Embedded firmware for an e-bike drive unit that combines motor and gearbox: real-time control, electronic shifting coordinated with motor torque, and communication across the whole e-bike system.
An e-bike powertrain company is developing an integrated drive system that combines the motor and the gearbox in a single sealed unit, supplied to bike manufacturers together with the battery, display and controls. MicroBitDesign develops firmware for the system.
Why e-bike drive firmware is demanding
An e-bike drive is a real-time, safety-relevant embedded system that riders trust with their weight, their speed and often their daily commute:
- The rider is part of the control loop. Assistance has to feel natural: immediate when you push, smooth when you ease off, never surprising.
- Mechanics and electronics have to cooperate. When gears are shifted electronically, motor torque and the shift have to be coordinated precisely, so the gearbox is protected and the rider feels nothing but a clean gear change.
- Many devices, one system. Drive unit, battery, display and handlebar controls all talk to each other, and the system must handle every combination of states, including faults.
- Regulations and safety. E-bikes must respect legal limits on assistance and behave safely when a sensor or signal fails.
- Harsh conditions. Rain, mud, vibration, heat and cold, for years, across thousands of bikes.
What we work on
- Embedded firmware for the drive system
- Real-time control and coordination between motor and electronically shifted gearbox
- Communication between the drive unit and the rest of the e-bike system
- Fault handling and safe-state behaviour
- Testing and support as the product moves towards series production
Engineering focus
Deterministic real-time behaviour
Control loops, sensor processing and shift sequences run with predictable timing. Every millisecond of latency between the rider's input and the drive's response is something the rider can feel.
Coordinated shifting
A gear change under load is a carefully timed sequence: adjust motor torque, actuate the shift, confirm it completed, restore assistance. Doing that fast, smoothly and reliably, thousands of times per ride, is where firmware and mechanics meet.
Robust communication
The drive is one node in a system. Messages can be late, missing or unexpected, and the firmware has to stay in control and predictable regardless.
Safe by default
Every input is validated, and every fault leads to a defined, safe state. A drive that does nothing is far better than one that does something unexpected.
Ready for production
Firmware for a product shipped to bike brands has to be maintainable and updatable, and has to support production testing and diagnostics, not just work on a development bench.
How we work
A detailed, honest quotation up front, clear communication throughout, and delivery on time and within budget. We work closely with the client's mechanical and electronics engineers, because in an integrated drive, firmware decisions and mechanical design go hand in hand.
Technologies & disciplines
- Embedded firmware for e-mobility
- Motor and actuator control
- Real-time systems and sensor processing
- In-vehicle communication between system components
- Fault handling, diagnostics and safe-state design