--- title: "Development of a Robotic Wireless Network for Underground Mine Rescue" url: "https://maker.wiznet.io/mayuri/projects/development-of-a-robotic-wireless-network-for-underground-mine-rescue/" markdown_url: "https://maker.wiznet.io/mayuri/projects/development-of-a-robotic-wireless-network-for-underground-mine-rescue/md" type: "UCC: User Created Content" author: "Jeffrey Wu" author_url: "https://researcharchive.vuw.ac.nz/xmlui/bitstream/handle/10063/7107/thesis_access.pdf?sequence=1" editor: "WIZnet" editor_url: "https://maker.wiznet.io/" original_author: "Jeffrey Wu" original_url: "https://researcharchive.vuw.ac.nz/xmlui/bitstream/handle/10063/7107/thesis_access.pdf?sequence=1" published: "2022-10-12" language: "en" hardware: ["WIZnet WizFi220"] likes: 10 views: 944 comments: 0 source: "WIZnet Makers (https://maker.wiznet.io/)" --- # Development of a Robotic Wireless Network for Underground Mine Rescue > The unknown and rapidly changing conditions encountered post-disaster in a mine environment pose huge risks to human rescue teams. Original author: Jeffrey Wu (source: https://researcharchive.vuw.ac.nz/xmlui/bitstream/handle/10063/7107/thesis_access.pdf?sequence=1) ## Components - **WIZnet WizFi220** x 1 ([docs](https://docs.wiznet.io/Product/Wi-Fi-Module/WizFi210)) ## Article 1 Introduction 1.1 Motivation The unknown and rapidly changing conditions encountered post-disaster in a mine environment pose huge risks to human rescue teams. HADES is a mine scout robot that can be used to safely and quickly determine the condition of mines post-disaster. HADES requires a communications system capable of streaming video data for tele-operation. Video transfer requires specific timing constraints to be met in order for the video feed to be useful to an operator. Furthermore, video transfer also requires significantly higher data-rates than simple text transfer. This raises the data-rate specification of the communication system. 1.2 HADES HADES is shown in figure 1-1 [1]. HADES offers rescue teams a fast and accurate means of assessing the mine conditions post-disaster. This presents mine operators with a bespoke costeffective device that is suited to unique conditions encountered in a mine disaster situation. HADES features no external actuators but implements a wide array of sensors and cameras that allows it to assess mine conditions. ![](https://maker.wiznet.io/upload/ckeditor5/704233387%5F1665585729%2Epng) Principal Objectives A critical feature of HADES that is required is the communication link between HADES and the outside world. This thesis focusses on the network design and the development of a wireless network for the HADES robot. The developed solution is termed HERMES, a wireless node system which HADES uses to communicate to the surface station operator. The problem explored in this thesis examines how a wireless network could be built between HADES and the outside world using small deployable nodes. The network system deployed faces several challenges summarised below. Literature Review Existing communication technologies that can be adapted for use in the HADES communication system are described in this section. Section 2.1 explores previously developed communications systems for HADES and emphasizes the need for a wireless solution. Prior work on the problem is detailed in this section. Wireless nodes by Heesterman An alternate investigation by Heesterman into this problem resulted in the design of compact pillshaped nodes with a flat antenna shown in figure 2-3 right [2]. Two nubs are added to the side of the node to prevent the pill from rolling when deployed on angled surfaces. The minimal size of the node designed by Heesterman was not only made possible by the small whip antenna, but also the small size of the AAA power source and associated electronics. This combination of battery source and a low-power transmitter allowed each node to be reduced in size to a length of 75 mm and a diameter of 40 mm. By abandoning the need for an upright antenna, the node is reduced in shape and the volume is further minimized compared to Molyneaux’s design. The deployment and storage mechanism of the nodes designed by Heesterman was not examined ![](https://maker.wiznet.io/upload/ckeditor5/704233387%5F1665585781%2Epng) Initial Design, Prototyping and Experimentation This chapter describes the testing and evaluation of various RF modules that suit both the RF and application-layer requirements as described in section 2.6.1 and 2.6.2. Section 2.6.1 described the requirement of an RF radio operating between 2.4 GHz and 900 MHz. Off-the-shelf components are selected for devices in this RF operating range and are narrowed down to three modules as detailed in sections 3.2 through 3.4. Two 2.4 GHz solutions and one 900 MHz solution are examined in detail. A comparative evaluation of these devices is outlined in section 3.5. Basic testing on a viable candidate RF module is described in sections 3.4 through 3.9. WizFi220 by WizNet (w/ ATMega2560 MCU interface) The WizNet WizFi220 is a 2.4 GHz module that features standalone network connectivity [41]. This solution is chosen due to its advertised long range and high output power with comparatively lower current draw of all devices as discussed prior in section 3.1. The WizFi220 features an ad-hoc mode. This feature is necessary in allowing the WizFi220 to allow units to freely form and connect to a network. This ad-hoc feature is discussed further in section 5.2.2. The application note states that the best range of the WizFi220 device was attained using a 2.5 dBi dipole antenna, reaching a distance of 620 m with the ping utility [42]. ![](https://maker.wiznet.io/upload/ckeditor5/704233387%5F1665585869%2Epng) HERMES Electronics Design 4.1 Overview This chapter discusses the hardware of the HERMES node, including the PCB board, circuit design, and microcontroller selection. The HERMES node hardware features a stacked PCB design. The top PCB board is discussed in section 4.2. The bottom PCB board is discussed in section 4.3. Section 4.4 discusses two battery power solutions to meet the system power draw characteristics examined in section 4.3.5. Section 4.5 examines the node enclosure designed by Jones and Thompson in detail. The HERMES PCB design, battery placement and enclosure design is shown in figure 4-1. The HERMES hardware performance is summarized in section 4.6. ![](https://maker.wiznet.io/upload/ckeditor5/704233387%5F1665585919%2Epng) ![](https://maker.wiznet.io/upload/ckeditor5/704233387%5F1665585944%2Epng) The power consumption of the MCU varies depending on the application, clock-rate, and number of I/O pins and peripherals used. A maximum power draw estimate from the datasheet of this device is given in table 4-1. These figures show the maximum current ratings that the MCU operates at under normal operation. The system runs on a 3.3 V rail with 15 digital I/O pins used. Two dedicated transmission blocks are used for the UART and SPI split among 9 pins. 2 ADC pins are polled at 5 s increments and the power draw is considered negligible compared to constant the I/O drive current of the digital pins. The peripheral clocks are enabled due to the use of the UART and SPI modules. Conclusions and Summary of HERMES performance 8.1 Overview This chapter summarises the technical and network aspects of the HERMES wireless node system. Section 8.1 presents the hardware and network performance with respect to the specifications stated in chapter 2. Section 8.2 discusses the future work and improvements that can be made to the design to improve aspects of the HERMES node. Improvements mainly focus on the extension of the node hardware to account for user-operability and contingency management. Additional hardware improvements are briefly discussed in the event that future capabilities become available or in the construction of a further revision. This chapter is concluded with a summary of HERMES’ overall performance. ![](https://maker.wiznet.io/upload/ckeditor5/704233387%5F1665586065%2Epng) --- Source: https://maker.wiznet.io/mayuri/projects/development-of-a-robotic-wireless-network-for-underground-mine-rescue/