This second blog in the Hazardous Environmental Factors project publishes a bit more of the project plan and the proposed instrumentation system.
The the issues addressed will be expanded upon in future blogs.
The Project Plan
Research - The first step in becoming safe and sound is to know the dangers and risks.
- The problems addressed by the project will be researched
- The instrumentation that is needed to quantify the problems will be researched and selected
- The challenge kit of parts will be researched with respect to using them in the project
System Design - Once the issues and objectives are identified and understood we need to design a solution
- Block diagram
- PCB Design
- Wearable Chassis design
- Software Design
- Power supply design
Material Procurement - As soon as components and materials are identified they must be procured
- Material needed for the project will be sourced and procured
System Build - System build can start as soon as material starts to arrive, or 3D printed components are complete
- Electronics build, Mechanical Build, Software programming, 3D printing
Developmental Testing - Subsystems should be tested before full system test
- System electrical testing, System software testing, System mechanical testing
System Application Tests - After the full system is working, it can be used to take data and fulfil its purpose
- The system will be used to audit my environment
Documentation & Conclusions - Project documentation needs to be continuous in the form of blogs
- Each of the project plan tasks will include a related blog
The instrumentation that I am proposing to use to monitor the invisible entities outlined above takes up a considerable amount of physical space, as does the supplied kit of modules to be used in the challenge. It could easily fill up a backpack, but in order to better meet the wearable requirement, I will package all the instrumentation in a forearm-mounted modules. Although it will be too large for everyday wearing, I want to at least make it wearable, useful, ergonomic and aesthetically professional looking.
The plan is to have 4 displays, a touch pad, and UV sensor lined up along the top of the forearm, one of the displays will be the Sharp graphics LCD that is part of the challenge kit.
Display 1 - a,b,g, x radiation
Display 2 - EMF (ELF magnetic field, electric field, & RF)
Display 3 - microwave & RF field strength
Display 4 - UV & air quality (O2,CO2,CO,VOC)
Along the inside of the forearm will be the computer module and Wi-Fi Booster (parts of the challenge kit).
Along the outside of the forearm will be a suite of environmental sensors.
On the underside of the forearm will be the battery and power supplies.
At least 2 of the instruments will need mechanisms to fold away when not in use. Each folding mechanism requires five 3D printed parts.
At least 10 of the modules will require 3D printed cases to mount on the sleeve, where each case may need 2 or more 3D parts.
Aside from 3D parts, the mechanics of the system will need some soft goods, pads and straps to attach comfortably to a forearm.
Electrically the air quality sensor suite will require a custom (Booster Pack) PCB to turn them into a module.
Firmware will be needed to read and display sensor data, and I would like to publish the data on an MQTT broker since the kit includes a Wi-Fi module. Hopefully I can use a Raspberry Pi as the MQTT broker.
System Block Diagram
Summary & Notes
This wearable environmental factors instrumentation system is a fairly ambitious project with many challenges, but I find the subject matter and chance to learn and stretch my capabilities very motivating. Although there will be a lot of work associated with sourcing and procuring instrumentation, learning device characteristics, designing and building hardware and programming firmware, most of it is the type of engineering I am familiar with. The main risks for me are learning and trusting other people's software, such as MQTT broker software, but it is a good opportunity to explore this interesting technology.
There is a significant problem in finding low cost sensors that will interface to a computer while providing reasonable data, so part of this project is a fairly comprehensive search for suitable instrumentation. This has already been researched enough to build the above block diagram, however there are a lot of peripherals in the plan and I have not done enough detailed design yet to know if there are enough pins on the MCU to interface with all of these devices. There are 4 Booster packs from the supplied kit in my block diagram but I'm not sure even these can all work together – they certainly don't look stackable.
I still expect the design challenge modules kit should make a fine wearable platform with an MCU a Wi-Fi link and a LCD forming the core platform The core platform can always be extended as new peripherals become available or feasible
This is an exciting design challenge that fits well with my interests in wearable technology and IoT. I have already benefited by doing fairly extensive research and conceptual design for this proposal.
I have started designing a custom sensor Booster Pack and some of the 3D printed cases but they are far from ready to publish. I have also started ordering some components - as they get chosen. The next blog will likely discuss some of the environmental hazards that will be monitored.
All links to blogs related to this project can be found in the first blog here: