Status Check for the Class and Project (As E-mailed by Evan) April 18, 2006
Posted by Tyler in Course, Fabrication.add a comment
So today [Monday] was a great day and here's a list of our accomplishments so far Things Done:
Our sensors works
The servo motor works and responds to frequency
The flashlight has been cut and modified w/holes for mounting
The stepper motor is mounted
The parts have all been beadblasted and look sexy, can you say Cal?
The axle has been cut and modified
Everything fits so far
The website looks great
and the other 102 groups are jealous and scrambling
however we're still not done.
We still need to:
Finish the code for the stepper motor and be able to run everything simultaneously
Wire in the electronics nicely
Design and fab the mounting for the power and dsp
Choose and obtain our power supply
Prepare slides and practice the oral presentation
Finish technical report (compile cads, bom, specs and calcs, catalogs and appendix)
Prepare the bike (clean it, blue and gold?, Cal somehow in the frame)
Design and make posterboard ( this should look pro and tie into proof of principle concept)
Complete website( WIP)
Turn in receipts
We are about 2/3 done, but fortunately this last 1/3 is mostly the fluff. Friday is a big day to get the project working and during the week would be a good opportunity to jump in on the fluff stuff. Keep working hard guys and i think we can win this thing, if not we can be damn proud of a very complete engineering project.
Mechanical Fabrication Almost Done! April 18, 2006
Posted by Tyler in Fabrication.add a comment
As of yesterday all of the parts to the mechanical design have been fabricated and assembled. All that remains is to lathe out an aluminum sleeve coupler for the stepper motor and gear. As soon as I get the photos from one of the group members, you can see the finished project (minus the wiring and coding of course – that's what we have left to do).
Status Update April 13, 2006
Posted by Tyler in Fabrication.add a comment
Things look to be coming along well. As of Tuesday this week we have almost all of our parts in. We may still be lacking some integrated circuits needed to control and power the stepper motor that came in the mail earlier this week. Jonathan is currently looking into what we may or may not need to control it. Evan and Erik are busily working in the machine shop to fabricate everything that is "finalized" design. Everything that does not anticipate any last minute changes falls into that category. I had the opportunity to see the finished, glass bead blasted support arms (the blue things in the CAD drawings on the right) and they look very well done. If nothing else, this project will look good. Matt has been out sick most of this week, but he will be getting better soon (he has to, his 22nd birthday is this Friday!). That's it for this most recent status update. Stay tuned for the programming (that's almost all that we have left!)
The State of Things April 4, 2006
Posted by Tyler in Design, Fabrication, Meetings.add a comment
As of today, we've managed to collect almost all of our parts. We are still shy on of our motor/servos needed for the focal adjustment, but things are in the works tonight. This particular piece of technology is proving difficult to come up with as nothing seems to meet the specifications and requirements needed. More on that later.
As of Sunday night, we've got a good idea of where this project is heading. Erik and Evan have both spent some time machining parts for the project and come up with some good preliminary results. Unfortunately, because of design modifications and new servo/motor changes, we may need to remachine these parts to get everything to fit. However, this has yet to be finalized. We did some additional machining today while in "lab" down in Etcheverry. John has been diligently working on the coding now that we have an idea of what we were doing with the servos. Several of us (mostly John) spent some time today trying to isolate what signal was needed for proper control. It looks like the DSP board doesn't work the way we need it to (something about the frequency output not being right and a few other problems, but John has some fixes in the works for that). Right now several of us are trying to come up with an alternative step motor to run the focal ring. The winch servos we were tossing around Sunday night just move too slow for what we need, so we're gonna have to go with a step motor to maintain that element of position control already in the servos, but the speed we need from a motor. We managed to bounce some ideas off of the GSIs during our "hardware presentation" during lab. We considered using an optical encoder, an optical interference sensor (something like that), and using one of the slower winch servos but with a bigger gear, all to maintain that speed and position control combination we so desperately need. By tomorrow we need to order what it is we're going to use since our time to put this all together is slowly winding down (we've only got four weeks left!). On top of all that, we still have to write a report and make the website (which is what you're reading – it's a work in progress!). It's gonna get fun with some really long nights!
No food, no drink, no explosives, no durians. April 4, 2006
Posted by hackinjat in Fabrication.add a comment
Just so everyone’s on the same page, I thought I’d explain how the servo’s work.
Essentially, the servo turns based on a pulse that it receives. The particular angle that it turns to depends on the pulse duration. The time between pulses doesn’t matter, as long as its in the range of 10 to 40 ms. For the pitch servo that we have right now, a 1.5 ms pulse rotates the servo to its “neutral” position that’s in the center of its turning limit. A 2 ms pulse moves the servo to one extreme.
The problem I was having to day was with the DSP. I was trying to use the built-in PWM function that we used in Lab 4 to generate pulses, but the problem is that the code can’t generate signals below around 1 khz. So, right now I’m writing my own code that will use one of the digital outputs on the board to generate pulses.
We’ll see how that goes. I’ll probably be in the lab tomorrow morning around 10 working on it before 102 “lecture.”
Backup Light March 19, 2006
Posted by Tyler in Fabrication.add a comment
Just as a precautionary measure, I ordered a backup flashlight today. If we screw up and destroy the first light through the fabrication process, then we’ll have this second one on hand. If we never need it, then I’ll just keep it and eat the cost. Hey, it’s a good light!
Bicycle Stand March 10, 2006
Posted by Tyler in Fabrication.add a comment
Rather than try to build a rear wheel supporting bicycle stand from scratch (as used as a training tool by many bike enthusiasts) we decided to try and acquire one via eBay or craigslist. Due to the constraints on our “cash flow,” we are limited in what we can afford. Many of these bike stands run upwards of several hundred dollars each. So, as of yesterday during the sensor testing session, we currently are bidding on one stand online and found another listing on craigslist that we will try to pursue. We will take advantage of any way to reduce fabrication time and materials acquisition, and right now this is the easiest approach to do that.
