Welcome to installment number twenty eight of the Design Challenge Project Summary series here at Element14. For those of you who are new to my content, in this series I chose a single Design Challenge project from current or past challenges, and write a short summary of the project to date. I am selective about which projects I summarize, as I want to highlight quality content. Unfortunately, projects that stall out, or get abandoned, are not chosen for summaries. Some project creators like to keep their own project summary going, and this series is not meant to overshadow those post, but to highlight each project from an outsider's perspective.
The subject of this installment is project Trackable Safety Helmet for Miners which was part of the Safe & Sound Design Challenge. The project’s designer, Mehmet Bozdal (mbozdal), said that his idea for a trackable safety helmet came to be after he learned of the extreme dangers and subsequent catastrophic disasters that claim dozens of lives every year for those on the front lines in the coal mining industry. Citing methane gas explosions as being the main cause of these disasters, his trackable safety helmet could help provide an early warning of high-gas levels, and also provide a trackable beacon in the event of an emergency.
In the project’s introductory post Mehmet posits that since methane gas is the main cause of the majority of coal mine explosions, he should focus a significant portion of his project on detecting and warning the miners of the pending danger. To do this, he needs to use a gas sensor that is capable of detecting methane concentrations as low as 5%, the minimum amount of the gas that is needed to promote ignition. With this knowledge he decided to use a Methane CNG Gas Sensor which is capable of detecting methane concentrations from 200 parts per million (ppm) to 10,000 ppm.
With a gas sensor chosen, Mehmet moved on to identifying more parameters that might alert the miners of worsening conditions within the mine shaft, and settled on building out the helmet to monitor several more factors including temperature, barometric pressure, and relative humidity as each of these metrics can change the point at which the methane gas could ignite. Other talking points covered in his introductory post include the addition of an RFID and IMU tracking systems, and implementation of a wireless communication link between the miners and a centralized system that would be able to aggregate all of the data collected from the miners helmets which could be analyzed to trigger a warning system, as well as reporting each miner’s position in the mine shaft.
The regulations for electronics in explosive environments was the focus for the project’s second update post, and it really helped bring into focus how dangerous this could really be. Many people believe that a spark is required for ignition, but in a gas-rich environment, something as simple as an overheating voltage regulator could trigger ignition if its temperature rises too high. Since this testing is quite time consuming, and very costly, Mehmet acknowledges that this type of testing is outside the scope of this project, and that he wanted to mention this type of testing anyway because if this project were brought to market, it would have to receive the proper testing.
“Simple device is defined 3.12 of the ANSI/ISA-RP 12.6-1987 as any device which will neither generate nor store more than 1.2 volts, 0.1 amps, 25 mW or 20 μJ." Simple devices can be used intrinsically safe and do not need to be approved. Therefore, LEDs, thermocouples may not need an approval. Unfortunately, my design is not in this category because it requires 3.3V or even 5V for sensors This means that this particular design should be tested in accredited testing laboratories. This is way beyond the aim of the contest and my capabilities (at least for now ),” he said.
With the basics of intrinsic safety covered, it was time to move on with the project and start thinking about how the safety helmet will communicate with different systems within the mine and on the surface as well. While wireless communication is the obvious solution here, but Mehmet has to contend with a lot of earth between the miners and the control room on the surface. To combat this, mines generally have two different communication systems (primary and secondary) that help negate this issue. Primary communication systems usually operate in the high frequency and very high frequency ranges while secondary communication systems work in the low frequency range so that its more powerful signal can punch through the earth and make its way to the surface. Visit the project’s 3rd update to learn more about the protocols that drive these systems and to find out which solution Mehmet chose for this project.
In the project’s fourth update, Mehmet gleefully informed us that his challenger kit had arrived after an unexpected trip to Canada. This allowed the project to move from the planning stage, to getting some actual prototyping work done. To get started, he selected the MSP432 and Wi-Fi boosterpack which would allow him to begin the initial configuration in the next update.
Admitting that he had never used a RTOS before, Mehmet moved into update 5 by challenging himself to learn the basics of TI-RTOS instead of taking the easy way out and using Energia, and Arduino-like IDE designed to make programming the MSP432 series easy. To get started he briefly showed readers how to configure a timer within TI-RTOS and how to write and configure a client on the CC3100 module. To finish up the post, Mehmet showed off a small “Ground Operations Center” program that he wrote to get the project started. He said that while this is just a basic socket program at the moment, he would add more features in the future.
