Comments for Doswa http://doswa.com/blog Programming, physics, mathematics Fri, 11 Jun 2010 03:14:37 +0000 hourly 1 http://wordpress.org/?v=3.0.1 Comment on JavaScript physics by David http://doswa.com/blog/2009/01/16/javascript-physics/comment-page-1/#comment-1579 David Fri, 11 Jun 2010 03:14:37 +0000 http://doswa.com/?p=68#comment-1579 Collisions would actually be quite easy to implement for this, since it uses Verlet integration. Apply a basic circle-circle collision test, then just modify the particles' positions so they're no longer overlapping. Keep in mind conservation of momentum when modifying the positions. Verlet integration works by implicitly keeping track of the velocity by holding on to the previous position (i.e. $$v = x - x*$$, where $$x*$$ is the previous position), so momentum would be conserved like $$\Delta (m_1 (x_1 - x_1*)) + \Delta (m_2 (x_2 - x_2*)) = 0$$. Collisions would actually be quite easy to implement for this, since it uses Verlet integration. Apply a basic circle-circle collision test, then just modify the particles’ positions so they’re no longer overlapping.

Keep in mind conservation of momentum when modifying the positions. Verlet integration works by implicitly keeping track of the velocity by holding on to the previous position (i.e. v = x - x*, where x* is the previous position), so momentum would be conserved like \Delta (m_1 (x_1 - x_1*)) + \Delta (m_2 (x_2 - x_2*)) = 0.

]]> Comment on JavaScript physics by Ben http://doswa.com/blog/2009/01/16/javascript-physics/comment-page-1/#comment-1578 Ben Fri, 11 Jun 2010 01:39:26 +0000 http://doswa.com/?p=68#comment-1578 Great work. Its missing self-collision though. I'm just mentioning this because it looks a bit weird without it. Great work. Its missing self-collision though. I’m just mentioning this because it looks a bit weird without it.

]]> Comment on SparkFun’s FTDI Basic Breakout as an AVR programmer by antoine http://doswa.com/blog/2009/12/20/sparkfuns-ftdi-basic-breakout-as-an-avr-programmer/comment-page-1/#comment-1551 antoine Thu, 03 Jun 2010 01:40:03 +0000 http://doswa.com/blog/?p=308#comment-1551 Thanks a lot for the tutorial. After a bit of tinkering, I got it to work. My problem was that I was programming an ATmega328p on a breadboard so it was (until I figured it out) missing a pull-up resistor on the RESET line. Thanks a lot for the tutorial. After a bit of tinkering, I got it to work. My problem was that I was programming an ATmega328p on a breadboard so it was (until I figured it out) missing a pull-up resistor on the RESET line.

]]> Comment on DIY aux input on Alpine car stereo (M-BUS) by David http://doswa.com/blog/2010/01/01/diy-aux-input-on-alpine-car-stereo-m-bus/comment-page-1/#comment-1456 David Tue, 18 May 2010 21:18:03 +0000 http://doswa.com/blog/?p=324#comment-1456 The M-BUS protocol does not require a trigger signal (thought it can accept one—details at http://web.archive.org/web/20050509160913/http://joerg.hohensohn.bei.t-online.de/mbus/). Provided the radio is set to the correct mode (aux), it just amplifies whatever is sent into left/right signal pins. As for setting it to the correct mode, check your radio's manual. If you don't have the original, look up the model number online and I'm sure you'll be able to find it. The M-BUS protocol does not require a trigger signal (thought it can accept one—details at http://web.archive.org/web/20050509160913/http://joerg.hohensohn.bei.t-online.de/mbus/). Provided the radio is set to the correct mode (aux), it just amplifies whatever is sent into left/right signal pins. As for setting it to the correct mode, check your radio’s manual. If you don’t have the original, look up the model number online and I’m sure you’ll be able to find it.

