Calder Valley Brick Show 2025

So yesterday was the annual LEGO show over in Mytholmroyd. As usual, a superb but tiring day – I’m not used to 9 hours on my feet 🙂

Surprisingly we went the whole day and didn’t need a single change of batteries, which given that the remote control bots were in non-stop use was rather amazing.

I re-programmed my Bra1der with Pybricks (beta) the week before the show. That proved to be a very good thing. The braider just got on and did its job. No misaligned bobbins going between the slots due to motor overshoots, or weird random slow-downs that the original LEGO firmware used to suffer from. I even tried one of the braids it had been programmed with but I’d never got around to trying. I think it looks rather funky:

I did have a few issues with some of the bots going a bit potty but nothing insurmountable. The Mindcub3r did go through a period where it wasn’t solving cubes at all – not sure what was going on there. The only thing I can think of is that the EV3 was still set to a 30 minute sleep, so maybe the internal solver was getting killed? Who knows. I did have one casualty. The 3D art pen in the EV3DPrinter blew itself up:

The nozzle got blocked and the filament feed, being at the back, managed to pop the end off. So that was that for the 3D printer for the day. That was a shame as I like having that running. I have done some maintenance on the pen today, so I hope that will be back in operation for the next shows.

The loom behaved itself perfectly. It probably wove the best scarf it’s ever done! It still had yarn left in the bobbin frame at the end of the day, so I wasn’t able to finish the scarf during the show. I think that’s down to me starting the loom at 11am. I know that a 9am-5pm show will result in a completed scarf.

So, whilst I sit here and type, it’s currently doing a bit more weaving. I’ll finish it off in the next day or so, take some photos, and get it up on eBay with all the proceeds going to the Forget Me Not Children’s Hospice charity. So watch this space for the eBay link!

Calder Valley Brickshow Scarf Update #1

Yesterday I showed several of my robots at the Calder Valley Brick Show, during which my Weav3r loom was making a scarf. This time around I have decided that I shall be auctioning the scarf, via eBay, and the proceeds going to the charity supported by the show: Forget Me Not Children’s Hospice

The loom didn’t quite finish the scarf during the event. As can be seen from the photos, above, there is still a little warp yarn left on the bobbins. I shall complete the scarf over the next couple of days and post an update with photos of the scarf and a link to the eBay auction then.

Braill3 – An EV3-based Braille Bricks Reader

Several months ago I had been thinking on building a robot that could read the Braille bricks developed by LEGO. They have had them available in a more educational context via their https://legobraillebricks.com/ website for some time now. Unfortunately, these ideas came to nought at that time, so I put the idea to bed.

Roll on a few months and the group of RobotMak3rs that I’m a member of had one of their regular remix challenges – i.e. to mix an existing set with some robotics to come up with a new idea. By then the domestic LEGO Braille Bricks set (40656 in the UK) was out, so I figured it was time to revisit my earlier ideas.

Initial Ideas

Right at the start I wanted the bot to read out the Braille using text-to-speech (TTS). I wanted to do this as the bricks are intended for visually impaired users so having just display of text would be inappropriate. The Spike/Robot Inventor doesn’t have the ability to generate complex sounds on the hub itself and would have relied on an external app running on a mobile or table to perform that task. Instead I decided it would be far better to use an EV3 running Pybricks micropython as that has the ability to perform TTS output. In addition to wanting the Braille read out, I wanted all the prompts that would appear on screen to have an audio equivalent.

My initial idea for the mechanics was to have three medium EV3 motors each with 3×5 L-beam attached. As the bot moved along the line of Braille it would rotate the motors such that the tip of an L-beam touched either the brick’s stud or the top of the brick. The difference in angle of the motor would indicate a dot or not. However, very quickly this idea was discarded due to the fact that the stud height is only 1.7mm. The height, and therefore angle change was not sufficient to accurately distinguish the presence of a stud or not. Also this would have required three motors, only allowing one remaining to move the bot along a row. Since I wanted to have it be able to read multiple rows of text, I’d have needed 5 motors (X, Y, +3 for touch) which is not possible with an EV3. So I discarded this approach.

