Some of us have been behind the scenes for a while, dealing with the latest issue found on the LPF family... At mid October a Polish AFOL found one potential problem with the new PF V2 Receiver (released with the 9398, 4x4 Crawler) when there are two PF M-motors connected to one of its outputs. The issue can be put shortly like this - When two or more Medium motors are connected to a single output of the V2 Receiver (no matter which one), they often make a squeaking sound instead of starting, and only start after some time, or if forced by hand. Even after they finally start and then stop, the problem occurs again. Today after having concluded their own investigations, the Technology Platform Team came-up with one official statement about this issue, signed by Gaute Munch as usual. LEGO Power Functions V2 RC Receiver There has been some confusion regarding the new LEGO Power Functions V2 RC Receiver that is released in the Technic 9398 4X4 Crawler. This component is currently only available through the 9398 set, but was not made exclusively for this product.
The V2 RC Receiver is updated with a CMOS motor driver giving less power loss. This is done to improve the user experience with longer battery lifetime and better motor performance. Unfortunately it has the drawback that it is not able to start 2 or more LPF Medium motors at the same output. As I will explain below this is not a problem with the motor driver, but a known issue with the LPF Medium motor. The raw motor currently used in the LPF Medium motor internally contains a relatively large capacitor (1 uF) across each of the 3 motor coils. This is done by the motor manufacturer for noise reduction. We knew that this would be an issue with the new CMOS motor driver (DRV8833). Since it can source a very high inrush current the over current protection will kick in sooner (typically after 2,25 us with a current exceeding 3,3 A). At start up the motor driver will first charge the input capacitance. With 2 or more LPF Medium motors at the same output this can trigger the over current protection.
It will repeatedly try to start the motors and you will only hear a singing noise. For many reasons we have been searching for a higher quality solution for the LPF Medium motor and we now have an approved new raw motor. It has better quality commutation and only 1nF across the terminal. An updated LPF Medium motor will be released during 2013. Backwards compatibility is of very high importance when we choose new solutions. In this case our decision was that the advantages of the new motor driver together with the fact that we would update the LPF Medium motor would compensate for the inconvenience with the current LPF Medium motor. We hope this is not causing too many limitations to your model creativity. We guess the Tech Platform team has been frantically searching for a replacement for the raw Medium motor, in the last weeks. Although the problem has been identified a the solution as well, we will remain with a legacy of 'not so compatible PF elements'. At this point and thinking on the possible remedy, I can only wish TLG will make the new version of the PF M-motor easily distinguishable from the original version actually in the market.
We had already two versions of the PF IR Receiver (with firmware differences only) and two versions of the large Technic Linear Actuator, which are inconvenient enough to distinguish... TechnicBRICKs contents may be sporadically updated, if the authors finds further relevant info about a certain post, or content/spell mistakes. Hence please don't be surprised if you find few changes at later visits, relative to a previous read. TechnicBRICKs often shows other peoples' creations and/or images. We always try to credit the author(s) and link to their main publishing website, and if possible with their name in real life. Since this is not always possible, we request that if you find something here that is yours or from someone you know, you leave a comment on the respective post and claim the authorship. TechnicBRICKs is optimized for Firefox 16.0 and 1600x1200 resolution displays or wider. LEGO® is a trademark of The LEGO Group of companies which does not sponsor, authorize or endorse this blog.
LEGO, the LEGO logo, the Brick and Knob configurations, the Minifigure and MINDSTORMS, are registered trademarks of The LEGO Group. Original LEGO images are copyrighted by The LEGO Group and are used here in accordance with their fair play policy.$54.95 Multiplexer for NXT/EV3 Motors Model: NXTMMX-v2 Quantity: 482 ItemsWith this multiplexer, you will be able to connect two additional motors to your NXT/EV3.Connect NXT Motors and/or EV3 MotorsCompact, Easy to Integrate DesignEasy to ProgramRequires external battery Quantity: With this multiplexer, you can connect two additional motors to your NXT.It also has a pass-through Digital Sensor Port to connect more sensors/multiplexers. (On this sensor port, you can daisy-chain more multiplexers to connect additional motors.)pact, Easy to Integrate DesignEasy to ProgramUse with NXT, EV3, EVShield, and PiStormsSupported in EV3G, NXT-G, NXC, RobotCUses external power supply/battery for motorsSoftware & Driver DownloadsNXTMMX - User GuideHow to Install NXT-G blocksHow to Install EV3-G BlocksRobotC (4.28+) Driverev3dev classev3dev tutorialsLeJOS SamplesNXTMMX EV3 blockYou may also needTo power the motors attached to NXTMMX, you will need a battery pack.
You can order a 6-AA battery holder here.8. Troubleshooting Common Problems with the BrickPi 8. Troubleshooting Common Problems with the BrickPi Find out how to access preview-only content ChapterAutomation, Communication and Cybernetics in Science and Engineering 2011/2012 pp 315-32320 December 2012Problem based learning of object-oriented Programming with LEGO Mindstorms and leJOS * Final gross prices may vary according to local VAT. Problem based learning has proved to be a powerful educational approach to successful and effective teaching. Experiences worldwide have shown the attraction of robotics and the improved motivation of students dealing with robots. Problem based learning (PBL) as well as robotics are usually applied when dealing with smaller groups of students. However, in the first year of study student numbers of more than 1000 are a common phenomenon for lectures in mechanical engineering. This paper introduces a setup for teaching object-oriented programming based on programming LEGO Mindstorms NXT robots for large scaled groups.