Mr Miyagi Moments - Week 2

This past week, our main lesson is that we need to pull in knowledge from all aspects of engineering. Furthermore, accepting that it is getting more complicated! I do not see this as a weakness or drawback, only an opportunity to accept there are always different solutions to problems.

https://www.youtube.com/watch?v=UR_eBVgX5iU

Our Monday meeting consisted of discussing and planning more meeting times within the week and taking to account our hectic schedule. We liaised with sensor city and other departments at the university regarding the use of their 3D printers. We considered different designs and materials for the robotic arm and brainstormed solutions for claw itself of the arm. With this in mind, we planned to simulate our plan on Tinkercad and to learn about the topic of gears and gear ratios.

The Tuesday and Thursday meetings built upon the outcome of the previous day, as the acrylic material was ordered, departments we had contacted replied and a more complex two button servo design was showcased to my absolute pleasure. Following a team exercise (explained in a later blog) we discussed the possibility of using an XBOX controller only once our arm was finished. As they use Bluetooth and we have a Bluetooth module for the servo at hand. This meeting mainly entailed beefing up our code for the servo.

Our Friday laboratory session led to a classic Mr Miyagi moment for me and my team in our journey. Like in the movie the Karate Kid, seemingly small insignificant fragments of knowledge we learnt on an off day in first year led to multiple break throughs. For example, one problem we had with the two-button control of a servo is that our 5-degree movement input led to a sporadic or at times unresponsive output from the motor of the servo itself. Once settling, the team bounced off each other and realised that in practice, real life circuits the voltage states can in exist in indeterminate region. The device will incoherently operate at logic level 0 or 1. Perhaps oscillating in-between the two. In short by adding a physical resister, the Arduino won’t be floating values and the logic level is certain. Our brilliant Miguel Li explains in detail in an attached document. We owe Miguel for a simplified solution to all of this with one line of code. The idea of adding umpteenth resistors gives me shivers whilst writing this blog.

To summarise what we achieved, we established the range of movement for the individual servos. As making it range from its minimum and maximum of 0 – 180 will burn it out. We finally have two button control for one servo and character input. IE turn only 10 degrees. This was established using the Pull up function. We have the complete designs for the robotic arm and have the designs and laser cuttings in queue. Then we finalised the what we will use for the claw itself. In this blog there is a link to the YouTube video on the two-button control. Then we summarised and planned our poster.

In total, our next meeting will discuss any problems we will have in creating our first design. Friday labs we deya.

Keith Marange

Project Manager