My next idea was for a bot that had an arm with three touch switches mounted on it and have the arm lift up and down. This way the angle of the motor would be irrelevant. The arm would need to move up and down on to each column of studs so that it wouldn’t get snagged on the next column as it moved sideways.

I went through various arrangements of the switches, settling on something similar to below for a number of prototypes:

The principle here was that the stud would push against the pin, which in turn via rotation of the 3×3 quarter circle beam would press in the button. The motors would have had to be mounted at 90° to each other due to the width of the switches (initially) preventing them being next to each other. The big problem with all of these designs is that the springs in the switches are remarkably firm. The motor, pushing the arm down, would have to apply a significant force – akin to trying to hold out a 1kg mass at arms length. Also, it looked ugly. I tend to work on the principle that if it’s ugly then it’s likely to be wrong.

The ‘Fingertip’

After going through several iterations of the ideas above, I had a brainwave. It was possible to mount the motors in parallel and ‘dog-leg’ the pins such that they could also touch the studs. To counter the issue of the required force to press in the switches, linear actuators would be used instead. Although this would slow down the sensing action it would trade speed against accuracy. I ended up with the mechanism below:

This mechanism worked perfectly, with an unexpected discovery on the switches, discussed further on.

Bridge, Switches, and Calibration

The Braille sensing mechanism (the ‘lift’ as I think of it) needed to move in both X axis and Y axis, so that the several rows of bricks could be placed on the baseboards supplied with the kit. The lift would be mounted on a bridge, allowing for Y-axis movement, and the bridge itself would move in the X-axis. The bridge took a few attempts to get right. Due to a combination of the mass of the lift and the force required to press in the switches resulted in flexing of the bridge, so this required a few revisions to get it rigid enough but not too bulky

One thing I had never realised about the EV3’s switches is that they trigger at the start of their travel, i.e. they don’t need to be pushed all the way in to trigger. Had they needed to be depressed all the way, it’s quite possible this model would never have worked. Due to LEGO being plastic, the parts are never perfectly aligned. This could have meant that one of the switches may have reached the end of its travel before either/both of the other switches had triggered. No amount of extra downward force could have pressed the other two as this switch would have blocked any more movement. Thankfully they trigger at the start, so it’s still possible to push down, thus enabling the neighbouring switches to also trigger.

Due to slight flex in the model, it’s not possible to have the motor wind the linear actuators to the same place per row of Braille. The middle two rows can require a little more force. To solve this the bot requires calibration on first use, and offers to calibrate on start up as well. Calibration requires that an L (⠇) brick is placed at the start of each row, then the bot tests each of those bricks. For each row the motor position for the last switch to activate is stored on disk, for repeat use, then when in use it drives the motor to just beyond the motor angle to ensure that all switches could be activated.

Accessibility

As I said at the start, I wanted this model to be accessible to the target users, so all instructions are read out as well as displayed on screen. All button operations have a small click to provide audio feedback, along with a relevant audio prompt, e.g. saying which row has been selected to read. To aid in placing the Braille bricks on the baseboard there are tiles on the first column. Subsequent bricks are simply placed next to the previous bricks. The EV3 has been oriented so that the speaker is facing the user so that it can be heard.

Video

As part of our group’s remix challenge we have to produce a video relating to our build. I opted to have the video show parts of the robot and it in operation. Since the bot converts the Braille to speech, I figured I’d have the voice-over performed by the bot as well (I’m never a fan of speaking on camera, and being a Brit I always feel that I sound sarcastic 😆). I also thought that it would be a fun little feature to have the subtitles show in Braille first and the wipe over to the actual text. The resulting video is below:

Build Instructions and Code

Build instructions: http://jander.me.uk/LEGO/resources/Braill3-BIs.pdf

Python code: http://jander.me.uk/LEGO/resources/braille.zip

The Python code needs to be run under Pybricks micropython, under ev3dev. This requires a microSD card. The official LEGO ev3dev installation can be found at: https://education.lego.com/en-us/product-resources/mindstorms-ev3/teacher-resources/python-for-ev3/

