Universal industrial I/O controller with relays, analog/digital I/O, Modbus & OPC-UA support. Powered by Raspberry Pi.
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Features include:
- 8 digital inputs (3–30V)
- 8 relay outputs (SPDT)
- 4 analog inputs with calibration and filtering (mV to 10V, 4-20mA)
- 4 analog outputs (0-5V, PWM)
- Ethernet connectivity
- CE-ready enclosure with professional-grade labeling and documentation
Designed for rapid deployment, open development, and robust performance in edge control environments.
Subscribe to my project on Crowd Supply for launch notification
LinuxGizmos recently published an overview of SigCore UC in the context of its upcoming Crowd Supply launch, focusing on the system’s ability to bridge industrial I/O, open source firmware, and a software driven control model. Hackster also highlighted the project’s open approach to industrial PID control and modular I/O design.
In parallel, the project has been discussed on Coder Radio, and short capability overview videos are now live, showing the system running as a complete control and data acquisition platform rather than a collection of individual features.
At this stage, the hardware, firmware, and Control Panel software are all operating in near release form. The system has been running continuously in real environments for extended periods, and the core functionality is stable. No additional development is required to put a unit into service. Configuration, monitoring, PID tuning, and data logging are handled entirely in firmware on the device, with the remote Control Panel serving solely as the user interface.
Evaluation units are now available and beginning to move out. The current focus is on getting hardware into the hands of people who will actually use it, stress it, and apply it to real problems, not just look at spec sheets.
As coverage continues to accumulate, this log will remain focused on the technical side of the project, design decisions, real world behavior, and lessons learned along the way.
More soon, with data rather than adjectives.
The SigCore UC repo is now officially live on GitHub.
This is the full codebase for the SigCore UC platform — firmware, server, Control Panel application, drivers, update tools, and all the supporting hardware documentation. If you wanted to dig into how this thing actually works behind the panels, it’s all there now.
A quick breakdown of what’s in the repo:
.NET 8 Device Server running on Raspberry Pi OS (64-bit)
WPF Control Panel for Windows with full UI support for analog/digital I/O, relays, PID loops, calibration, and configuration
FRAM-backed persistent configs
Complete I²C device drivers (ADS1115, MCP4728, PCA9685, MCP23008/017, etc.)
SigCore messaging protocol
Update builder + launcher (automatic firmware/app updates)
Hardware drawings and documentation
Website assets and WebBridge backend for the device’s built-in web interface
The repo’s still marked as early-stage (revA hardware, pre-production software), but everything is functional and running on the current prototype boards. As work continues, all updates will push directly to GitHub so the history stays transparent.
Cleaning up the documentation now that the code is public
More detailed breakdowns of the hardware subsystem architecture
A demo video of the analog and relay subsystems in action
Preparing revB board fixes
Adding example automation scripts (Python + C#)
If you’ve been following along and wanted to see “under the hood,” now’s the time. Feedback, issue reports, forks — all welcome.
SigCore UC is built to be both powerful and open, so making the repo public is a big step toward that.
This week was all about getting the SigCore UC Control Panel into a shape that feels like a finished product — not just a test harness.
The interface is now a clean, touch-friendly dashboard that mirrors the hardware layout: relays, inputs, outputs, and live system functions all visible at a glance.
The software communicates directly with the SigCore UC hardware over TCP, automatically discovering the device, loading its FRAM-stored properties, and updating all I/O channels in real time.
Full control of I/O
Toggle all 8 relays with independent Normally Open / Normally Closed settings.
Monitor 8 digital inputs and 4 analog inputs with live voltage or sensor readings.
Adjust 4 analog outputs for voltage or PWM operation, including per-channel scaling and calibration.
Property dialogs
Each input, output, and relay has its own dialog with editable names, units, and parameters.
Properties are stored persistently in FRAM and reloaded automatically at startup.
Live operation
Changes take effect instantly — no restarts needed.
The Control Panel continuously polls and updates at user-defined sample intervals while remaining smooth and responsive.
PID control support
Direct access to PID loop properties.
Each loop has independent tuning parameters and setpoints.
Designed for heater control, feedback regulation, and automation loops.
Logging system
Integration with a MySQL backend to continuously log all channel data with precise timestamps.
Will enable long-term trend plotting and experiment archiving.
The Control Panel is written in C# (WPF) and communicates with the SigCore UC server over a JSON-based TCP protocol.
