Agriculture · Ordinary People
He drove thirty minutes at five in the morning to read a thermometer for five seconds. Then Hiroki Tomiyasu built the thing that reads it for him.
Hiroki Tomiyasu · Biratori and Mukawa, Hokkaido, Japan
A liberal-arts graduate who had never written a line of code taught himself to build his own farm software, and now a 100-hectare farm in Hokkaido leans on tools that started with about 7,000 yen of consumer sensors and a winter of evenings.
The person and the place
Hiroki Tomiyasu came north to Hokkaido as a member of a regional revitalization cooperation squad, and started farming in 2020. He is now an executive at WFP Dacho Farm, about 100 hectares across the towns of Biratori and Mukawa, growing broccoli, soybeans, squash, and green onions.
The problem Hiroki cared about
The farm kept growing and the crew did not. 「1棟だと知れているんですが、20棟～30棟になってくると移動も含めて大変」, he told HBC. One greenhouse is a known quantity, but once it is twenty or thirty, it gets hard, the travelling included. The smallest chore was the worst of them. He described his old mornings to Metagri Labo: 「朝5時。エンジンをかけて車が暖まるまで5分。ハウスまで10分。温度計を覗く。『3.2℃か…大丈夫だな』。そのまま帰る。往復30分、確認5秒。」 Five in the morning. Five minutes to warm the car, ten to the greenhouse, a glance at the thermometer, 3.2 degrees, we're fine, and drive home. Thirty minutes round trip for five seconds of looking.
The agency moment
He is a liberal-arts graduate from Kanagawa with no programming education at all. In the winter of 2025 he started teaching himself Python, then started asking AI instead of a textbook. From day nine he posted one small app a day in public, which left him nowhere to quietly quit.
What changed, with evidence
He built a greenhouse temperature monitor out of consumer sensors for about 7,000 yen up front, running at zero yen a month, where commercial farm IoT services typically run several thousand to several tens of thousands of yen a month, by Metagri Labo's accounting. He built a remote window opener from a small controller and a motor over about two months, for 60,000 to 70,000 yen in parts. 「外注すれば100万円程度はかかるかもしれません」, he told Business Insider Japan: outsourced, it might have run about a million yen. He built a GPS work logger in roughly a day. He built a bot that carries Japanese into English, Indonesian, and Khmer for the people working the fields alongside him. HBC reports that a simple program takes him about fifteen minutes to get working, at roughly a tenth of what outsourcing costs.
Where it led
He keeps building for a reason that has little to do with money. 「自作すると、温度、操作時刻、開閉履歴、手動か自動か、失敗ログまで自分で持てます。」 Build it yourself, he writes, and you hold all of it: temperature, operating times, open-close history, manual or automatic, even the failure logs. The tools fit his fields because he is the one who knows the fields. Anyone wondering what their own version might be can start where he started, with the chore they keep driving out to do by hand.
The move worth copying
Seven thousand yen and consumer sensors. Build it yourself, he writes, and you keep the temperatures, the timings, and the failure logs. Anyone with a problem they understand better than any vendor could start where he started.
"チャットGPTで会話するような感覚でシステムを作っていける。トラクターの中で思いついて、トラクターの中から指示を出して、スマホがリモコンになってパソコンが勝手に作業しているみたいな" (You can build a system with the feeling of having a conversation with ChatGPT. I think of it inside the tractor, give the instruction from inside the tractor, and it is as if my phone became the remote and the computer is off doing the work on its own.) — Hiroki Tomiyasu, Sitakke (HBC Hokkaido Broadcasting)
Sources
Here is where this story came from. Go read the originals.
Curated by Good in Progress from the public record.
Sources last verified .
- note, Tomiyasu's own author page ↗
- note, Tomiyasu's own post, 'Build the system yourself and the field data becomes yours', May 2026 ↗
- Business Insider Japan, June 2026 ↗
- Sitakke, the web magazine of HBC Hokkaido Broadcasting, June 2026 ↗
- Hokkaido Shimbun, paywalled past the opening paragraphs, June 2026 ↗
- Nogyo AI Tsushin / Metagri Labo, an interview with Tomiyasu, Vol. 1: the 100-day app challenge ↗
- Nogyo AI Tsushin / Metagri Labo, an interview with Tomiyasu, Vol. 2: the zero-yen-a-month greenhouse monitor ↗
- Nogyo AI Tsushin / Metagri Labo, an interview with Tomiyasu, Vol. 3: running the farm's data through LINE ↗
AI-generated illustration inspired by this story.
