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This partially assembled TDK-40 main board is the carrier PCB used in the 4 Axis Do-it-Yourself DRO Kit (TDK-40). It’s intended as a drop-in replacement for an existing kit, or as a solid foundation for advanced DIY builders who want to design their own enclosure, connectors, or custom wiring while still using the TouchDRO electronics and firmware.
With the appropriate ESP32 DevKitC module and TouchDRO firmware installed, the board becomes a full 4-axis wireless DRO adapter (encoder interface box) for most modern glass and magnetic scales that output 5 V quadrature signals (RS-422 or TTL). It uses the same 32-bit architecture and differential input circuitry as our TDA-4xx series adapters, offering comparable speed and performance.
What this board is for
- Direct replacement main board for the TDK-40 DIY DRO kit
- Platform for custom DIY DRO projects where you provide your own connectors, enclosure, and wiring
- Prototyping special-purpose DRO encoder interface boxes while reusing the TouchDRO app and firmware
Key features
- Supports up to four RS-422 or TTL quadrature encoder inputs for glass, magnetic, and other 5 V DRO scales and rotary encoders
- Integrated differential line receivers for robust RS-422 operation over long cable runs
- Tachometer input with wide frequency range for spindle speed measurement
- On-board power regulation and status LEDs for quick visual checks during setup
- Designed to work with the TouchDRO V3 Lite or Plus firmware running on an ESP32 DevKitC module
For detailed electrical specifications and pinout, see the TDK-40 Adapter Kit Manual.
What’s included
One TDK-40 main board, factory-assembled with all surface-mount ICs, passive components, and onboard LEDs installed.
What you need to supply
To build a complete DRO adapter, you will also need (not included):
- ESP32 DevKitC module programmed with the appropriate TouchDRO firmware (you can reuse your existing module or purchase our pre-programmed replacement module)
- Scale connectors (DB9 or your preferred style), wiring, enclosure, and mounting hardware
- 5 V power supply and compatible tablet running the TouchDRO app
If you prefer a ready-to-assemble kit that includes the enclosure, connectors, and pre-programmed ESP32 module, please see the 4 Axis Do-it-Yourself DRO Kit.