Info: Only assemble V3UP&V3DN or V4UP&V4DN - its important to set this to your device (GPIO Sensitive)

Mesh in credit card size: a stackable building-block system for Heltec-based Meshtastic nodes. (Other manufacturers and devices are planned)

This project is my take on a modular Meshtastic-compatible ecosystem in a credit-card footprint – small, clean, expandable, and designed for Heltec V3/V4 boards.

All PCBs are laid out so they can be stacked both mechanically and electrically, without flying wires or messy cabling.

There is a base card for Heltec V3/V4, and on top of that you simply stack function modules like “shields”. Typical modules include GPS, BME280 environmental sensing, and external notification cards (buzzer, LEDs, relays, etc.).

The modules all follow the same compact credit-card outline, so the whole stack stays slim and easy to fit into cases or custom enclosures.

Every module card includes M2 mounting holes so the entire stack can be screwed together – nothing wobbles, nothing is loose, even in mobile or outdoor use. All signals between base card and modules are pre-routed, so in Meshtastic you usually just need to adjust the GPIO pin assignments in software.

Whether you only need GPS for position tracking, a GPS + BME280 combo for environmental data, or extra notification modules for external alarms: just stack the cards you need, screw them together, configure Meshtastic – and your node is ready to join the mesh.

Stay tuned for new Modules