This will be the last blog post for the Alfred project. To begin, here's a little history:
The project idea was conceived god knows how long ago (3 years?) and started first semester my freshman year, Fall 2012. I had originally joined so I could learn Arduino and robotics wasn't totally foreign to me since I did FIRST all throughout high school. After a year of casually participating I decided to pick it up over the summer since I wasn't doing anything else. After this, I got roped into being the project lead since everyone else quit and I didn't want to be the one to leave the project to die.
What went wrong:
A lot. For the first semester (of my tyranny), we had no money due to administrative issues. There was good deal that needed to be fixed that needed new parts so most of our meetings were us sitting in EHC doing absolutely nothing. Once we did get funding from the school, there wasn't nearly enough time to finish for the Accepted Students Day deadline.
And now this is the end. Most of us have lost interest in the project and have found other things going on. The remains of Alfred will stay in the EHC closet for the foreseeable future until another ambitious freshman wants to take on the project.
I was told by some of the leaders to elaborate a little more so I'll give it another shot.
When I was handed the project, Alfred was kind of in a wreck to no fault of my predecessors. The previous year involved quite a bit of rushing as well. This is some of the stuff I did in the past two semester.
To start, the motors were directly mounted to the top of the base plate with a wheel keyed onto the end of the motor shaft. Because of this, the weight of Alfred would apply a torque onto the motor shaft and occasionally lock up the motors which I would have to rebuild every so often. So the first plan of action was to redesign the entire drive train system. Hopefully into something that actually had bearings and gears and stuff. This final design could be seen on our last blog post. The fatal flaw for this design (which was finished earlier this semester) was the motor selection. These motors where lent to me by a friend of mine who had no other use for them. Little did I know these were actually spindle motors, like for CNC machines. That basically means they are the kind of motors that are meant to be spinning very fast before applying a load to it. In the application they were used for in this case, there was already a load applied to it (the resulting torque from the weight of Alfred) before it started spinning. Needless to say, the motors weren't very happy with us and usually needed a push before starting and even then they didn't cooperate.
As far as the drink dispensing system goes, that was also in need of renovating. The system was set up so that there were four 2-liter bottles that lined the bottom of the front panel of Alfred. In each bottle was a hole drilled at the bottom with a hose feeding into it and a hose coming out of the mouth. The idea was to have tank of compressed air shoot air through the bottom of each bottle and the result would be liquid shooting out the top which then gets fed to a contraption that puts said drink into your cup. Don't get me wrong, it worked. The only probably was how were you supposed to refill the drinks especially when everything was sealed with some magical FDA approved silicone caulking? The new design was to have the two hoses going into a modified bottle cap, leaving the bottles themselves untouched. The idea is when air gets shot into the bottle, drink would also shoot out the top. It worked when we tested it but we didn't have time to add it to Alfred. Don't ask me why we didn't just flip the bottles upside down and call it a day. I still don't know the answer to that.
Since we weren't going to have time to finish the drink dispensing system for Accepted Students Day, the night before we went to Walmart and bought an RC car and a Nerf gun. We hacked apart the RC car and used the remote to control Alfred since we were most likely going to run into problems with Bluetooth interference with crowds of people and RC cars are kind of made for that. The Nerf gun was a substitute to the drink system so Alfred wasn't just a black box with a limp. We made it controlled by one of the buttons on the RC remote in addition to making an Android app for everything that worked over Bluetooth. On the tablet, we also made it box peoples' faces in red and say something along the lines of "Enemy Detected" on top. While we were at our table at Accepted Students Day with EHC, we also implemented the RPI-RFID reader (another EHC project) by having it unload the entire magazine onto anyone who swipes their student ID. Everything was exceptionally silly but actually a lot of fun.
And that's the end.
Saturday, March 29, 2014
Alfred the Butler Bot
What we are up to.
Over the last semester we have begun finishing up our design and are building the robot. We have a drive train now. We are using two motors for independent control of the robot. Two solid states relays are used for powering the motors from the battery. We were originally working on making the robot line following but now we are going to make it move randomly like a Roomba. Drink dispensing uses a Galaxy Tab with facial recognition in it to stop and serve people drinks.Things are under a time crunch and we are rushing to finish everything by Accepted Students Day on Saturday.