 | | Re: Ultrasonic Sensor
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(...) Yep - I thought so...for things like cameras where these things are in common use, the need is only to know the range to the nearest object. I don't even know if the other things (multiple object detection and size/reflectance estimation) are (...) (24 years ago, 6-Feb-02, to lugnet.robotics)
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| | Re: Ultrasonic Sensor
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(...) let (...) Thanks for that Steve. My circuit will be based on the latter of the two possibilities. It is based on a design by RA Penfold from Electronics and Beyond (Sept.2001) so I'm basically doing construction by numbers! However, the thesis (...) (24 years ago, 6-Feb-02, to lugnet.robotics)
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| | Help with Homebrew sensor
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Hi all, my name is Francis (from Spain). I've read Extreme MindStorms and I decided to put my hands on and build some new sensors. I began with the optointerrupter, but have a little trouble. When I connect the sensor to the RCX I can't get a stable (...) (24 years ago, 6-Feb-02, to lugnet.robotics)
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| | Re: Ultrasonic Sensor
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(...) I guess the first question I'd ask is "What interface does the sensor present to the RCX?" I imagine there are two possibilities: It could be a raw interface that let you send an acoustic "PING" on command and read a voltage back telling you (...) (24 years ago, 6-Feb-02, to lugnet.robotics)
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| | Real time operating system resources
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Now that my interest has been piqued by the multiplexer problem (and sensing problem in general), what would some of you hardened embedded/real-time system veterans recommend for reading on the subject. Two books that I've found at Amazon.com are (...) (24 years ago, 6-Feb-02, to lugnet.robotics.rcx.legos)
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| | Ultrasonic Sensor
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Hello all. This topic might be a bit old hat for some of you, but as a relative newbie to the world of Mindstorms, I'm posting in the appeal for any information on Ultrasonic Sensors. The brief of my honours project was to design and build one such (...) (24 years ago, 6-Feb-02, to lugnet.robotics)
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| | Re: Power to RCX
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Success! It works now, and gives 9.2 volts according to the RIS software. You were right, I did have it backwards. Thanks. (...) (24 years ago, 5-Feb-02, to lugnet.robotics.rcx)
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| | Re: multiplexor and legOS
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(...) I'm just checking this thing out. You can look at: (URL) more information. Unfortunately, I got the .ps description file but not the source code patch file. A mail asking for it is on it's way ;) Mike (24 years ago, 5-Feb-02, to lugnet.robotics.rcx.legos)
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| | Re: multiplexor and legOS
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(...) Actually, something like this has been documented and done by Pedersen, Christensen, Rasmussen ("Prioritized Interrupts in LegOS"). They actually document the problem of sensor misses related to task management, significantly reducing the (...) (24 years ago, 5-Feb-02, to lugnet.robotics.rcx.legos)
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| | Re: Running Vision Command on XP
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(...) I now have Studios up and running within XP. I had to download a new driver from the Logitech site for the camera and then it was just a case of setting the compatibility option for Lego Studios so that it thinks it is still running in Win (...) (24 years ago, 5-Feb-02, to lugnet.robotics.vc)
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| | Re: multiplexor and legOS
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(...) Most people's legOS kernels will be compiled so msleep uses wait_event. I haven't looked at the code, but my understanding of how wait_event works is that whenever that thread becomes eligible to execute, your even function is called. (...) (24 years ago, 5-Feb-02, to lugnet.robotics.rcx.legos)
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| | Re: multiplexor and legOS
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Try the following code fragments. [Change to fixed spacing font so that it reads easily.] You should be able to find what you need. "Mark Falco" <> wrote in message news:Gr1MBL.Dop@lugnet.com... (...) <<..snip..>> (...) These are code fragment for (...) (24 years ago, 5-Feb-02, to lugnet.robotics.rcx.legos)
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| | Re: multiplexor and legOS
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Ok, my last port didn't make much sense let me try that again. for an active sensor ds_handler will periodically power the sensor off to read the value. The standard firmware does this to but at a different interval. I'm wondering if this is part of (...) (24 years ago, 5-Feb-02, to lugnet.robotics.rcx.legos)
