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About djm

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  1. Does the following achieve what you are looking for? Referencing your LDCAD image two posts up, click on the "bent" upwards pointing arrow in the parts bin. Keep clicking until the parts bin "Main Group" is showing. Click on the "minifig holding a magnifying glass" icon in the parts bin Click on the text in the parts bin which says "[no filter]" Tick the "Name" checkbox within the "Match" control group Enter the part number you are looking for (e.g. 32123) in the field labelled "text" and click the "Accept" command button The parts bin will then display the part (or parts) matching the given part number My apologies if I have misunderstood your question. David
  2. djm

    [GBC] The Akiyuki Project

    Mindsensors do longer ribbon cables for NXT/EV3. Refer to I've used a 3 metre one for powering a NXT motor but I've not tried it for an EV3 motor. David
  3. djm

    [WIP] Lego monorails. [Custom Rail Systems (CRS)]

    Courtesy of Hispabricks, @Masao Hidaka has very generously given me permission to make the building instructions I made of his monorail switches available for people to download. So without further ado, you will find below links to PDF file for his left and right monorail switches and his wonderful double switch. Click on the title above each picture to obtain the corresponding instructions. Monorail Left Switch Monorail Right Switch Monorail Double Switch The switches use LEGO's Power Functions medium motor, allowing them to be controlled in multiple ways. For Example, by a LEGO Infrared controller, simple switch or automated using a trigger built into a track section. Many thanks to Masao Hidaka. Regards, David
  4. HiTechnic make third party sensors for NXTs. One of their sensor’s, the gyroscope sensor, can be used to create a LEGO NXT Segway. A video of their model is available Additional details and building instructions are available at Having seen how much enjoyment my children had when playing with this model, I decided to build some for a show being run by my LUG. I endeavour to provide the public an opportunity to interact with my displays, on the premise that it is more interesting for them. While testing the models prior to the show, I identified some minor alterations to HiTechnic’s program which appear to improve the stability of the Segway. The remainder of this post describes some observations about running the model and alterations which were made to the original program. But first, Cutting to the Chase If you’re more interested in running the modified program rather than reading the rest of the post, download this zip file and follow the instructions in the readme.txt file to install the program on your NXT. General Observations 1) Having similar motor speeds helps The robot stability seems to improve if the two NXT motors rotate at close to the same speed. An issue of differing motor speeds is described here and includes some techniques you may wish to try to better identify suitable motor pairs. Alternatively, within the zip file identified above, there is a program named rotation_count. You can install it, connect one motor to the A port and one to the C port and run the program. The program will identify the number of rotations each motor makes in 20 seconds. The closer you can get the numbers to match, the closer the motor speeds should be to being the same and the more stable the robot appears to be. 2) Battery charge level matters I tend to run my NXTs with the rechargeable battery pack. It is noticeable that when the robots have been running for a considerable duration (hours), they become more prone to falling. This is resolved instantly by replacing the rechargeable battery pack with a fully charged battery pack. Program Tweaks I made a couple of tweaks to the program. One was to try to improve the stability and the others to enhance the usability. a) Gradual Speed Change The original program treats the command from the Infrared remote as an instant command. The two lever IR controller has three speed values; -7 (backwards), 0 (neutral) and 7 (forwards). If the Segway is travelling backwards and both levers are pushed forward, the Segway responds by changing the motor direction at full throttle i.e. from -7 to +7. The modified program treats a change in the IR remote lever position as a speed delta change. When the Segway is travelling backwards and both levers are pushed forward, the Segway responds by changing the motor speed and direction in single increments i.e. -7, -6, -5, -4, …, 4, 5, 6, 7. This results in a more gradual acceleration/deceleration for the Segway and less “rocking”. b) Prompt for IR Channel The modified program begins by prompting for which IR channel number you want to control the Segway with. This allows multiple Segways to run concurrently using independent IR remote controls. c) Continue After Falling When the Segway falls, the original program displays a message and then exits once the NXT’s “return” key is pressed. The modified program displays the same message but then loops back to the point where the Segway is stood up. This alteration makes it easier to continue running the program when it is under the control of a member of the public e.g. at a display. Demonstration The following video is split into 3 segments. They illustrate; the impact of having a low battery (segment 1) the benefit of a fully charged battery (segment 2) the behavioural difference between the original program (yellow Segway) and the modified program (white and red Segways). The difference is most noticeable toward the end of the segment. The yellow Segway will start and stop turning before the other two Segways. Similarly, the yellow Segway will begin to move forward and backwards sooner than the red and white Segways, which results in it swinging more. If you have any questions about anything above, please post them here and I will do my best to answer them. Regards, David
  5. djm

