Progress On Device Build and Upcoming Validations

Over the period of Mar. 6 – Mar. 26, team 36 started with mounting the electrical components onto the pegboard. A figure was drawn to come up with the best placement of the components. A 9V battery that supplies the Arduino board with power is placed above the air blower. The Arduino board, the Relay Switch Module, and the breadboard were all permanently fixed onto the pegboard. The wires were regrouped and taped together to ensure that they did not get in the way of the nozzle movement. The plastic tubing was permanently fixed and sealed with the air blower to prevent leaking of air. The figure below shows the final build of our firefighting device, which has all the electrical components mounted on the pegboard: 

 

Figure 1: Final internal build set up

After all the components were mounted on the pegboard, the team then adjusted the code of the servo motors and the IR flame sensors. This was done by calibrating the device’s nozzle position by using fires at different locations and then adjusting the servo motor and IR flame sensor code. The team completed the calibration of the bottom two sensors and is left with the calibration of the upper two sensors.  

Team 36 has also received the Aluminum outer shell of the device from the machinist. After receiving the shell, the team realized that the outer edges of the shell still needed to be sealed. The team used an epoxy putty to seal the outer edges of the shell using clamps. 

The only non-technical challenge was miscommunication with the University of Houston machinist, which delayed the timetable for the aluminum heat resistant shield, but the team was able to finally get the part machined.  

During the past 2 weeks, there were a few technical challenges that the team had to overcome in order to wrap up the build of the prototype. One of the biggest concerns was the powder, which possessed uniquely high surface free energy that makes it easy to jam in whatever confined walls that it was in if the walls were too narrow in width or diameter. To allow a constant flow of powder, the team shortened the vertical height of the main tubing pathway right outside of the blower to create a slope for the powder to dislodge itself. Now, when the powder is displaced by the blower, the slope allows the rest of the powder to come down as needed.  

The aluminum shield was machined, but the team still had to figure out a way to seal the edges of the cover. The machinist recommended an epoxy and wrapping it with bungee cable or a clamp, so the team tried using 1 part metal epoxy and clamps to close the edges. Unfortunately, the epoxy sealant became undone, as can be seen in the figure below: 

 

Figure 2: Aluminum Shield

The top-right edge of our cover sprung apart after the curing period was over and the clamps were removed. The bottom left also came undone soon after the picture was taken, so it was decided to buy a stronger, 2-part epoxy for the next attempt.  

The last technical challenge is to optimize the device's range by tweaking the resistances of the sensors as well as the angles for each position in the servo motors. The team noticed some detection issues at the farthest range of the device at the end of the previous team meeting. The team plans to make the necessary adjustments in the next meeting, where a new aluminum epoxy will be applied to the device shield. 

Moving forward, the team plans to finalize the code for the device’s motor movement within the first portion of the week of March 29th . By mid-week, the team will conduct the validation tests for the device. This will include testing the device’s material endurance and functionality after being exposed to 2 hours of high heat and humidity from a boiling pot. The second validation test will demonstrate the device’s ability to target a fire within a 3-foot range, mimicking the area on a stovetop. The teams expect to see some challenges in this phase of the validation due to the fire sensor’s high sensitivity. The team needs to be able to refine the sensitivity threshold of the sensors so that the device is not triggered by outside sources of light, such as the sun. Once the validation data is collected, the team will conduct a project demonstration of the device to the client on April 7th demonstrating the device functions and the preliminary data collected. That same week on April 10th , the team will submit a technical report presentation that will go further in-depth of the validation data collected and what it means regarding the success of the device. The following week of April 12th the team will present its technical report to the client and commence the creation of the formal technical report.