After a two week absence, Mehmet returned with his sixth update post. This update was all about getting some sensors up and running, but as Murphy’s Law states, whatever can go wrong, will go wrong. While working on interfacing the sensor booster pack, Mehmet discovered that the sample code provided with the sensor pack did not work with TI-RTOS, despite the raw sample code working on its own. This was an issue because integrating the raw sensor code with the WiFi code, could cause timing issues which is something he would like to avoid. To remedy this, Mehmet decided to forego the TI sensor booster pack, and move to an Arduino to collect the sensor data he needs.
Update seven was short, but we saw more work completed on the helmet’s sensors, and the methods used to get data from the Arduino and MSP432 boards to the central computer. Mehmet's plans have the project utilizing each boards serial port to transfer data back to the computer, but this meant that he would have to add the UART driver to the WiFi code he wrote previously that connects the MSP432 to his wireless network. He includes this updated code as well as the TCP Echo source code at the end of this post. Finishing things up, mehmet said that he “has ordered a MSP430 for NFC communication. It will control the gate and send data to the computer via serial port.”
While the idea to use an arduino to capture the data was a good one at the time, Mehmet was not happy with the fact that the arduino’s size created a problem with being able to fit the project neatly into a safety helmet. This forced him to sit down and modify the Sparkfun MSP432 library to add in support for the ADXL345. With this complete, he was able to remove the Arduino completely from the project, and return to the original plan of using the MSP432 as the primary microcontroller for this project. This post was by far the most informative and well written so far, and I would highly suggest reading through it to learn more, and don’t forget to check out the source code Mehmet has included while you are there.
Update nine was not very long but it confirmed a major milestone had been completed Utilizing the helmet for access control was always a part of what this project set out to accomplish and this is what Mehmet focused on for this update Using a passive RFID tag in combination with the NFC Transceiver Boosterpack was able to write code that will send user IDs that have accessed a locked portion of the mine in an effort to generate accurate and up to date reports of which miner is at which location in the mine “It will read the tag and send the data over the serial port (the msp430 board convert serial to USB) to the Ground Operations Centre. The Ground Operations Centre will decide to doors open,” Mehmet said. “It registers the users who access the mining side so if multiple access occurred from a single tag it will deny the access.”
Mehmet continued work on the access control portion of the project in update ten, and showcased the system working with some new features in the video above. “The system is consist of NFC reader and NFC tag. In reality, short range RFDI system will be suitable hence NFC allows a few cms which is very short distance. However, the implementation of the system and how it works is completely the same,” he said. Mehmet included sample code, and a more thorough explanation of how this works in the body of the post, and I highly suggest checking it out, as it is quite informative, especially if you are trying to integrate NFC in your own MSP432 project.
One of the best moments in a design challenge project is when everything comes together and the first working prototype is debuted. In update eleven was dedicated to just this milestone, with Mehmet demonstrating the Smart Helemt V0.1. “I will demonstrate the Smart Helmet v0.1 I am always on the move so I struggle to find time but slowly going further. Let's summarise what have done up to now. I am using TI-RTOS. I stack the Wi-Fi booster pack to MSP432. Connect ADXL345 accelerometer and TMP102 using I2C interface. Detect free-fall, inactivity, and send all the data to Ground Operations Center over Wi-Fi using TCP/IP protocol,” he explained. “I coded Ground Operations Center using C and it still needs some modifications boosterpack is connected to Ground Operations Center via UART interface It controls the gate and doesn't allow unauthorised access and access without the helmet
Update twelve continued the demonstration, this time giving us a video walk through of what the helmet is capable of. Unfortunately, this is the point in the project in which we find out that the original plan to include a methane sensor was scrapped due to the fact that a portable version of the methane sensor that is required simply does not exist. This is because all of the small methane sensors utilize a heating element for analysis, and that heating element would cause the helmet to fail intrinsic safety testing, and would likely cause an explosion in a gas-rich environment. While this is a bummer, Mehmet did not let this bump in the road stop progress on the project. In the video above you can see the helmet and its electronics working and sending data back to the Ground Operations Center.
That is going to wrap up my project summary coverage of project Trackable Safety Helmet for Miners. While this project was not as rich with knowledge as some of the others in the Safe and Sound Wearables Challenge, I chose to include it here because it illustrates what a complete project can be. All too often we see many projects that hit a major bump in the road, which causes progress to stall, if not die out completely. Despite several large hurdles, Mehmet continued to press forward with the project, and in the end, this perseverance led to him receiving an honorable mention from the judges. If you have not yet read through the whole project, I highly suggest doing so by visiting its blog page. Tune in later this week for another Design Challenge Project Summary here at Element14. Until then, Hack The World, and Make Awesome!