Recent content by piclt

  1. P

    closed loop DC motor speed control

    OR How ArduCAM use external trigger from a sensor - Arducam cameras specifically for use with microcontrollers and external trigger
  2. P

    closed loop DC motor speed control

    maybe try another camera...?? https://www.e-consystems.com/blog/camera/external-trigger-usage-of-see3cam_cu135-camera/
  3. P

    closed loop DC motor speed control

    Yes, that's the way to do it.
  4. P

    closed loop DC motor speed control

    Yes, I know a stepper motor would be better, but a DC motor AND Tacho generator had already been bought and fitted and even at this late stage of 43 posts later #43 the DC motor has not even been tested to see will it drive the projector at any sort of stable speed from the Laptop PSU with...
  5. P

    closed loop DC motor speed control

    You need to try the motor out with the speed control first. If it does not work then the sync does not matter because you have nothing to connect it to...?? You had no sync control on your old ac motor
  6. P

    closed loop DC motor speed control

    Why do you need it..??? Have you tested the Picaxe and mosfet speed control with the tacho feedback on the actual motor. Did it not work. ?? What was it not doing..??
  7. P

    closed loop DC motor speed control

    OK, If you reduce the speed by say 10% does the tacho volts go down proportionately say 10% or more. And similarly if you increase the speed 10% does the tacho volts rise in the same proportions.. You will need good linear response of tacho volts change for change in speed to give good control.
  8. P

    closed loop DC motor speed control

    These are all the thing you have to sort, you are at the machine and see it running. But looking at you picture in your earlier post there looks like a 3 to 1 ratio to the pulley on the tacho, that means the tacho is running at about 10000 rpm, what voltage is it outputting at that speed ...
  9. P

    closed loop DC motor speed control

    The spec sheet may be rated at no load OK, constant conditions. and it shows no load speed 3500 rpm. You earlier said you needed the motor to run at 1000 rpm when driving the film projector. What voltage did you need to get the motor to run at 1000 rpm. was it driving the projector. What amps...
  10. P

    closed loop DC motor speed control

    Thats why I say get the basics working first. Most people having their car re-sprayed will not worry about the detergent to use to wash their car when it gets dirty after the respray. They will have the bodywork prepared and actually re-sprayed, and have taken it out for a spin to get it dirty...
  11. P

    closed loop DC motor speed control

    Get it working with good stable speed control first. If that does not work sufficiently well and be reasonably stable then adding sync pulses will not help. I am not a film person, how is the film driven in the projector, are there holes along the side and a toothed wheel driving it, and you...
  12. P

    closed loop DC motor speed control

    Yes, and keep it simple at first to try and see how stable your DC motor is......
  13. P

    closed loop DC motor speed control

    Are we not trying to control 2 things here. Speed and Position. And to complicate matters we have to control the relative position while it is moving at speed. A bit like the old TVs, the horiz. or vertical oscillators had to keep running and keep in sync. There was a thing called flywheel sync...
  14. P

    closed loop DC motor speed control

    Are you using the XD3420, I looked up the spec. It is rated at 400mA at 12 Volts. Is the motor over loaded...??? .....Your measurement is over 3 times the rated current...?? Motor Type: XD3420. Low Noise Type: < 30dB. Operating Voltage: 6~20Vdc. (Nominal 12Vdc) No Load Speed: 3,500 RPM @ 12V...
  15. P

    closed loop DC motor speed control

    OK, the laptop PSU is a black box you cannot get inside so you will have to control its output going to the motor using mosfet and PWM Do you know what current (amps) the motor takes when running normal speed 1000 rpm driving the machine. When you know that decide the mosfet you are going to use...
Top