3btnBoard

Wireless Calipers (BleCaliper)

This repository is a working collection of code, PCB/CAD resources, and notes for a Bluetooth-enabled digital caliper project (BleCaliper). The goal is to provide hardware and firmware examples that let a digital caliper transmit measurements wirelessly (Bluetooth Low Energy) to a host device. Currently the code reads from Vinca calipers (cheap on Amazon). I believe the same hardware could be used on other brands; the code may just need changes to work with different models.

How does it work?

There are three buttons. Data is transferred to the host device (PC or mobile) via Bluetooth Low Energy (BLE) as keyboard presses.

• Press Button 1: Send the current measurement as a keyboard input (e.g., "12.34" or "0.567").
• Press Button 2: Send a "Tab" key to move to the next input field on the host device.
• Press Button 3: Send an "Shift + Tab" keys to move back in a form.
• Press Button 2 and Button 3 together: send Delete (backspace).
• There is also a power switch and built-in charging on the hardware.

Note: Button-to-pin mappings are defined in Code/BleCaliperRev5/BleCaliperRev5.ino (for example: Send = pin 9, Tab = pin 7, Back/Delete = pin 10). Verify the mapping in the source before wiring.

Current Status

• On-Hold: I have not touched this project since 2022. I may return to it in the future. I'm publishing this as-is for anyone interested in building or improving on it.
• Repository condition: The repository is unpolished; files from experiments and third-party samples are mixed together, names and folder layout are inconsistent, and some files may be duplicates.
• The early enclosures were made with FreeCad i then moved to Fusion360 for later versions. I believe the STL's are from the fusion 360 models. I havent looked into shareing the fusion 360 models.

Goal

• Build and document a small, BLE-capable interface for digital calipers so measurements can be read remotely by a PC or mobile device.
• Collect prototype hardware (Eagle/PCB files), sketches, and notes in one place so others can reproduce or improve the design.

Credits

• Third-party resources:
  • Adafruit — several Adafruit PCB/CAD projects and their READMEs/licenses are present inside Resources/. Those files remain under Adafruit's Creative Commons terms; please preserve their license/attribution when reusing.
  • Others who posted on this subject before 2022; examples include:
    • https://hackaday.com/tag/digital-calipers/
    • https://github.com/MakingStuffChannel/DigitalCalipers
    • https://www.youtube.com/@CuriousScientist

Quick Usage / Where to Look

1. Inspect Resources/ for PCB/Eagle files and their license.txt files.
2. Search for Arduino/PlatformIO sketches (*.ino, src/) and open them in your preferred IDE. If you do not find .ino files at the top level, look inside subfolders — some sketches may not be tracked or are stored in Resources/.
3. If you plan to build hardware, follow the included third-party README/license guidance and verify parts and footprints.

Security & Privacy

• Do not commit Wi?Fi SSIDs, passwords, private keys, API keys, or other credentials. If you discover credentials in tracked files or the Git history, remove them and rotate the affected keys immediately.

License and Redistribution

• This repository contains mixed content. Some items are original work and some are third-party (Adafruit) with their own licenses. See the included license.txt files in Resources/ for details.

Apology and Cleanup Offer

Apologies for the messy layout — this repo is a personal working archive. If there is interest, I may clean and reorganize the project. Open an issue or comment, and I will prioritize cleanup.

Safety & Liability

This project involves electrical hardware and modifications to measurement tools. Use at your own risk. The repository owner (Mechanic?Coder) and contributors are not responsible for any personal injury, death, loss, or damage to equipment, property, or data that may result from using the hardware, software, or instructions in this repository. Always follow safe working practices, use appropriate protective equipment, and verify designs before powering hardware. If you are unsure, seek assistance from a qualified person.