AI Engineer · Düsseldorf
Lars Müller
At University Hospital Düsseldorf I build Monti, an AI early‑warning system for cancer treatment. Patients wear a wristband at home, and I'm developing the model that learns what's normal for each of them. I also founded Benno, an AI agent on WhatsApp. Self‑employed tradespeople send it a voice message and get a compliant e‑invoice back.
Monti · University Hospital Düsseldorf
An early‑warning system for cancer treatment
Every three days or so, patients on intensive cancer treatment are back at the hospital for a check‑up. Nobody sees what happens in between. Monti aims to replace these visits with a wristband at home, and to do more: watch patients between visits, catch complications earlier than a check‑up would, and alert the hospital as soon as their readings drift from their personal normal. The research group ran a study with 79 patients. Their wristband data showed severe complications, and infections up to two days before they were clinically diagnosed.
- Role
- I build the study platform and the detection system, from the model to the alert threshold.
- Deployment
- Patients in Düsseldorf and Aachen have been wearing the wristband since 2025. Each hospital has its own installation with an audit log, role‑based access control and daily backups.
- Data
- Heart rate, oxygen saturation, HRV, ECG, temperature and movement from the wristband, plus questionnaires in the app.
Studies npj Digital Medicine 2023 · blood cancer European Heart Journal Digital Health 2025 · heart failure
Benno · Founder
Voice message in, invoice out
A plumber on the drive home sends a voice message: “Invoice to Müller GmbH, four hours of plumbing at 50 an hour, plus 180 euros for materials.” Benno turns it into line items, works out net and gross, and asks about anything missing. It waits for a “yes” before creating the invoice, and then the PDF lands in the same chat. It takes corrections and remembers customers. No app, no login.
- Legal
- E‑invoice under EN 16931 (ZUGFeRD, PDF/A‑3) with all mandatory details under § 14 UStG. Plus the small‑business exemption (§ 19 UStG), reverse charge, § 35a EStG, GoBD and DATEV export. From 2028, e‑invoicing between businesses is mandatory for every German company except small businesses under § 19 UStG.
- How it works
- Benno has about 30 tools, from invoices and quotes to cancellations and the customer list, and picks the ones each message needs. “Turn quote 12 into an invoice” is all it takes. Python, FastAPI, PostgreSQL; language models run only in EU data centres.
- Company
- Benno UG (haftungsbeschränkt), Düsseldorf, since April 2026, alongside my job at the hospital.
Projects
2026trainarobot.run
Watch a robot learn to reach its goal without hitting anything, right in your browser. Tune the reward, the learning rate and the lidar resolution, or build your own levels. PPO or DQN, on WebGPU where available. No account, no install.
2025BSI IT‑Grundschutz AI search
The BSI's IT‑Grundschutz compendium runs to more than 800 pages. This search answers questions about it in plain language and cites the module and paragraph behind each answer.
2022Bachelor thesis: Active Pre‑Training with Phasic Policy Gradient
In Ms. Pac‑Man, my agent scored higher without the pre‑training than with it. The pre‑training was the whole point of the thesis. Active Pre‑Training lets an agent explore a game first, with no score to chase. I combined it with Phasic Policy Gradient.
2021TurtleBot: autonomous navigation
As a student employee, I trained TurtleBots in the Gazebo simulator and transferred the learned policies to real robots.
Consulting
Consulting for select projects
Alongside Monti and Benno, I take on a few other projects, ideally ones built around AI agents. Got one in mind? Tell me about it on a free twenty‑minute call: book a call
AI agents that finish the job
I build agents that take a job from the first message to the finished document. They ask when something is missing and make nothing binding without a “yes”. That's how Benno works.
Testing AI agents
Simulated users talk to the agent, and a second model grades every reply. At Benno, this runs before a change reaches customers.
Software for regulated industries
I build in audit logs, role‑based access control and backups from day one. That's how Monti runs at two university hospitals. Each one hosts it on site, and the data never leaves the clinic.