When launched, it:
Connects to the device (auto-discovery via mDNS).
Retrieves device properties and populates all channel groups.
Begins asynchronous polling and live updates.
Each group — relays, digital inputs, analog inputs, and analog outputs — runs in its own lightweight update loop, keeping the interface responsive even during heavy communication. All cross-thread updates are marshaled through the UI Dispatcher to prevent race conditions.
The architecture cleanly separates hardware control from presentation:
SigCore Server handles all device control and communications with the outside world.
SigCore Control Panel provides the user interface to monitor and control the server’s behavior.
Dialogs and property windows follow an MVVM pattern, making it easy to expand the system with new channel types or logging features later.
Decimal input bug
A stubborn issue blocked typing decimal points and commas in analog input dialogs. The culprit turned out to be an overzealous input validation filter. Fixed by handling input through double.TryParse() and bypassing locale restrictions.
Modal dialog behavior
Some dialogs occasionally dropped behind the main window. This was fixed by ensuring all dialogs are application-modal and always stay on top of the parent window.
Async initialization
The initial property load caused occasional UI freezes. Reworked to use background tasks (Task.Run) with Dispatcher.Invoke for updates.
Logging integration
The MySQL logger now runs independently but isn’t yet tied into the UI toggle. Batched insert handling is next.
The Control Panel has evolved from a prototype test tool into a professional-grade front end for the SigCore UC hardware.
It’s stable, visually clear, and fast — exactly what you want when you’re monitoring a live control system.
The really cool thing about the Control Panel Software is that it provides complete control of the device, just like a physical front panel. Every relay, input, output, and property is right at your fingertips.
You can operate it exactly as you would a hardware console — toggling relays, adjusting analog outputs, tuning PID loops, and watching live feedback in real time.
It makes...
Read more »SigCore UC on Coder.Show — Episode 630
In this episode, I talk with Michael Dominick about the goals and design philosophy behind SigCore UC — making industrial-grade control accessible and easy to integrate without the cloud
This release includes everything needed to manufacture and evaluate the SigCore UC board.
Included Files:
SCH_Schematic1_2025-09-26.pdf – Schematic exported from EasyEDA Pro
BOM_Main_PCB17_2025-09-09.xlsx – Bill of Materials
PickAndPlace_PCB17_2025-09-09.xlsx – Pick and place (XY) file for assembly
Gerber_*.gbr – Full Gerber layers for PCB fabrication
Drill_*.drl – NC drill files
FlyingProbeTesting.json – Netlist used for automated electrical testing
License: [MIT / CERN OHL]
Release Date: September 2025
The Silent Chip: MCP23017 @ 0x22
During initial testing of the SigCore UC board, all I²C devices came up clean — except for one. The MCP23017 intended for address 0x22 refused to respond.
Bus health was solid. Pull-ups were in place. Other devices (ADS1115, PCA9685, MCP4728, FRAM) were chatting happily.
But this one… radio silence.
After confirming that power and address pins were correct, I scoped the signals at the chip itself.
And that’s when it hit me like a like a splash of molten solder !!
SCL and SDA were reversed at the MCP23017.
That’s a brutal mistake for a device that only speaks I²C. With clock and data flipped, it's essentially deaf and blind on the bus. And there's no recovery from this one without physical intervention.
This was going to require precision:
Mapped the pinout:
Pin 12 = SCL
Pin 13 = SDA
On my board: reversed. Perfectly wrong.
Mask removed:
Used a fiberglass pen to expose copper on each pin's trace before the via.
Cut traces:
Clean slice just beyond the pads to isolate the misrouted lines.
Patch wires installed:
Swapped SCL and SDA using 30 AWG using motor winding wire.
Looks ugly but it was a clean fix.
Verified routing:
Continuity test between MCU and MCP23017 verified clean swaps.
No shorts, no cross-talk.
Power-up test:
Reconnected power, ran i2cdetect on the Pi…
0x20 0x21 0x22 0x40 0x48 0x50 0x70
It worked.....
Swapping SCL and SDA kills your afternoon.
This was one of those errors that slips right past the first check, the follow up, the triple check.... Easy to make. Hard to catch. Painful to fix.
But now the whole I²C bus is online and functioning. Lesson learned.
After months of circuit design, layout tweaks, and a few too many late nights staring at datasheets, the first batch of SigCore UC boards is here. Fresh from JLCPCB, they look clean. No visible defects, silkscreen is sharp, and all vias passed a visual inspection.
