It's a tad less polished and maybe a bit more buggy than Eagle, but FreePCB ( here ) is FOSS Windows software. It works sufficiently well for me to be very productive. I've used it to make all of the circuitry for the Stanford Solar Car Project ( here ).
It's much easier to use than Eagle and does make you go through as much bigma to get a board made.
Cray has since moved on from the stuff for their middle range computers, but their iconic old big cylinder super computers were completely chock full of the stuff. I found something from 2002 that indicates they still use it in their highest end equipment:
http://www.cray.com/downloads/crayx1_dhbrown.pdf
It is electrically insulating and is commonly used for cooling electronics (think Cray supercomputers).
Part of the problem with conformal coat is that it makes it hard to service the electronics after it is cured. It also may or may not be uniformly distributed and thus may not pass muster in a tank of conductive liquid.
There are conductive epoxies like Stycast, but they're not particularly good conductors. The only reason to do immersion cooling is for good thermal contact to all components. A thick epoxy layer between your components and your liquid will quickly destroy that advantage.
Also, if you have connectors to the circuit board (like PCI connectors), then you cannot fill the pins. Last time I checked, most PCI connectors are just slots and have no bottom fill. Water will certainly get in under the coating through the slot.
That's absolutely the truth. Solar car racing is way cooler than the American public gives it credit for. It's a real shame that there's not more publicity and more opportunity for some of us slightly less well endowed (in terms of manpower) teams to interface with industry and really do great things.
I'm glad to hear that so much testing goes in to making sure the UM cars are safe. Certainly at first glance a lot of things seem bad. The driver position still sticks out at me as something that shouldn't be repeated. Also, analysis of composites is hard and usually the answer is to just over build them. That's certainly what we do. The only analysis we do is to find the cross sectional area of the fiber in the direction of the load and treat it as a metal surface with the tensile strength of carbon fiber.
I've heard some fleeting reports that MN has had battery problems and may have to duck out. Do you happen to have any more details on this? I think MN is a great case study in solar car sportsmanship. I went to the NASC scrutineering and qualifying mostly just to chat it up with teams, learn what I could, and see what the race was about. While there they volunteered parts and help to other teams. Depending on who you got with UM, sometimes you'd get great conversation and plenty of advice and help. Sometimes you'd get someone who really just wanted you to go away. My impression is that the team has been getting better with time.
I've been trying to keep pretty open about what it is we've been up to. I post complete PCB drawings of our electricals, pictures of our batteries, CADs of our mechanicals, etc. My thought has been it's better to improve the state of the art than to try to be secretive about things. I'm even planning on open sourcing the software and hardware to my homemade MPPTs as soon as it's ready for showtime.
I made no complaints about the concentrator, nor about Michigan's huge budget. The UM team works hard to secure the funding that they do, and I can respect that.
Go read the solar vehicle challenge list. I even posted an RFC for rules changes that would specifically allow Michigan's concentrator. It's a design feature I admire and I think it's wrong that you were not allowed to use it to its full capacity in NASC.
You've missed the point of my post entirely. You have interpreted my post from a competitive advantage perspective, not a sportsman's perspective. When I say risky, I don't mean from a potential performance benefit versus cost and risk calculation. I mean risky as in the driver's safety is compromised in order to shave a few pounds or make the aero profile a tiny bit better.
Michigan is a great team that does great things, but sometimes the focus on winning blurs out the purpose of the event and reorders the priority list in a dangerous way. Nuna is much the same way. Their car is a rickety death trap that I would never drive.
Sorry about the flame- I am an ex-UM member and am still a little bitter.
I can see that.
Solar car is about building experience and becoming better at what you do. You can't fault a guy for learning from his mistakes and doing things better the second time around. What is an education for?
UM has lost focus of the spirit of the event. This is a race, but it's not a race to a finish line. It's a race to learn as much as you can in the limited time you have as an undergraduate in a club activity.
Michigan wants so badly to win that they realize needlessly risky designs to pursue fleetingly small perceived advantages. Gaming the race framework and then blaming the outcome of borderline engineering on others is bad form and is representative of the poor sportsmanship that has given the team such a bad reputation in the solar car racing community.
Now, that is not to say that everyone on the UM team is a bad person. There are many fine engineers and upstanding people on the UM team, but their good work, high spirits, passion for the sport, and good conduct are easily eclipsed by the few members of the UM team that don't hold those values as highly.
I would like to point out that the race officials concluded that Stanford had no culpability in Michigan's accident. Observers from both teams provided the details to reach that final decision.
Maybe next time UM shouldn't use brakes designed for a bicycle on a solar car.
Wow! I saw those while I was out at the race and I swore I would track them down on the web to try and use on our team's solar car. I'm totally bowled over that I should chance over them on slashdot of all places.
You wouldn't happen to want to donate a few of those to the Stanford team too, would you?
Slashdot Mirror
It's a tad less polished and maybe a bit more buggy than Eagle, but FreePCB ( here ) is FOSS Windows software. It works sufficiently well for me to be very productive. I've used it to make all of the circuitry for the Stanford Solar Car Project ( here ).
It's much easier to use than Eagle and does make you go through as much bigma to get a board made.
