Why customize EEVblog 121GW?
A rebuilt meter application runs on the real multimeter, including Bluetooth. Experimental firmware runs on the meter, including its Bluetooth functions.
A good fit for
Exact meter target. Open and rebuild a multimeter firmware.
Not the right fit for
A guaranteed plug-and-play recreation without the listed hardware revisions, accessories and software setup.
Compatibility
- Exact hardware
- EEVblog 121GW
- Software route
- Rebuilt C firmware and bootloader
- Where code runs
- Experimental firmware runs on the meter, including its Bluetooth functions.
- Development tools
- A laptop, a coding agent such as Claude Code or Cursor, and the tools listed in the guide.
- Evidence
- Source-reviewed creator project. Not hands-on tested.
Project ideas
- 01Open and rebuild a multimeter firmware
Getting started
- 01
Check your model and revision
- 02
Read the creator’s setup
An enabling experiment, not a new everyday feature. Do not rely on modified firmware for safety-critical measurements.
- 03
Start with a reversible test
Follow the linked project source before changing the device. Back up existing configuration, keep credentials private and stop if your hardware differs from the documented version.
Setup & technical references
Starter prompt
Help me plan open and rebuild a multimeter firmware using EEVblog 121GW. Read https://circuitdigest.com/news/eevblog-had-claude-code-rebuild-his-121gw-multimeter-firmware-in-c-overnight-and-it-works and its supporting sources first. Experimental firmware runs on the meter, including its Bluetooth functions. An enabling experiment, not a new everyday feature. Do not rely on modified firmware for safety-critical measurements. Confirm my exact hardware and required accessories, explain what is missing, and propose one reversible test. Ask before flashing firmware, changing privileged system settings or moving physical hardware.
Confirm your exact hardware before running device-changing commands.
Common questions
Where does my software run?
Experimental firmware runs on the meter, including its Bluetooth functions.
What should I check before buying?
Exact product. Stock and delivery region are not confirmed. Check exact model and bundle contents with the seller.
What are the setup risks?
An enabling experiment, not a new everyday feature. Do not rely on modified firmware for safety-critical measurements.
