For anyone wiring a Raspberry Pi into a field deployment or an industrial control loop, the tangle of breakout boards usually multiplies fast: one for analog sensing, another for RS-485, a third for extra GPIO. The CirkitScape Top HAT collapses those onto a single 40-pin HAT, combining a 12-bit ADC, half-duplex RS-485, an I2C GPIO expander, and a 4-port USB hub on one board that fits the Raspberry Pi 5, Pi 4, Pi 3B+, and Pi Zero.
The analog front end is built around a Texas Instruments ADS1015 with three usable input channels, configurable as single-ended or differential, plus a fourth channel reserved for reference-voltage monitoring. CirkitScape pairs it with a TLVH431 precision shunt reference and TLV906x op-amps for small-signal sensor work. Digital expansion comes from an MCP23017 running at the default 0x20 I2C address, adding 16 I/O lines across two 8-pin headers, with hardware address selection so multiple expanders can share the bus. A MAX485 transceiver handles RS-485 over the standard 3.3V, A, B, and GND pins, with an onboard 120-ohm termination resistor included for the end of a bus that can stretch up to 1,200 meters (4,000 feet). CirkitScape points at Modbus RTU, motor controllers, building automation, and multi-drop data logging as target uses.
Most of this hardware is already a known quantity to the mainline Linux kernel, which matters if you would rather not lean on vendor scripts. The MCP23017 is covered by the in-tree gpio-mcp23s08 driver, exposing standard GPIO character-device lines, and the ADS1015 has an IIO driver plus a Raspberry Pi device-tree overlay, so both chips can be brought up declaratively through config.txt rather than bit-banged in userspace. That said, CirkitScape ships the friendlier path too: Raspberry Pi OS compatibility, Python examples, and an automated setup script that enables I2C and UART, spins up a virtual environment, and pulls in libraries like smbus2 and adafruit-circuitpython-ads1x15. CirkitScape's documentation also points to minimalmodbus and pymodbus as the Python-side pairing for Modbus RTU work over the RS-485 interface, rounding out the software stack for industrial sensor and building-automation deployments. A no-code dashboard app is included for exercising the hardware before you write anything.
USB expansion runs at USB 2.0 speeds up to 480Mbps across four downstream ports, each with a current-limited switch rated at 500mA. The hub only comes alive once the bundled cable links the HAT's upstream USB-C port to one of the Pi's USB ports. Power is a 5V DC input with 3.3V board logic, and CirkitScape recommends a regulated 5V supply rated at 3A or more; high-current setups may need the Top HAT and the Pi powered separately.
The Top HAT sells for $45 (€41) direct from CirkitScape, ships from Alabama, and carries a 30-day refund policy.
