Fab Academy 2026 | Week 11 - Output devices Project - LM 393 Photosensitive light dependent resistor (LDR)

Week 08

Electronic production

Learning outcomes

  • Describe the process of tool-path generation, milling/laser engraving, stuffing, de-bugging and programming
  • Demonstrate correct workflows and identify areas for improvement if required
Week 3 cover

Assignment requirements

Group assignment

  • Characterize the design rules for your in-house PCB production process: document the settings for your machine
  • Document the workflow for sending a PCB to a boardhouse
  • Document your work to the group work page and reflect on your individual page what you learned

Individual assignment

  • Make and test a microcontroller development board that you designed

Progress status

Group work Done

In-house PCB production process

Individual work Done

Make and test a microcontroller development board

Documentation Done

Upload .zip with source files.

1) Introduction

Huge thinks TO-DO

  • Characterize the PCB fabrication
  • Mill copper traces wiht the CNC machine
  • Cut the board and test it
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2) Group assigment - Learning how to design a PCB production process

For more details visit Fab Lab Peru Week 8 Group assignment


Hybrid exploring and application

  • Lab structure
  • Signs
  • Warnings
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3) Individual assigment

Project idea

  • PCB Design - KiCad
  • Generate G-Code - intructions to CNC
  • Milling - V-bit engraving tool
  • Drill and cut

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Reviewing design
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Milling at CNC
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Milling at CNC
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PBC final product
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PBC final product
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Design 2 with Fusion
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Review design 2 at Lab
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Milling the design 2. we used a MonoFab SRM-20. It is a desktop CNC machine
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The MonoFab SRM-20 is adequate for small-scale production and versatile with a wide range of materials.
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We used a 1/32 milling cutter for milling the design 2. It is a 0,79 mm diameter cutter, suitable for precise cuts in electronics boards - PCB (Printed Circuit Board) milling process
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The calibration of the CNC machine is crucial for achieving precise results in PCB milling.
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PCB Milled
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Reviewing the product
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Accesories
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During this procees, we milled four Design 2 - PCBs on the MonoFab SRM-20, because we didn't know all the conditions and we were learning this new topic
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This is an operative PBC but we drilled and welded the sprats in the back. We were testing the design
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This is another operative PBC but we drilled, welded the sprats and make a mistake with the Xiao ESP 32 C3 routes
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Reviewing PCB. An ungly weld
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Reviewing routes and welds
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PCB during this learning process, not drill - desing 1
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PCB during this learning process, not drilling in and incorrect face- desing 2
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PCB during this learning process, not drilling - desing 2
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PCB during this learning process - Desing 1 & 2
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PCB final - the last version - desing 2 final
Milling at PUCP CNC

3.1) Additional individual assigment

Project production

  • Show schematic and PCB layout images
  • Clear labeled schematic
  • Explain microcontroller pins and connections (VCC, GND, I/O)
  • Schematic - PCB - Export - Fabrication files (screenshoots)
  • Preparation for production: export settings
  • File for preparation for milling
  • Soldering /stuffing documentation

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This additional assignment, we worked on Fab Lab UNI
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Design: PCB layout on Fusion 360 with connections
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Design: PCB layout on Fusion 360 screenshot
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Design references: Microcontroller pins and connections https://wiki.seeedstudio.com/XIAO_ESP32C3_Getting_Started/
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Milling: Roland MonoFab SRM-20 desktop CNC at Fab Lab UNI. MDF bed
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Milling: Copper-clad blank (35 µm Cu, 1.6 mm substrate). Cutting tools: a V-bit engraver (grey, flat tip) and a TiN-coated spiral drill bit (gold, for thruhole drilling)
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Milling: V-Bit 30° (0.1 mm tip) being inserted into the collet. Double-sided tape on the MDF layer. The spindle is positioned on XY origin
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Milling: coordinates (X: -9.40, Y: 141.84, Z: 40.11 mm), spindle speed control, and the toolpath. Speed set to 100%
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Milling: Initial 0.0 mm, Depth 0.15 mm, Tool V-Bit 30°–0.1 mm, passes 2
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Milling: toolpaths, trace isolation, board outline cut
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Milling: Aspire 2D view. CNC software
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Milling: PCB milled simulation
Milling at Fab Lab UNI
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Milling in progress:copper traces are visible as fine white lines. The V-bit is cutting. Isolation confirm correct Z depth
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Milling in progress: board 1 completed and board 2 processing
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Milling completed
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Milled completed: cleaning dust and reviewing the product. Aprox time 15 minutes
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Milling completed:clean cooper surface
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Soldering:02 female 7-pin socket headers
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Soldering: PCB view and two 1x14 male strip headers
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Soldering: 02 male 2-pin for VCC - 5v and GND connections
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Soldering: Designed PCB production process - VCC 5v and GND
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Soldering: D4, D5, D6 with GND and VCC
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Soldering: VCC, D0, D1 and GND; D2, D3 and GND and D4, D5, D6, GND and VCC
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Soldering: D7, D8, D9, D10 and 3v3
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Final designed PCB with a Xiao ESP32 C3
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The ERC (Electrical Rule Check) and DRC (Design Rule Check) processes are automated verification steps used during schematic capture and PCB layout to ensure your circuit is free of electrical faults and compliant with physical manufacturing limits
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The ERC process evaluates the circuit schematic, logic, and electrical aspects. With the schematic PBC, I checked: Unconnected pins, short circuits, floating nets, incorrect power supply connections, and incompatible pins
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The DRC process validates that your physical PCB layout, actual routing, component placement, and copper thicknesses, successful manufactured
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With the routed PBC, I checked: trace widths, gaps between components, boundaries, and routes
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DRC with the routed PBC
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Three final PCB for the project

4) Final project advance

Running

Explore devices

Band for runners

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Final project page

5) Final results

  • Linked to the group assignment page
  • Documented how you made the toolpath
  • Documented how you made (milled, stuffed, soldered) the board
  • Documented that your board is functional
  • Explained any problems and how you fixed them
  • Uploaded your source code
  • Included a 'hero shot' of your board

6) References files

We learn how to design, make and test a PCB. Files:

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