## 1 Introduction  
Blockchain technology and the Internet of Things (IoT) are innovative technologies that are proving useful in industries as diverse as healthcare, automotives, finance, and supply chain logistics [1]. Security features including the decentralised nature of blockchain technology may address many cybersecurity issues in those respective industries. Aged care is one area that has recently started using IoT technology [2]. Aged care is primarily concerned with the health and wellbeing of elderly people. Lack of information transparency and data leakage in aged care could be life-threatening. The IoT industry uses low-powered microcontroller devices to develop ambient assisted living systems for the aged care industry, and potential data corruption or miscalculation can put lives at risk [3].  
The combination of blockchain and IoT technologies creates intrinsic benefits. Securing IoT end devices, which has been a challenge, is one of the key benefits. Blockchain technology has also benefited from microcontroller developments in the emergence of energy-efficient IoT devices and blockchain algorithms [4]. As low-powered microcontroller devices are portable and cost-effective, the IoT industry uses these microcontroller devices to develop and manufacture sensor-based IoT devices. Connected IoT end devicesmay process a large amount of sensitive sensor data, and it may be difficult to locate the source of a data leak in an event of a cyber threat [4].  
Blockchain technology may help ease the potential security and scalability issues of sensor networks. Blockchain technology adds another layer of security to data transmission, and makes it more difficult for cyber attackers to gain access. Additionally, it brings transparency to network access [5]. Alongside increasing the trust between parties involved, the blockchain can have other benefits, including the elimination of specialist gateways solely intended to secure IoT sensor networks [6].  
However, the integration of blockchain technology and microcontroller technologies can be a challenge due to energy consumption requirements [7]. Blockchains require significant computational resources, and thus consume additional energy in energy-constrained sensor devices, leading to higher temperatures. These higher temperatures may damage hardware devices and cause possible fire hazards. Fire hazards can put lives at risk. Understanding potential device temperature levels will contribute to preventing possible fire hazards. Additionally, the size and complexity of the blockchain network can also play a role in the energy consumption and temperature variations of hardware devices. A larger network with more nodes and transactions requires more energy to maintain and process [7].  
In this paper, we analyse the correlation between the blockchain energy consumption and temperature of low-powered IoT devices using Raspberry Pi devices and three commonly used blockchain algorithms. Additionally, we discuss how the temperature of IoT devices that process blockchain algorithms may possibly influence the energy consumption of low-powered microcontroller devices [8]. This paper will contribute towards developing more energy-efficient blockchain algorithms and IoT hardware devices. The paper is structured as follows. In Section 2, we discuss blockchain technology and its energy consumption. In Section 3, we look at related work. Section 4 outlines our methodology, while Section 5 presents our results and evaluation. Section 6 concludes the paper and outlines future work we plan to carry out.