Applying blockchain technology to the Internet of Things (IoT) provides several advantages when compared to conventional systems, including improving the security by ensuring data integrity and accountability while enabling reliable control over many devices. However, integrating blockchain into IoT systems presents some challenges. A main challenges is designing a consensus protocol that is suitable for the IoT systems, where some devices may lack adequate resources, such as computation power. This paper introduces a novel consensus protocol called honesty-based distributed proof of authority (HDPoA) via scalable work. HDPoA is based on proof of authority (PoA) and proof of work (PoW), with the integration of PoW, HDPoA is able to realize the security advantages provided by PoW. This is achieved by utilizing the IoT devices’ collective computation power to mine and generate a new block.HDPoA was analyzed and then deployed and tested utilizing a purposely built testbed incorporating commercial devices that are low-cost. A performance measurements and evaluation along with the security analyses of HDPoA was conducted using a total of 30 different IoT devices comprise of Raspberry Pis, ESP32, and ESP8266. These measurements included energy consumption, devices’ battery life, devices’ hash power, and the mining time. The measured values of hash per joule (h/J) for mining were 13.8 Kh/J, 54 Kh/J, and 22.4 Kh/J when using the Raspberry Pis, the ESP32 devices, and the ESP8266 devices, respectively. The measured devices’ hash power, measured energy consumption, and the security analyses showed that HDPoA is secure and suitable for utilization into IoT-blockchain systems.