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  1. O

    Question about intensity control with PWM

    I've been using the low pass filter calculator at the site below below with various RC values and PWM frequencies. For example, a filter with R=1 ohm, C=1uF, and f=10 MHz varying from 0 to 5v has a settling time of 2.3 us which should be fast enough, but the peak to peak ripple is 0.12V which...
  2. O

    Question about intensity control with PWM

    I'm already using an MCP4922 dual channel DAC for the galvo signals, and planning to use an MCP4728 quad channel DAC for RGB. I was wondering if it's possible to modulate the laser fast enough with PWM to get some kind of variable brightness, but that has mostly been answered by the above posts...
  3. O

    Question about intensity control with PWM

    The modulation would be done without the RC filter to remove the factor of the slow settling time, and just use digital signals entirely. But this would probably still require a MHz range PWM signal, as I have gathered from your inputs. Also, I'm aware that DPSS lasers can't be modulated that...
  4. O

    Question about intensity control with PWM

    No worries, but my main question is still not answered. Basically if the galvo mirrors move a laser from point A to point B in X amount of time, how fast would the laser (TTL, not analog) need to be modulated with PWM so that the resulting line appears continuous and changes brightness, instead...
  5. O

    Question about intensity control with PWM

    Could you explain this in a bit more detail? I'm not sure how a 2 bit DAC would help in TTL modulation, which is only digital. But since I have an analog modulated laser, I'll probably just use a DAC that uses the I2C pins on the arduino, since those are not being used at the moment. (The other...
  6. O

    Question about intensity control with PWM

    I'm new to this forum and recently gained interest in laser shows, and I'm currently in the middle of experimenting with modulation circuitry with an arduino. A while back I got one of those 20kpps galvo scanner sets from ebay and an RGB laser module capable of analog modulation. Since the...




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