Axoloti_Laser_Interface

Adding some special outputs to Axoloti to control a Laser projector. X-Y on audio, 3 RGB outputs on PWM

X-Y amplification stage

Which output should we use?

• Audio output from the Jack. L to X, and R to Z
• LOUT+ and LOUT- to have balanced signal directly

Amplifier

We need to go to +/- 5V to have maximum range

Easy with LM072 op-amp

Balanced output

Seems we need balanced signals. ok. add another LM072 op-amp

Schematic

RGB output

PWM?

Filter and Amp needed?

Axoloti Patch

http://community.axoloti.com/t/pwm-output-pin-frequency/2776/11

Changing the PWM frequency and resolution:

static const PWMConfig pwmcfg = {400000, /* 400kHz PWM clock frequency. / 4096, / PWM period is 4096 cycles. / NULL, {{PWM_OUTPUT_ACTIVE_HIGH, NULL}, {PWM_OUTPUT_ACTIVE_HIGH, NULL}, {PWM_OUTPUT_ACTIVE_HIGH, NULL}, {PWM_OUTPUT_ACTIVE_HIGH, NULL}}, / HW dependent part.*/ 0};

pwmStart(&PWMD3, &pwmcfg);

palSetPadMode(GPIOA, 6, PAL_MODE_ALTERNATE(2)); palSetPadMode(GPIOA, 7, PAL_MODE_ALTERNATE(2)); palSetPadMode(GPIOB, 0, PAL_MODE_ALTERNATE(2)); palSetPadMode(GPIOB, 1, PAL_MODE_ALTERNATE(2));

Further info

Other Axoloty vector synths

https://www.akirasrebirth.com/

http://community.axoloti.com/t/axoloti-ilda-laser/5634/4

Technical help

https://en.wikipedia.org/wiki/Balanced_audio

https://www.electronics-notes.com/articles/analogue_circuits/operational-amplifier-op-amp/non-inverting-amplifier.php

http://sound.whsites.net/project51.htm

https://github.com/ffd8/dac_ilda

Other commercial hardware/Software

https://www.laserworld.com/shop/laserworld-shownet-network-interface

https://lzxindustries.net/products/cyclops

https://www.showeditor.com/en