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| | Re: multiplexor and legOS
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Since I'm now fairly sure that i've got the timing taken care of I'm wondering if the power cycling that ds_handler does is somehow causing the problem? I thought I might take control of this stuff in my test code. I assume if I set the sensor for (...) (24 years ago, 5-Feb-02, to lugnet.robotics.rcx.legos)
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| | Re: multiplexor and legOS
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(...) It looks like the semaphore task_sm should prevent another task from being scheduled if I hold it for the length of the train. I've now tried this as well as incresing the timeslice to 100ms. It looks better but still is not consistent. Since (...) (24 years ago, 5-Feb-02, to lugnet.robotics.rcx.legos)
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| | Re: Motorized landing gear question
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(...) (These are identical to Mindstorms motors - right? Certainly the motors *I* picked up from Znaps sets are indistinguishable from Mindstorms motors ...I don't think they ever shipped a different one with Znaps.) (...) Well, the worm gear should (...) (24 years ago, 5-Feb-02, to lugnet.robotics)
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| | Re: Motorized landing gear question
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(...) I'd suggest it's not necessary for the landing gear to lift the craft - just to hold it up. If it's only operated while there's no weight on the craft, it becomes much easier, you only need some kind of locking mechanism so the motor isn't (...) (24 years ago, 5-Feb-02, to lugnet.technic, lugnet.robotics, lugnet.space, lugnet.znap)
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| | Re: multiplexor and legOS
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(...) Not bad. But as you say, still vulnerable to the task switching problem. (...) Instead of resorting to that, maybe there is a way to freeze task switching during critical operations. When I owned and programmed the AmigaOS (don't laugh :), (...) (24 years ago, 5-Feb-02, to lugnet.robotics.rcx.legos)
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| | Motorized landing gear question
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I've been pondering using one of the Znap motors to power a landing gear mechanism strong enough to at least hold, if not lift a decent sized space craft (including the motor and battery box- if possible) Any ideas? I was thinking worm gear and some (...) (24 years ago, 5-Feb-02, to lugnet.technic, lugnet.robotics, lugnet.space, lugnet.znap)
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| | Re: multiplexor and legOS
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#include <sys/time.h> void systime_set_timeslice (unsigned char slice); include/sys/time.h:43-45: #ifdef CONF_TM #define TM_DEFAULT_SLICE 20 file://!< default multitasking timeslice #endif hope that helps, Albert "Michael J Ash" (...) (24 years ago, 4-Feb-02, to lugnet.robotics.rcx.legos)
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| | Re: multiplexor and legOS
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(...) I agree about the cause for the msleep granularity, I'd seen the same stuff in tm and assumed that would cause the problem. Sorry my last note was a little unclear, I tried msleep and delay but am now using my own function which seems to (...) (24 years ago, 4-Feb-02, to lugnet.robotics.rcx.legos)
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| | Re: Secondary Education Robotics
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(...) Hi, have a look at (URL) is more than two years of work with secundary students. Claude Baumann (24 years ago, 4-Feb-02, to lugnet.robotics.edu)
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| | Re: multiplexor and legOS
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(...) I don't know about this 20ms granularity and how delay() is going to be any better. Here's the code for each function: //! delay execution allowing other tasks to run. /*! \param msec sleep duration in milliseconds \return number of (...) (24 years ago, 4-Feb-02, to lugnet.robotics.rcx.legos)
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| | Secondary Education Robotics
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Hi, I'm part of a university group trying to compile a list of ways that robotics are being used in high school classrooms. If you are a person involved with the use of robotics in high school science, math, and technology courses, and are (...) (24 years ago, 4-Feb-02, to lugnet.robotics.edu)
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| | Re: multiplexor and legOS
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(...) Thanks, I'd suspected that msleep might not be very accurate but never considered that it's true granularity could be so large. I did a quick test with my current configuration and when I asked msleep to sleep for 12ms it slept for 20. This (...) (24 years ago, 4-Feb-02, to lugnet.robotics.rcx.legos)
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| | Re: Question?
