Embedded hardware and firmware for industrial machines
I design, build and fix the electronics inside industrial, marine and agricultural equipment, from schematic and PCB through firmware and field diagnosis. When a machine keeps faulting, I find out why. When a part your machines depend on is no longer made, I build a drop-in replacement and supply it in small runs.
- Engineer
- Kent Dieball, MSEE
- In business
- MicroFirm, since 1996
- Experience
- 35+ years, 6 patents
- Based in
- Stillwater, Oklahoma; remote work across the US
- Engagements
- Contract projects and part-time staff roles
Four ways I can help
Embedded engineering for OEMs
A complete product from one engineer: the circuit, the board, the firmware and the test fixture, with the documentation to hand it off.
- Industrial network devices: EtherNet/IP, CAN, J1939, NMEA 2000, Modbus
- Controls, data collection, and remote access to sensors and actuators
- Low-noise analog front ends and high-power electronics
- Field problems found and fixed on machines already in service
Obsolete-part replacement
When an I/O module, power supply or controller goes out of production, I design a replacement that fits the same place and speaks the same protocol, then build it in small runs with spares.
- Discrete I/O, power supplies, controllers and communication cards
- Matched to the original's connectors, mounting and network behavior
- Runs of 25 to 50 units, plus spares and ongoing support
Problem-machine troubleshooting
When a machine keeps faulting and nobody can find out why, I find the cause and fix it, remotely where possible and on site when needed.
- CAN, J1939 and DeviceNet dropouts and bus-off faults
- RS-485 and Modbus resets, EtherNet/IP timeouts
- Noise, grounding and intermittent sensor or I/O faults
- Long-term data logging of bus traffic and analog and digital signals, to catch faults that come and go
End-of-line programming and test fixtures
Fixtures that program and test every board or module coming off your line, so each unit ships verified and traceable.
- Automated firmware loading, serial numbers, keys and configuration
- Input, output, network-port and calibration tests with pass/fail limits
- A test record for every serial number, plus an operator procedure
- Updates as your product changes; spare fixtures for a second line
Four fixed steps, each priced before it starts
- 01 / Assess
Can it be cloned?
I review the interface, firmware, parts availability and test method, then give you a fixed price for the next step.
- 02 / Prototype
Build and compare
A replacement design, bench-tested against the original, then a few units trialed in your machines.
- 03 / Production
Small runs
25 to 50 units priced per unit, built and tested with a production test fixture.
- 04 / Sustain
Keep it running
Spares stock, repairs and firmware updates on an annual agreement.
Every firmware change runs about 200 automated tests on real hardware
Most small product teams test firmware by hand, and the bugs they miss show up in the field. On my current marine project, every change has to pass an automated release gate before it reaches the client: about 75 hardware-in-the-loop scenarios on a live CAN bus plus more than 120 unit tests, run unattended in about 45 minutes. It stops at the first failure.
The real device
The production unit on a live bus, not a software model.
A simulated machine
A CAN simulator plays the rest of the system: sensors, engines, and a marine display that acknowledges and silences alarms.
An independent observer
A listen-only bus monitor confirms that each message really reached the wire, so the device never grades itself.
A real browser
The setup screens are driven in a browser emulating Android and iPhone, checking what the user actually sees.
Console capture
Any crash or reset during a run fails the run.
Field reports become tests
When a customer reports a problem, its exact sequence becomes a permanent test.
- 1 clean source tree
- 2 unit tests
- 3 clean build, size check
- 4 signed update install + 18 refusal checks
- 5 full hardware-in-the-loop suite
I build the same kind of rig for clients: a test loop for your engineering team, or a fixture for your production line.
What I work with
| Microcontrollers | STM32 (F3, F4, G4, H5, H7), ESP32 (S3, P4, C3, C6), NXP Kinetis and i.MX RT, TI MSP430, Microchip PIC, Raspberry Pi CM4 |
|---|---|
| Networks | EtherNet/IP (ODVA, DLR) · CAN / CAN FD · J1939 · NMEA 2000 · Modbus RTU/TCP · RS-232/485 · LoRaWAN · MQTT · PMBus |
| Firmware | C and assembly, FreeRTOS and bare-metal schedulers, ESP-IDF, signed bootloaders and secure firmware updates, embedded web interfaces, LVGL touch displays |
| Hardware | Altium Designer, 2- and 4-layer boards, enclosures, production test fixtures, isolated 24 V industrial and 12 V vehicle I/O |
| Analog and power | Load-cell and millivolt signal conditioning, 4–20 mA, AC/DC power to 10 kW |
| Method | Written specs before code, staged fixed-price phases, hardware-in-the-loop tests, AI-assisted development for faster, better-documented delivery |
Recent and long-running projects
Replacement for an Allen-Bradley 1799ER I/O board
In design: a drop-in 10-input, 10-output EtherNet/IP board on STM32H5, built for ODVA conformance, with Device Level Ring support.
8.75 kW industrial power supply replacement
70 V / 125 A from 480 VAC three-phase, replacing an out-of-production unit, with an ESP32-P4 touch-screen controller and RS-485 networking.
Intermittent resets on a national sorting fleet
Diagnosing RS-485 communication faults on mail-sorting machines, with a staged plan: a fixed-price investigation first, so the customer never commits to the full correction cost up front.
Flow-monitoring gateway for a marine OEM
An ESP32-S3 device that reports strainer flow to the boat's displays as NMEA 2000 alerts, with phone-based setup and signed firmware updates. Every release passes the automated test rig described above.
Conveyor gap monitor for package sorters
Measures spacing and velocity of conveyor cars in real time to catch mechanical failures before they stop the machine.
Battery-powered vibration and temperature node
A low-power wireless sensor for rotating equipment, maintained through two hardware generations and many radio modules.
Precision sprayer control, about 15 years
Four control modules and their production test fixtures for an ag equipment maker; the module tester ran on the production line from 2011 to 2022. Several thousand systems are in the field.
Four-trailer weighing system
Custom load-cell signal conditioning to weigh four semi-trailers at once with continuous output over CAN.
Kent Dieball, MSEE
I started at Halliburton in 1990, designing controls for automated cement mixing and pumping equipment. At Oklahoma State University I built a 64-channel gamma-ray spectrometer for Sandia National Laboratories. Since 1996 I have run MicroFirm, a one-engineer firm that has delivered hardware and firmware to OEMs in oil field services, industrial automation, marine electronics and agriculture.
BSEE, Kansas State University (1990). MSEE, Oklahoma State University (1994).
Patents
- US 10,111,415Determining and depicting spray band length (2018)
- US 9,561,694Failure-tolerant tire inflation system (2017)
- AU 2015224502Controlling flow from individual nozzles (2015)
- US 8,523,085Individual nozzle control with PWM solenoid valves (2013)
- CA 2,102,649Cement mixing and pumping system for oil and gas wells (1997)
- US 5,289,877Cement mixing and pumping system for oil and gas wells (1994)
Tell me about the problem
A short description is enough: what the machine does, what is failing or missing, and how many units are involved.