Cray has since moved on from the stuff for their middle range computers, but their iconic old big cylinder super computers were completely chock full of the stuff. I found something from 2002 that indicates they still use it in their highest end equipment: http://www.cray.com/downloads/crayx1_dhbrown.pdf
It's also used at SLAC for cooling electronics: http://www-conf.slac.stanford.edu/bfactory-decom/Talks/Wisniewski2.pdf
Looks like it's also used to cool industrial equipment that can't be exposed to reactive chemicals, like wafer ion implantation systems: http://multimedia.mmm.com/mws/mediawebserver.dyn?6666660Zjcf6lVs6EVs666YNqCOrrrrQ-
It is electrically insulating and is commonly used for cooling electronics (think Cray supercomputers).
Part of the problem with conformal coat is that it makes it hard to service the electronics after it is cured. It also may or may not be uniformly distributed and thus may not pass muster in a tank of conductive liquid.
There are conductive epoxies like Stycast, but they're not particularly good conductors. The only reason to do immersion cooling is for good thermal contact to all components. A thick epoxy layer between your components and your liquid will quickly destroy that advantage.
Also, if you have connectors to the circuit board (like PCI connectors), then you cannot fill the pins. Last time I checked, most PCI connectors are just slots and have no bottom fill. Water will certainly get in under the coating through the slot.
That's absolutely the truth. Solar car racing is way cooler than the American public gives it credit for. It's a real shame that there's not more publicity and more opportunity for some of us slightly less well endowed (in terms of manpower) teams to interface with industry and really do great things.
I'm glad to hear that so much testing goes in to making sure the UM cars are safe. Certainly at first glance a lot of things seem bad. The driver position still sticks out at me as something that shouldn't be repeated. Also, analysis of composites is hard and usually the answer is to just over build them. That's certainly what we do. The only analysis we do is to find the cross sectional area of the fiber in the direction of the load and treat it as a metal surface with the tensile strength of carbon fiber.
I've heard some fleeting reports that MN has had battery problems and may have to duck out. Do you happen to have any more details on this? I think MN is a great case study in solar car sportsmanship. I went to the NASC scrutineering and qualifying mostly just to chat it up with teams, learn what I could, and see what the race was about. While there they volunteered parts and help to other teams. Depending on who you got with UM, sometimes you'd get great conversation and plenty of advice and help. Sometimes you'd get someone who really just wanted you to go away. My impression is that the team has been getting better with time.
I've been trying to keep pretty open about what it is we've been up to. I post complete PCB drawings of our electricals, pictures of our batteries, CADs of our mechanicals, etc. My thought has been it's better to improve the state of the art than to try to be secretive about things. I'm even planning on open sourcing the software and hardware to my homemade MPPTs as soon as it's ready for showtime.
I made no complaints about the concentrator, nor about Michigan's huge budget. The UM team works hard to secure the funding that they do, and I can respect that.
Go read the solar vehicle challenge list. I even posted an RFC for rules changes that would specifically allow Michigan's concentrator. It's a design feature I admire and I think it's wrong that you were not allowed to use it to its full capacity in NASC.
You've missed the point of my post entirely. You have interpreted my post from a competitive advantage perspective, not a sportsman's perspective. When I say risky, I don't mean from a potential performance benefit versus cost and risk calculation. I mean risky as in the driver's safety is compromised in order to shave a few pounds or make the aero profile a tiny bit better.
Michigan is a great team that does great things, but sometimes the focus on winning blurs out the purpose of the event and reorders the priority list in a dangerous way. Nuna is much the same way. Their car is a rickety death trap that I would never drive.
Sorry about the flame- I am an ex-UM member and am still a little bitter.
I can see that.
Solar car is about building experience and becoming better at what you do. You can't fault a guy for learning from his mistakes and doing things better the second time around. What is an education for?
UM has lost focus of the spirit of the event. This is a race, but it's not a race to a finish line. It's a race to learn as much as you can in the limited time you have as an undergraduate in a club activity.
Michigan wants so badly to win that they realize needlessly risky designs to pursue fleetingly small perceived advantages. Gaming the race framework and then blaming the outcome of borderline engineering on others is bad form and is representative of the poor sportsmanship that has given the team such a bad reputation in the solar car racing community.
Now, that is not to say that everyone on the UM team is a bad person. There are many fine engineers and upstanding people on the UM team, but their good work, high spirits, passion for the sport, and good conduct are easily eclipsed by the few members of the UM team that don't hold those values as highly.
I would like to point out that the race officials concluded that Stanford had no culpability in Michigan's accident. Observers from both teams provided the details to reach that final decision.
Maybe next time UM shouldn't use brakes designed for a bicycle on a solar car.
Wow! I saw those while I was out at the race and I swore I would track them down on the web to try and use on our team's solar car. I'm totally bowled over that I should chance over them on slashdot of all places. You wouldn't happen to want to donate a few of those to the Stanford team too, would you?
Michigan won the 2005 American Solar Challenge race by about ten minutes over Minnesota.
My team won the 2005 American Solar Challenge for the stock class, edging out Berkeley by 26 minutes.