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(...) No, there's no bridge in the RCX, just a pull-up to 5V (10kOhm IIRC). If you look at the schematics (say at (URL) see that there is another bridge rectifier in the sensor between ground and the raw sensor output. The ground half of the bridge (...) (24 years ago, 4-Feb-02, to lugnet.robotics)
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| | Re: true tcp/ip on the RCX
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(...) The C64 server survived the "Slashdot attack" without problems, even though it served tenths of thousands of pages over a period of only a few hours. Since it is configured to allow only 10 simultaneous connections, it could more or less serve (...) (24 years ago, 4-Feb-02, to lugnet.robotics.rcx.legos)
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| | Re: JAVA for 9751 Lego interface - SOS
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(...) It seems this thing connects to a serial port. So you need a Java interface to the serial port like rcxcomm, and you need to write a few classes that talk to the thing (see (URL) would be nice to have some common abstractions of the RCX (...) (24 years ago, 3-Feb-02, to lugnet.robotics)
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| | Re: multiplexor and legOS
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(...) Don't ask me for a cite, but I seem to remember something about msleep only having 20ms granularity. If that's the case, your msleep(10) is either not sleeping at all or is sleeping 20ms, either one of which could cause problems. I'd suggest (...) (24 years ago, 4-Feb-02, to lugnet.robotics.rcx.legos)
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| | Re: Question?
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(...) My guess (having never looked at the schematics, or taken one apart) is that when connected backwards, "dark" would be 0V and "light" would be -8V. Again, a simple bridge rectifier (this time in the RCX) would get it sorted out. It might be (...) (24 years ago, 4-Feb-02, to lugnet.robotics)
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| | Re: Question?
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(...) What I don't understand is how this works if the sensor is connected backwards. Sure, a bridge rectifier will get the power sorted out but how does the sensor send back a voltage in the right range? If say "light" is 8V and "dark" is 0V then (...) (24 years ago, 3-Feb-02, to lugnet.robotics)
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| | Re: multiplexor and legOS
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well anyone who looked at the code I attached may have notcied that I had one of the msleeps commented out. Oops, with this now uncommented I at least see the second and third light sensors pulse on, but only for an extremely short time. Suring the (...) (24 years ago, 3-Feb-02, to lugnet.robotics.rcx.legos)
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| | This week in Robotics:
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THIS WEEK IN ROBOTICS: Here is a calendar of events coming up this week - February 2rd - 9th, 2002. Details are on our web site at (URL) you know of an upcoming event of have a robotics club or organization, please drop us a note at (...) (24 years ago, 3-Feb-02, to lugnet.robotics)
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| | Re: Power to RCX
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Regarding the data sheet for the Melexis MLX1040B that everyone is talking about, and which I've been looking for for years.... This link: (...) (URL) comes back as NOT FOUND The fact that some people are claiming to have seen it implies that it was (...) (24 years ago, 3-Feb-02, to lugnet.robotics.rcx)
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| | Vision Command $29.99 @KB Toys online
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FYI - at least their markdowns are sometimes worthwhile. This was online through what used to be eToys - any KB toys should work. Almost as cheap as the eToys markdowns. There's still the Windows 98 requirement but...... (24 years ago, 2-Feb-02, to lugnet.market.shopping, lugnet.robotics)
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| | multiplexor and legOS
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Does anyone have expierence using the active multiplexor sold by www.mindsensors.com with legOS? If you are not farmiluar with this multiplexor it is really cool as it lets you multiplex three active sensors on one port. You tell the mux which "sub" (...) (24 years ago, 2-Feb-02, to lugnet.robotics.rcx.legos)
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| | Re: "Servo" Driver for NQC
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(...) That was explained earlier. They are using an 8 bit number to store the *pattern* of the modulation. With 8 bits, there are only 8 different ratios of 1's to 0's - and one of those is to have no power at all. Hence there are seven power (...) (24 years ago, 2-Feb-02, to lugnet.robotics)
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| | Re: "Local Positioning System" for lego-vehicles with mice
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Hi, if you are interested : sources now available (URL) (24 years ago, 2-Feb-02, to lugnet.robotics.rcx.legos)
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| | LNP + USB under windows
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Hi, has anybody experience in communicating with the RCX over USB (Windows)? So far I managed to get legOS working with the USB-patch from Jin Sato; then I tried to use winLNP, but it didn't work (the light in the tower is not blinking) Now I'm (...) (24 years ago, 1-Feb-02, to lugnet.robotics.rcx.legos)
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| | Re: true tcp/ip on the RCX
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Ok, the website is up at: (URL) Christ (24 years ago, 2-Feb-02, to lugnet.robotics.rcx.legos)
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