Jan Grossmann | IoT Product Development

Selected work

Products in the field, not just prototypes.

These devices were built at Waste Digital, where I'm co-founder and Head of Development, with the R&D team I lead. On each one I was technical lead and owned the full development, from architecture and electronics to firmware and production. Try the simulations: they show the engineering problem each device solves.

01 / Smart waste · NB-IoT

Fill-level sensor

A battery-powered sensor that sits under the lid of a waste container, measures how full it is with radar and reports over NB-IoT. The data feeds collection route planning, so trucks only drive to containers that need emptying. It has to survive years in a metal box, outdoors, on a single battery.

System architecture, component selection and power budget
Schematic and PCB design, antenna integration in a metal environment
Low-power firmware: radar processing, cellular stack, secure OTA
Production programming, end-of-line test and field commissioning

● In series productionSTM32NB-IoTRadar sensingMQTTSecure OTA

simulationfill-level sensor1 s = 1 report

Fill38%

Battery3.61 V

Signal-97

Fill level38%

Report interval

Coverage

Estimated battery life 1.8 years

Illustrative power model. Picking the interval and planning for poor coverage is what decides whether a device lasts 1 year or 10.

02 / Access control · NFC

NFC smart lock

A battery-powered lock for shared waste containers. It opens only for authorized resident cards, checks access rights offline, and logs every opening for billing and pay-as-you-throw schemes. Cards are cryptographically authenticated, so a copied card does not work.

Architecture of the lock electronics, motor drive and power budget
NFC reader integration and AES-secured card authentication
Offline access lists synced over cellular, event logging
Years of operation on a primary lithium battery

● In series productionSTM32NFC readerAES-128Cellular IoTLow power

simulationsmart locktap a card

StateLocked

Openings1,284

Denied17

Tap a card on the reader

The handshake is a simplified illustration of mutual AES authentication, not the production protocol.

03 / Manufacturing

Production programming & end-of-line test

A device is only as good as the process that builds it. I designed the production line tooling for our devices: one station programs each board, tests it against limits, provisions its security keys, verifies it on the network and prints its label. A field commissioning web app then lets installation technicians activate devices on site.

Manufacturing planning and process implementation
EOL test station: limits, traceability, yield tracking
Secure provisioning of device identities
Field commissioning web app and hardware-in-the-loop test framework

PythonHIL testingTraceabilityDFMWeb app

simulationEOL test stationSN —

ResultREADY

Cycle time0.0 s

Inject a faulty board

Shift yield —

Label

Run a test to print a label

● In manufacturing

Wearable scanner

A compact, rechargeable wearable for field crews, with NFC and LTE connectivity. Designed for all-day use and rough handling.

NFCLTELiPo charging

out 12.00 mAreadback 12.00 mALOOP OK

Setpoint50%

Cut the wire

Industrial IoT power controller

Remote control of industrial equipment over NB-IoT, integrated with PLCs. Drives a 4–20 mA current loop and reads it back, so a broken wire is caught and reported instead of failing silently.

STM32NB-IoTPLC integration4–20 mA

LTE camera board

A connected camera board that captures images and sends them over LTE, for visual monitoring where there is no Wi-Fi or power grid nearby.

ESP32LTECamera

About these projects. The products shown were developed at Waste Digital s.r.o., where I am co-founder and Head of Development, by the company's R&D team under my technical leadership. They are presented to illustrate my experience. All rights to the products, designs and trademarks belong to Waste Digital s.r.o. The interactive demos are simplified simulations written for this website and contain no production firmware, keys or confidential design data.

What I can help with

From a one-hour review to a complete device.

Bring me in for the part you need. I have done each of these on products that ship, so the advice comes from production, not from a datasheet.

Technical consulting

Architecture and feasibility reviews, technology and component choices, and an honest view of production readiness before you commit budget.

architecture · feasibility · design review

Embedded firmware

Low-power firmware in C/C++, RTOS, connectivity stacks, secure bootloaders and OTA updates, plus the test automation around them.

C/C++ · RTOS · OTA · test automation

Hardware design

Schematic and PCB design, power and battery systems, RF integration, prototyping and board bring-up.

schematic · PCB · power · bring-up

Cellular IoT & NFC

NB-IoT and LTE devices that hold up in poor coverage, NFC access control, and device-to-cloud communication that survives the real world.

NB-IoT · LTE · NFC · MQTT

Manufacturing

Design for manufacturing, production process setup, programming and EOL test stations, supplier selection and cost of goods.

DFM · EOL test · NPI · supply chain

Complete products

For larger projects I bring in the team I lead (hardware, firmware, mechanical design and assembly), so the work can grow without changing contractors.

concept → series production

How a project runs

A clear path from idea to devices in the field.

Most hardware projects fail between a working prototype and a product that can be built, shipped and updated. I plan for that from day one. Click through the phases.

Ways to work together

Pick the scope that fits.

Hours to days

Consultation

A focused session or short review when you need a second opinion from someone who has shipped devices.

Architecture or schematic review
Technology and component choice
Power budget and battery life
Production readiness check

Weeks

Focused engagement

A well-defined piece of your product, delivered and documented, working alongside your team.

A firmware module or connectivity stack
A board design or redesign
An EOL test station
OTA and fleet tooling

Months

Full product

Concept to series production with my team covering hardware, firmware, mechanical design and assembly.

Requirements and architecture
Prototypes and validation
Industrialization and production
Field rollout and updates

About

Engineer first, with a team behind me when the project needs one.

I studied electrical engineering at the Czech Technical University in Prague and have been designing electronics and firmware since 2016. At Siemens Mobility I spent five years in railway safety systems, which taught me requirements-based testing and how to build things that must not fail. In 2022 I co-founded Waste Digital, where I lead development of our IoT devices and plan and oversee their manufacturing.

I'm hands-on in schematics and code, and I'm also comfortable in the rooms where budgets, suppliers and roadmaps get decided. I work in English and Czech.

2022 – nowCo-founder & Head of Development, Waste DigitalIoT devices for smart waste management, 2,000+ deployed across Europe
2018 – 2023System Test Architect, Siemens MobilityRailway Switch Guard control module; test strategy, product ownership
2017 – 2018R&D Engineer, Czech Technical UniversityMeasurement platform for aircraft and drone propellers
2016 – 2018Freelance hardware & firmware developerPump and lighting control system, power electronics
2014 – 2020BSc & MSc Electrical Engineering, CTU PragueElectrical machines, apparatus and drives

Contact

Building a connected device? Let's talk.

Tell me what you're working on and where you're stuck. I'll reply within a working day, and the first call is free.

Email me LinkedIn

Email: jangross4@gmail.com
Phone: +420 733 548 532
LinkedIn: in/jangross4
Based: Prague, Czech Republic