]]> Comment on DIY aux input on Alpine car stereo (M-BUS) by V http://doswa.com/blog/2010/01/01/diy-aux-input-on-alpine-car-stereo-m-bus/comment-page-1/#comment-1455 V Tue, 18 May 2010 19:55:40 +0000 http://doswa.com/blog/?p=324#comment-1455 I have the same plug in my old Mercedes branded Alpine radio. But I don't have a "Setup" menu. I believe there is a remote trigger signal that needs to be sent to the radio to switch it into the CD Player mode. Do you know which line needs to be triggered? I found a reference to it here http://www.rockbox.org/mail/archive/rockbox-archive-2003-11/0476.shtml but none of the links work. Do I need to add 12v to the bus pin? I have the same plug in my old Mercedes branded Alpine radio. But I don’t have a “Setup” menu. I believe there is a remote trigger signal that needs to be sent to the radio to switch it into the CD Player mode.

Do you know which line needs to be triggered? I found a reference to it here http://www.rockbox.org/mail/archive/rockbox-archive-2003-11/0476.shtml but none of the links work. Do I need to add 12v to the bus pin?

]]> Comment on AVRDUDE 5.8 with FTDI bitbang patch on Linux by David http://doswa.com/blog/2009/12/20/avrdude-58-with-ftdi-bitbang-patch-on-linux/comment-page-1/#comment-1357 David Fri, 07 May 2010 02:18:34 +0000 http://doswa.com/blog/?p=292#comment-1357 @lundnul I talked to my friend and he said he's using the serjtag variant of the avrdude package from MacPorts. http://www.macports.org/ports.php?by=variant&substr=serjtag @lundnul

I talked to my friend and he said he’s using the serjtag variant of the avrdude package from MacPorts.

http://www.macports.org/ports.php?by=variant&substr=serjtag

]]> Comment on AVRDUDE 5.8 with FTDI bitbang patch on Linux by Brad http://doswa.com/blog/2009/12/20/avrdude-58-with-ftdi-bitbang-patch-on-linux/comment-page-1/#comment-1350 Brad Thu, 06 May 2010 05:01:25 +0000 http://doswa.com/blog/?p=292#comment-1350 Awesome! All I had laying around was a few FT232R chips and I needed an AVR ISP for an ATmega8L and this worked just great. Thank you. Awesome! All I had laying around was a few FT232R chips and I needed an AVR ISP for an ATmega8L and this worked just great. Thank you.

]]> Comment on AVRDUDE 5.8 with FTDI bitbang patch on Linux by David http://doswa.com/blog/2009/12/20/avrdude-58-with-ftdi-bitbang-patch-on-linux/comment-page-1/#comment-1347 David Wed, 05 May 2010 10:39:46 +0000 http://doswa.com/blog/?p=292#comment-1347 @lundnul I believe a friend of mine got it working under Mac OS X. I'll talk to him and see if he can help you out. @lundnul

I believe a friend of mine got it working under Mac OS X. I’ll talk to him and see if he can help you out.

]]> Comment on AVRDUDE 5.8 with FTDI bitbang patch on Linux by lundnul http://doswa.com/blog/2009/12/20/avrdude-58-with-ftdi-bitbang-patch-on-linux/comment-page-1/#comment-1343 lundnul Wed, 05 May 2010 05:27:02 +0000 http://doswa.com/blog/?p=292#comment-1343 Anyone who got this working under MacOS? I am stuck with the configure script, stating that my gcc cannot produce executables (though I'm not sure that's the actual error) Anyone who got this working under MacOS? I am stuck with the configure script, stating that my gcc cannot produce executables (though I’m not sure that’s the actual error)

]]> Comment on SparkFun’s FTDI Basic Breakout as an AVR programmer by Kaoss Guitar - Day 1 | Doswa http://doswa.com/blog/2009/12/20/sparkfuns-ftdi-basic-breakout-as-an-avr-programmer/comment-page-1/#comment-1237 Kaoss Guitar - Day 1 | Doswa Sun, 18 Apr 2010 10:32:52 +0000 http://doswa.com/blog/?p=308#comment-1237 [...] problem I ran into using my FTDI programmer was the clock rate. A fresh ATmega328P comes running at 1 MHz, significantly lower than the default [...] [...] problem I ran into using my FTDI programmer was the clock rate. A fresh ATmega328P comes running at 1 MHz, significantly lower than the default [...]

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