SeaWolf Updates
Monday, March 29, 2010 at 9:30PM Ah finally, reviving my blog. Things have been a bit dead, but now we're beginning to crank along. Hopefully I'll have time to update my other projects too, but we'll see.
So SeaWolf... It's that time of the year again when we can feel San Diego beginning to lurk around the corner and everyone starts ramping up their efforts. We currently have 3 major projects under development. We're testing vision pretty handily, all the time finding out that our PIDs and control systems weren't quite tuned or working as we had intended but luckily we're discovering this now and not at Transdec this year. We'll take it. A couple of minor things we're currently looking to rework vision wise
- Wide angle lense. This is hurting us.. vision keeps losing site of our target far before we get there leaving us in a dead reckoning state. If I remember correctly.. our test gate is a little smaller than the real gate, meaning this problem will only compound during competition.
- Better cameras. Our current cameras are webcams in fancy waterproof enclosures. While this is convenient in some aspects, in others it's a bit of an annoyance. A complete lack of control over auto-gain, auto-whitebalance and auto contrast can wreak havok on the image we're getting back. This boils down to the fact that off the shelf webcams weren't intended to deal with underwater lighting conditions, surprise surprise. We're looking for cameras currently that will allow for more fine grained control under linux, if you have any reccomendations, please shoot me an email (contact stuff in the side bar).
One of our members, Kevin Wolf is hard at work on a new power-board for SeaWolf. The current "power-squid-thing" is functional (loosely defined) but is easy to mis connect, looks like hell and generally needs to be cleaned up. In addition to tidying things up quite a bit Kevin is also preparing out switch to some form of modern battery technology. Currently we're in the process of investigating LiPoly as they seem to be the balance between energy density and explosiveness (li-ion being equated to placing incendiary grenades in our case with the pins pulled and hoping for the best) especially due to the high-current pull of our thrusters.
Finally, I've currently taken on the objective of ripping out a new motorboard for Seawolf. There's a few quirks in the current board that make it a bit difficult to deal with. The design objectives for this project are to reduce the USB cable count (we were going to try to cut down on the number of controllers... but this works for now). We're planning to achieve this through one of these guys, FT4232H by FTDI. This will allow us to communicate with 4 Arduinos. 3 will be used for motor control and a 4th will be broken out for use with sensors or anything else we decide we need (status lights etc). The current plan for the breakout (both analog and digital) is to provide:
signal1 voltage ground
signal2 voltage ground
This allows for 3 pin headers to be slapped in instead of having to run individual wires all over the place. A few fuses to protect our controllers and call it a day.
Reader Comments (2)
Hey, I'm Micah from the VT team. Dealing with webcams was a big issue for us too, but it turns out wide-angle lenses for them are pretty cheap (http://www.dealextreme.com/details.dx/sku.15237) and the automatic white-balancing can be turned off on most webcams (install xawtv and run the v4lctl util that comes with it). We are also switching to Li-Poly (from Li-Ion), so maybe ours won't have that "underwater grenade" aura, in the same way yours had the "brick in a box" feel. With the new batteries you can probably also switch to a much smaller hull too, right? Also, we've been thinking it would be kindof cool for our teams to get together before the competition and talk shop. What do you think?
Also, I like the FT4232H, and we've been considering using something similar, but we (un)fortunately haven't run out of serial ports on our computer yet!