    [WIP] Lego monorails. [Custom Rail Systems (CRS)]

    Welcome to EuroBricks. I'm happy that you have joined as your monorail designs have been inspirational to a number of us. I was inspired by your videos to create building instructions for your single and double monorail switches. I have not made the building instructions available for downloading as they are your design and I did not have your permission to make them available for people to download. With your permission, I would like to post links to these instructions in this forum so that other builders could see how they are built. I sent you a similar personal message but I had forgotten that until you get to 10 posts, I think you are unable to use the messenger. Regards, David
  6. The Auckland LEGO User Group is holding its annual Brick Show on November 3rd and 4th. This year our show will take place at the North Shore Event Centre in Auckland. Please visit for more information about the show, including pre-show ticket sales. Thank you.
  7. djm

    [GBC] Cardan Lift

    Try here for a BrickStick parts list, which BrickLink should be able to upload. I just created it from the LDraw mpd file, via Rebrickable. Rebrickable is my "go to" place for parts list building these days as it is very easy to import models, correct part errors (e.g. colours) and then create other output formats by exporting from Rebrickable. David
  8. My R56 order was delivered (to New Zealand) two days ago. Very nice indeed. Now I'm just hanging out for the R72 and the R88 production to commence. David
  9. djm

    [GBC] The Akiyuki Project

    Unfortunately not. The photos that did exist for it were from a public display run by my LUG. Somewhere along the way, the LUG photo galleries were lost during a web site upgrade. I had dismantled it and used the parts for building other things in the meantime as I couldn't get it running reliably enough for use in a public display. I agree that the pricing is reasonable. Considering the time it would take to reverse engineer and then create the building instructions, I'm happy to to purchase the instructions (and have in fact already done so). As your subsequent post says, one can always reverse engineer the build from the video. David
  10. djm

    [GBC] The Akiyuki Project

    I agree wholeheartedly with @RohanBeckett, @Berthil and @Ankoku, building the Ball Factory as your first build will likely be somewhat challenging. The other thing to bear in mind if you are going to build it in red is that one to two parts may be pricey compared to other colours. Writing as someone who built their Ball Factory in red, the price of the Technic 1x14 brick can be a bit eye-watering. Good luck, enjoy your building and welcome to EuroBricks. David
  11. djm

    First MoC 20 years ago

    I can do an old picture (well video) but not of a MOC. Try LEGOLAND in 1969: I had just turned six. This was shot by my dad on a cine camera (hence no sound) and I had it transferred to a DVD a few years back. David
  12. djm

    [WIP] Lego monorails. [Custom Rail Systems (CRS)]

    If you want some building instructions made for those two new switches, drop me a line. David
  13. 7939 - Cargo Train (Train / RC Train) Download MPD Known errors: No stickers No string No train track parts 2x Orange minifig torso used as patterned torso unavailable as LDraw part 1x Yellow plain minifig head used as head unavailable as LDraw part Built with LDCAD 1.6b
  14. djm

    [WIP] Lego monorails. [Custom Rail Systems (CRS)]

    Four of these curves are required for a 180 degree turn, so eight for a full circle. The diameter of the curve (centre of track to centre of track) is roughly 1950 LDUs i.e. 97.5 "studs". David
  15. Possibly ? Only available in yellow though. Via rebrickable, the LEGO id looks to be design number 10015 and (for the piece in yellow) via LEGO's Bricks and pieces, an element number of 6000284. David