Inspiration
Modern IoT runs on blind trust. When you trigger irrigation, open a valve, or start a pump in a rural area, you simply assume the action happened. But for mission-critical systems in agriculture, humanitarian operations, and off-grid infrastructure, trust is not enough.
We wanted to create a system where physical actions can be cryptographically verified, not just hoped for. That vision became DotActuate — using blockchain to prove that real-world actions truly occurred.
What it does
DotActuate connects blockchain smart contracts to physical actuators (pump, servo, motor), and to an on-device camera. When a blockchain command is issued:
The device takes a pre-action photo
Computes a SHA-256 hash
Executes the physical task (pump/servo/etc.)
Takes a post-action photo
Publishes the hash back to the blockchain
This creates the world’s first Proof-of-Actuation: mathematically verifiable evidence that the physical action happened exactly as commanded.
How we built it
Implemented a Polkadot/Substrate smart contract to store commands and proof hashes
Built an ESP32-CAM firmware that polls the blockchain, captures images, computes SHA-256 passively, and triggers actuators
Designed a secure proxy gateway to simplify blockchain RPC calls
Implemented pump and servo control with relays and PWM
Built a lightweight camera hash verification layer on the edge device
Created a dashboard for triggering commands and viewing proofs
Integrated real-world hardware: camera, pump, servo, relay, power system
We combined blockchain, embedded systems, and computer vision in one loop.
Challenges we ran into
Camera stability on ESP32-CAM (crashes due to power spikes and memory limits)
SIM800L GPTS module unable to handle modern TLS → required redesign of network layer
Memory limitations of ESP32 when streaming + hashing images
Ensuring reliable actuation when the pump or servo draws high current
Synchronizing blockchain block numbers with real-time hardware triggers
Creating a smooth demo despite physical hardware unpredictability
Accomplishments that we're proud of
Blockchain becomes far more useful when connected to the physical world
ESP32-CAM is powerful, but requires careful tuning to avoid brownouts
Verified automation requires off-chain + on-chain cooperation
Reliable IoT systems depend more on power engineering than code
Proof-of-Actuation has real potential for agriculture, emergency response, and infrastructure
Implemented a Substrate-based smart contract using the Polkadot SDK to store actuator commands and proof hashes
What we learned
Integrated c SDK to build a custom, energy-efficient, IoT-ready blockchain runtime for Proof-of-Actuation. Integrated Polkadot SDK to build a custom, energy-efficient, IoT-ready blockchain runtime for Proof-of-Actuation.
What's next for DotActuate
Expand actuator library: valves, irrigation systems, locks, motors
Build an SDK for developers to integrate DotActuate into their own hardware
Deploy pilot tests in rural farms & water systems
Eventually: a global registry of verified physical actions
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