping frames.

    I need a simple explanation what components I need and an easy diagram how to build the section starting from the IR receiver which will receive the impulse to the mouse which will be triggered.
     
  2. Darren Holdstock

    Active Member

    Feb 10, 2009
    262
    11
    The diagram is easy, but a simple explanation isn't enough to build a working circuit. Here's one anyway: You need a transimpedance amp and a data slicer, and the data you capture is referenced to the edges of the resultant output waveform, probably with some sort of delay fudge-factor.

    Before the TI amp can be designed you'll need to know the characteristics of the photodiode, specifically the sensitivity and junction capacitance. It's complicated a little by there being 3 analogue output levels: PD opposite a black vane, PD opposite a white vane, and PD open and exposed, and I'm guessing there'll be a lot of optical noise flying about from the projector bulb and film. I'd be more inclined to add an IR source (LED) between the vanes and the IR photodiode - it's a tried and trusted method.

    If you've access to an oscilliscope you could tweak the TI amp in a cut-and-try fashion in order to tune it.

    I'm quite intrigued by the mouse triggering. Is it an optical mouse that you've tapped your photodiode into?
     
  3. avz10

    Thread Starter Member

    Apr 17, 2009
    20
    0
    Perhaps my explanation is too long and tedious.
    I am not into electronics, but will be able to build a small circuit.
    I need help to build a circuit between an IR receiver and a modified mouse that will go to the PC via a USB. (The IR resceiver will be triggered by a rotating white blade)
     
  4. avz10

    Thread Starter Member

    Apr 17, 2009
    20
    0
    I have contacted the guy who initially built the circuit. I have seen the article that he used, but it is too confusing for me. This is the reference: http://www.jeffree.co.uk/pages/revmaster.htm
    I think he used this circuit.
    [​IMG]

    Now this is the first part of his circuit. Is this mainly for the IR, or what are the other parts?
    [​IMG]
    [​IMG]
    Or to make my life easier, what are the components used, comparing to the diagram?

    Same questions here:
    [​IMG]

    Any advice will help
    Thanks!
     
  5. jpanhalt

    AAC Fanatic!

    Jan 18, 2008
    5,671
    897
    Your question has been here awhile, so let me try to explain part of it. First, some of what you have posted does not seem to be related to what you want to do. Specifically, the schematic you posted is for a tachometer. It uses reflected IR to generate pulses that are counted with the microcontroller (16F84) and displayed on an LCD as RPM or some other function, such as cutting speed for a lathe. Your project seems much simpler.

    Refer to a redrawn portion from the posted schematic:
    [​IMG]

    The +5V and ground come from the mouse. R1 limits the current to the IR emitting diode (IRED) in the sensor device. As the reflected IR light hits the detector, it allows more current to pass. Voltage drop across R2 increases, and thus the signal goes from +5V (no current through R2) to some much lower value. NB: The part I picked for the schematic is an optocoupler. In your device, the IRED is not pointed directly at the detector, but rather is pointed perpendicular to it, so the detector sees only reflected light. In your picture, the sensor is the rectangular black device with 4 pins.

    The rest of the schematic you posted is not related to your project. I believe the mouse modification you show in your earlier post simply takes that "low" signal and treats is as a "click", i.e., switch closure, for one of the mouse buttons. At least, that's what the picture of the modified mouse PCB looks like has been done. You may need some interfacing, but it may also just work as is. You also show a small interface box. It is hard to know what is in it from the picture.

    The "mouse click" from the optical sensor then keys the camera via a program in your PC. R2 is probably a fairly high value, maybe 1K to 10K ohms. R1 is probably just 100 to 200 ohm. I could not find the part number you reference in the source of datasheets I use.

    Hope this helps. I have lots of 8-mm film I need put on optical disks. Please give us a follow up.

    John
     
  6. avz10

    Thread Starter Member

    Apr 17, 2009
    20
    0
    Thanks John

    This really helps and I understand it now. Will send it to the guy who built the circuit to get the values- still waiting for his reply

    Albie
     
  7. avz10

    Thread Starter Member

    Apr 17, 2009
    20
    0
    Just to see if I am heading the right direction:

    [​IMG]

    If I connect my multimeter to the mouse with the black cable connected to "E" and the red cable to "F" and the reading is +3.3 Volt, does it mean that E is the signal or F is the signal? Does this mean that E is 0 Volt and F is the signal?

    My next question is about finding a 5 Volt spot. "A" is connected to the red mouse cable and from what I have read is 5 Volt (??)

    And then some help with the Photo reflector. What would be similar products that I can try and found in South Africa?

    Thanks for any advice
     
  8. avz10

    Thread Starter Member

    Apr 17, 2009
    20
    0
    I am posting more photos of the mouse- perhaps that might help?!

    [​IMG]

    [​IMG]

    [​IMG]

    Thanks for any help, I'm a bit stuck
     
  9. Ruptor

    Active Member

    Apr 26, 2009
    44
    0
    Hi
    I like your original idea of the micro switch because it was simple and worked. All you needed to do was find a better way of mounting it so it is touching a more solid object. You should see if it could be mounted to trigger off of the gate as it drags the next frame in front of the lamp. The gate moves the perfs up, picks the film up and drags it down 1 frame at a time. It must be possible to mount the switch to click every time the gate pulses. Just a thought.
     
  10. avz10

    Thread Starter Member

    Apr 17, 2009
    20
    0
    Reuben in the Videohelp forum gave this advice:
    "I've been looking further at the Optek OPB608A. You can get a more up to date spec sheet for it here http://www.optekinc.com/datasheets/OPB608.PDF. As you found earlier the input from your mouse switch is normally at 3.3 V, the spec sheet for your mouse controller confirms this http://www.emc.com.tw/twn/database/Data_Sheet/PC/eKM8065.pdf. Because of this I think it is safer if the transistor part of the detector uses 3.3 V, while the LED part carries on with 5 V. Again there is an empty hole on your mouse where you can pick up the 3.3 V. "

    This was his advice, what I did:
    [​IMG]

    I started to build this afternoon, but might have burnt the IR receptor, as I do not get any signal when I wave white paper/use a fluorescent tube, switch the light of the room on and off, etc.
    I do get readings at the different points. I'm not sure if I did anything wrong. (The IR receiver is very cheap and I can easily buy another one)

    See what values I'm getting:

    [​IMG]

    Did I overheat the IR receptor with the soldering, or did I do something wrong?

    (Other site: Having Trouble with DIY Telecine (8mm) System - VideoHelp.com

    Thanks

    Albie
     
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