Wednesday, October 4, 2017

DxP Mask Meter (DxPMM) - Overview

Catchy new name for the UV Meter to help identify it a little more closely to its intended purpose.  It is, after all, not really a pure UV meter.  Part of its functionality does not even read UV but uses the incidental visible light emitted by the UV LED Array as a proxy for the UV light distribution (which seems to work just fine). 

My hope with this project is to have a relatively easy-to-use tool that simplifies the process of creating a mask for the Wanhao D7 as well as other DUP or DLP printers that are driven by NanoDlp.  Note that the meter can be used in two different ways when working with NanoDlp.  In its 'Dumb' meter mode you can use it as the designers of NanoDlp would have expected.  Namely by displaying a mask preview within the Mask Generation Wizard of NanoDlp and then using the meter to adjust cells.

Here is what one version of the process flow might look like:
  1. Connect the meter to a USB power supply using a mini connector.
  2. Use bluetooth on your computer to connect to the meter and start a capture to file session.
  3. Place the measurement grid on top of the LCD of your printer and secure it (you can use other guide methods).
  4. Display the full white calibration screen from NanoDLP.
  5. Position the Photoresistor meter probe to the first cell on the grid (bottom right) and press the button briefly.
  6. When a good reading has been obtained both LEDs will be lit and the screen will tell you to move to the next cell.  Move up one cell.
  7. When you are ready to move to the bottom of the next column to the right press and hold the button for a second.  This will send a line end.
  8. Repeat the above two steps until you have measured all cells.  Do this quickly or in a couple of sessions as readings from the photo resistor will change as it heats up!
  9. Turn off the full white display and close the terminal capture session.
  10. The output captured from the terminal session should be a comma separated stream of numbers of ten rows and ten columns.  Copy these to the clipboard.
  11. Open your copy of my NanoDlp UV Mask Calculator spreadsheet and paste the above values into the sheet named "Paste Here" in the space provided and follow the instructions at the bottom of that page.
  12. On the first sheet of the workbook you can now find the input that NanoDlp needs for a mask to be generated.  Copy it and then paste it into NanoDlp.
There is a lot more that can be done to refine the mask generated above but this is a broad overview of one version of the process.  You will need to do some tuning of the mask with the meter in the "Dumb" mode so you can measure and adjust cells within the NanoDlp Mask Generation Wizard.  Finally, you will want to print some calibration objects!

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