After last week our group felt as though there wasn’t enough structure through our delegation and work loads. So to streamline our project and make our team more productive we decided to sit down at the start of every session and brainstorm ideas and delegate tasks for all of those ideas.Our group is made up of four people: Ronan, Nathan, Sean and myself. The tasks were given out to each member and were as follows:
My duties for the day was to build and get the color sensor (fig.1) working. I first began by drawing out the circuit to gain a better insight and overview. The factors that I knew straight away were that the maximum current allowed through the LED was 60mA, there was a 3.5 volt supply that would have a volt drop of 1.25 volts across the LED leaving 2.25V on the resistor connecting the LED to ground. I began to think that 60mA was far to bright and would also reflect the colour black. After using equations[ I=V/R ]and trial and error I found that 120Ω was the perfect resistance value. The next issue with the colour sensor was with determining the value of the resistor on the pull down switch. This was to be crucial for the output signal. After using equations [Vo=R1(Vin)R1/(R1+R2)] and trial and error a resistor of 10kΩ was used. With this now being applied, when the LED was reflecting on white the output signal was 3.3V and when it was hitting black the most voltage in the signal line was 0.3V. Meaning by using c code (fig. 2) when the signal voltage exceed 3V it knew it was on white.
I was also in charge of recording and analyzing the steps taken today with everyone’s work so their would be an ease of information when writing our blogs. The steps where usually: task – problems – solutions. At the beginning it was all done by addressing the obstacles ahead of us and turning them into tasks. I would then return in the middle of the class and record the issues they had with each of there tasks and finally at the end we had a debriefing to see how we each resolved our problems. With this way of recording our information I felt it gave everyone in the group an overview of what was going on in the project and our development.
Ronan was to work on the limit switch. His first issue was that he found a floating voltage on the pin of 0.8 volts. To resolve this Ronan put the floating voltage on the ground wire by switching around the floating voltage pin. Ronan was also in charge of coding the color sensor by distinguishing between black and white. The only issue Ronan had been that the LED on the sensor wasn’t working, but shortly afterward we found it was as simply to be the resistor on the Vcc was connected to the incorrect pin. Nathan was mostly part of our design team. He was researching for the design of the Robosimo and the material and came to the conclusion that perspects would be the lightest for speed and the most cost-effective. He was also designing our Facebook page where we could have a forum to share ideas when we’re not together. Before finishing the day he also neatened up the components on the bread board. Sean was to research future problems that lay ahead of our project and to print out the data sheets for the chips that we are working with. I felt this week we really made a lot of progress and I really do believe next week could be our week to have the first robot to the wall and back.
Figure.1: Colour sensor. Figure.2: C.Code