On Sun, Dec 23, 2007 at 07:52:11AM -0800, Andrew Greenberg wrote: > Hi Mark, > > > The PARTS (http://www.portlandrobotics.org/) folks are kibitzing around > > doing a robo-Magellan http://www.robothon.org/robothon/robo-magellan.php > > kit. The design that folks are gravitating toward is to put together a > > platform that has a 6DOF IMU + 3 Axis Magnitometer + the typical robot > > related GPIO's and peripherals interfaced to a micro controller type of > > processor which is then interfaced via USB (full speed bulk) to a user > > provided USB host (laptop, Eee, OLPC, PC104, NSLU2...) > > > > I'm thinking we could join forces. > > This is, as always, a great idea and we'd love to do it. But usually, > our avionics system ends up begin a little to do weird for use with a > on-land robotics system. Flying robots with rocket engines and wheeled > robots just end up having very different electrical systems :)
Yeah, I know. > Our "generic" LPC2148 node was designed a year ago or so by a capstone > team. They did a great job, and the complete EAGLE schematics along with > documentation: > > http://psas.pdx.edu/CapstoneLV2bProjectReport/ > > Since then we've written some peripheral libraries for the LPC2148, but > unfortunately we haven't laid out the board yet. That's also on the > books for the next few months. > > I think there's a lot to be shared with sensor design: > > - Whatever GPS we end up using can certainly be shared, although it > might end up being too expensive for most robot use. > > - The 3D magnetometer sensor can certainly be re-used. ack. > > - The IMU sensor design might be good thing to share as well. But our > dynamic range and bandwidth is WAY bigger than what most robots will need. ack > > But, there are differences: > > - We have a very specially power distribution system. Instead of using > the standard USB 5V supply, we directly distribute a 14.4V Li Ion > (probably polymer) battery pack, and have switching supplies on each > board. For justification for that, see the Capstone report. The for the robot we would try to have the sensors / IMU be USB powered. > - We're very concerned about volume and weight, which means small, > packed, four layer boards. Since we have some free use of Screaming > Circuits' facilities, we'll probably end up using > 2 layer boards with > enthusiast-inappropriate chip packages like uBGAs and such. > > > What is the status of the LPC based IMU design and firmware? Where is > > it documented on the PSAS pages? > > The IMU in the planning stages right now. We'll probably pick the > sensors in the next two weeks (see http://psas.pdx.edu/SensorComparison/ > ), and begin the design shortly thereafter. All of the LPC nodes are > essentially vaporware right now, and we plan to fix that this winter :) Oh. That should be fun. > > If PARTS picks the LPC2148, then I think there's *lots* to be shared > back and forth. It probably won't be board design, but I bet we could > share sensor design and a lot of low-level firmware. > I was thinking this too, it would be nice if both used common micro processors. > I'm not sure what the PARTS timeline is like, but we hope to be done > with the generic node this spring and be working on sensor design > throughout the summer and have a complete package sometime later in > 2008. If PARTS is in more of a rush than that, then we may be borrowing > designs from you, rather than vice versa :) But hopefully this is > something we can collaborate on! > Well timelines are a function of who you ask, but some folks are thinking of building something by the end of this summer. I'm not sure I like talking time lines. --mgross
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