But we all know: the pretty green board is just the beginning.
Power traces were first on the checklist. With the Pi disconnected, I verified:
5V input to GND: ~2.5kΩ.
Realistic? Possibly. Low enough to triple-check, but high enough not to panic.
Current draw at startup (Pi powered through the board):
Brief spike to 0.7A, then settled at 0.31A idle.
Sounds about right. Nothing hot. No smoke. That’s a win.
Next up: relays and analog subsystems.
The mechanicals are ready, but I’m staggering component installation. This pass includes just enough population to begin bus testing and digital I/O verification.
I have seven devices mapped across the bus:
0x20, 0x21, 0x22, 0x40, 0x48, 0x50, 0x70
Everything responded except 0x22 — the MCP23017.
Could be:
Incorrect address pin wiring
Solder issue (checked, looks fine)
Damaged chip (possible)
Conflicting address (unlikely, but I’ll scope the lines)
The bus itself looks healthy. All other devices are talking and not throwing errors, even during extended run time.
Since the system is stable at idle, I’ve decided to let it burn in under light load overnight. I’ll monitor temp, current draw, and device response.
Next up on the checkout list:
Full relay bank test
Analog output verification (via MCP4728)
Digital input debounce behavior
High-frequency PWM generation test
Firmware handshake using SigCore protocol stack
And yes... I still need to fix that one non-responsive I²C chip. But the rest of the gang showed up to work.
Preview:
You never really know your board until you’ve stared at it under a magnifying glass with a multimeter in hand and a faint sense of dread in your heart.
But this one? This one looks like it’s going to be something special.
Another milestone down. My PCA9685-based PWM driver is now outputting a clean 250 Hz signal — and here it is on the scope:
This trace, captured on a Tektronix TDS 210, confirms that my PWM output is steady and accurate at 250 Hz with ~70% duty cycle. Each division is 500 µs, so we’re looking at a 4 ms period — and the high pulse lasts just under 3 ms, right on target.
Host: Raspberry Pi 4
PWM Driver: PCA9685 @ 0x40 (I²C)
PWM Output: 250 Hz, 70% duty
Scope: Tektronix TDS 210
Probe: 10x (CH2: 50 mV/div)
Coupling: DC
Trigger: Channel 2, rising edge
Bandwidth Limit: 20 MHz
This signal will ultimately drive an analog output stage via low-pass filtering — a lightweight DAC solution for the SigCore UC platform. Scope confirms it's rock-solid. Next step: verify analog voltage after filtering.
The layout for the SigCore UC main board is nearly finished. Most of the routing is in place, and the board is finally starting to take its final form. Here’s a look at both sides as it stands now.
Screw terminals for:
Relay outputs
Digital inputs
Analog inputs and outputs
Ground and 5V bus
Analog signal conditioning
Digital input protection and buffers
Relay drivers and flyback diodes
Voltage regulators and I2C expansion
40-pin header for the Raspberry Pi 4B, mounted through to the bottom
Mounting holes for enclosure alignment and Pi support
This is the working face of the board. All external wiring enters here, and components are grouped by function to reduce interference and simplify testing. The silkscreen is designed to align with the enclosure overlay for a clean, professional look.
The bottom side of the board faces downward inside the enclosure and carries:
Mechanical relays
Raspberry Pi 4B, mounted upside-down beneath the board
AC-DC power supply module
Mounting holes for board support and standoff clearance
The Pi's USB, Ethernet, and HDMI ports are not exposed directly through the enclosure. Instead, short patch cables will connect the Pi to panel-mounted connectors. This keeps the enclosure clean while maintaining full functionality.
The AC-DC supply (5V/10A) is mounted here as well, isolated from signal circuitry and well-positioned for airflow. Clearance, thermal, and safety spacing are being carefully checked as part of the final layout pass.
Complete routing of remaining analog and control lines
Review copper weight and trace widths for power handling
Confirm Pi port clearance and patch routing
Finalize relay trace layout and thermal reliefs
Add test points, label tuning, and silkscreen cleanup
Final DRC pass and export for fabrication
This is the most complete version yet — mechanical, electrical, and layout elements are finally lining up. I’m getting close to ordering the first round of boards for assembly and bench testing.
Edward
Jithin
smartroad
Andrew Bolin
Tijl Schepens