nanoDLP

Please check out my version of NanoDLP shield. Features:
- Embedded 12V->5V voltage converter (no need for external 5V power supply, only 12V one is required)
- Number of 3.3V, 5V, and 12V outputs to connect LEDs, fans, or other statically connected devices
- Standard Populu stepper motor driver
- 2 end stop inputs with pull-up resistor and filtering capacitor (optional)
- UART and I2C outputs with 5V<->3.3V converters (selectable voltage)
- Powerful MOSFET (>10A) to drive UV LED
- PWM output to drive a Fan (controllable blowing power)
- supports DS15B20 thermometer
- signal LED output
- 6 GPIO with pull-up, pull-down, and series resistors (all optional). Some of GPIOs support PWM, 1-wire thermometer
- buzzer (why not?)

Use cases:
- My printer has 4 HW buttons (up/down, emergency stop, UV LED On/Off) which take 4 GPIOs
- Fans are pretty noisy. It would be good to enable them based on temperature (measured with DS18B20 thermometer). Fan is connected to a PWM output
- I have 5V I2C LCD display. Having onboard 5V<->3.3V level converter makes things easier
- With this board I could get rid of several devices (arduino, CNC shield, 5V power supply, I2C level converter, UV LED MOSFET) and replace with just one shield.

Here is the schematics and PCB: https://easyeda.com/editor#id=1c84f9033 … 7bebf7602c

Here is how this looks like:

I could not fit all my needs into NanoDLP architecture. Since it is closed source I had to do a workaround. Instead of driving all this hardware directly from NanoDLP, I developed a 'firmware' that runs on the same RaspberryPI, and connected with NanoDLP via pseudo terminal. NanoDLP 'thinks' that it sends G-Code commands to a regular Arduino-based HW, while in fact these commands are processed on the same CPU in a separate process. This gives me an opportunity to process my hardware movement buttons, drive a fan, measure temperature, etc, without bothering main NanoDLP. Well, not all of these items are yet implemented.

Source code: https://github.com/grafalex82/nanodlpshield

Please share your thoughts on the device. Comments are appreciated.