50 lines
3.1 KiB
Markdown
50 lines
3.1 KiB
Markdown
# MicroEnv v2.x Board Designs
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This is a collection of [EasyEDA](https://easyeda.com/) schematics and board desgins for the MicroEnv v2.x's components.
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You can import the design definition files (`*.easyeda.json`) directly into EasyEDA via "File" -> "Open" -> "EasyEDA". The schematic is provided for reference in both EasyEDA and SVG formats; if you just wish to manufacture the boards, you only need to import the board definitions, then via "Fabrication" -> "One-click Order PCB/SMT" complete the order at [JLCPCB](https://jlcpcb.com). We order all boards in a black silkscreen with all other options as default.
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You can also see the designs directly on [OSHWLab here](https://oshwlab.com/joshuaboniface/microenv-2-0).
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The board design and images in this folder are © 2026 [Joshua M. Boniface](https://www.boniface.me) and licensed under the [Creative Commons Attribution-ShareAlike (BY-SA) 4.0](LICENSE) license.
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## Schematic
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The schematic is visible here in SVG format, and also as an EasyEDA definition in [schematic.easyeda.json](schematic.easyeda.json).
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The individual parts can be found, with their labels (`R1`, etc.) in the [main README parts list](https://github.com/joshuaboniface/microenv/tree/v2.x?tab=readme-ov-file#parts-list).
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## Board
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This is the main board of the MicroEnv which contains all components, with the SHT45 sensor on a long (40mm) "neck" to isolate it from the other components.
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The board is single-sided; there are no components on the reverse side.
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## Assembly
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Assembly can be accomplished either by hot-air reflow, or with a hotplate. The instructions are functionally identical for both except for the heating step (#5).
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The hot-air process requires the least tools, but is finicky and error-prone. The hotplate process is much simpler and more forgiving, but requires a suitable hotplate. We recommend using the hotplate method for any more than a very small number of MicroEnv sensors.
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1. Clean all PCBs thoroughly with isopropyl alcohol and paper towel.
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2. Carefully apply solder paste to each pad, with the following guidelines:
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* SHT45/SGP41: A very small amount on each pad, including the center pads; if you think it's not enough, it's just right.
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* Passive SMD components (R1, C1-3): A moderate amount on each pad focusing on the outer edges.
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* ESP32-C3: A very liberal amount on each pad for mechanical stability.
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3. Place each component on its corresponding pad using tweezers. Ensure the components are properly aligned and then gently press them down into the solder paste.
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**NOTE**: Placing each component after its corresponding solder paste can avoid accidental smudging.
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4. Heat the hot air station to 240C; no higher! Apply heat to the **bottom** of the PCB until all the solder reflows. Check carefully for any bridges or failed joins and gently reflow in the same way as necessary. **Never apply heat directly to the sensors themselves!**
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5. Perform electrical continuity tests to ensure there are no stray bridges.
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The MicroEnv is now fully assembled and ready for final testing/provisioning.
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