Operating Instructions

  • On first ever run of the program, it will pre-generate all the pre-coded speech prompts. This is so that the program doesn’t have to perform the TTS step every time a common speech prompt is needed. It will only do this the once.
  • On first run of the program it will insist on a calibration step. It will offer to perform a calibration on every other run, but it defaults to ‘no’. To calibrate perform the following:
    1. Put an L brick at the start of each of the 4 rows
    2. Press the centre button. This will then test each of the sensors and motor and store for future use
  • Lay out the Braille as wanted. There are 4 rows that can be used. Select the row to be read with the left and right buttons, centre to read. Spaces between words can be either one or two columns of studs wide. Three or more empty columns will end the row of text.

Robot Olympics Remix: Eque5trian – Show Jumping

In March 2021 the members of the RobotMak3rs RLOC were challenged to come up with ideas for an Olympic Games remix involving two kits, one robotic and one non-robotic. My idea was to mix the LEGO White House (21054) kit:

and the Robot Inventor (51515) kit (plus four pulley wheels):

to create an Olympic Show Jumping model:

Model Modes

The model has two modes of operation: automaton and game. In automaton mode, the horse will go around the arena leaping over the jumps of its own accord. In game mode, there are speed and jump controls and the player attempts to get the horse’s speed right and jump at the correct time. A video showing the model in operation and some of the details about it is below:

Model Operation

What was not shown in the video is how to start the model off. The model needs to set its initial positions. It does this by rotating the jump motor to its 0° position, then repeatedly rotating the horse motor to its 0° position until the horse ends up in its start position. This is required due to the 36T:60T gearing used to drive the horse’s position. The colour sensor will detect the white 3L beam when it’s in the start position.

The steps to start the model off are:

  1. Before starting the code, remove all the jumps – so that they don’t get knocked over during initialising.
  2. Start the program. The horse will go through its location detection steps.
  3. Replace all the jumps back to their positions
  4. Tap the hub – it waits for a tap gesture before carrying on
  5. Enjoy the model’s action.

Build Instructions and Code

I have produced build instructions which are linked to below. There are two programs, one for each mode that are also available below. The code has been written in the default block language for the 51515 hub. My BIs and code are released under the Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International licence:

Other Model Submissions

Other models from both the Robotmak3rs and the general community can be found at: https://www.facebook.com/hashtag/robotmak3rsolympics

Robot Inventor: Pass the Build – Charlie

Over the past week or so, several members (including me) of the RobotMak3rs RLOC have been having a lot of fun playing with LEGO’s new Robot Inventor kit (51515), which will be released on 15th October this year. Many thanks goes to LEGO and the RobotMak3rs RLOC for supporting our ideas.

My idea was for us, as world-wide community, to have fun building some of the models together. Here’s the first of the videos – Charlie:

Pass the Build of Charlie

Watch this space for the other models!

The RobotMak3rs Community Facebook page can be found here: https://www.facebook.com/robotmak3rs/

#mindstorms #robotinventor #robotmak3rs

Weav3r Cloth Winding Drum Update

A little while ago I posted about my new cloth winding drum. Up until that point a lot of it had been built, but I still didn’t have any of the 1L worm gears needed to drive the turntable ends to the drum. Only the 3D LDraw model showed that it’d work.

Since then, I’ve given in and ordered some via BrickOwl. I finally had the opportunity to test the build out and, unfortunately, it didn’t work as intended. The turntables could easily skip off the worm gears under load – loads which it’s likely to see in operation due to the tension in the warp threads. A little bit of investigation showed that the structures that were holding the worm gears in place were flexing under load. There was nothing to stop the split cross-blocks from rotating a little. Since then I’ve redesigned that section to stop that rotation:

Worm gear support.
Redesigned worm gear support

This appears to work perfectly 🙂 . Without risking breaking something, I am unable to cause the worm gears to skip on the turntables.

A few photos of the real cloth drum and its update:

Complete cloth winder, with drum in-situ.
Drum removed.
Drum removed.
New worm gear and its strengthened support.
Worm gear meshing with the drum’s left turntable.

The LDraw model has been updated to include the new support:

http://jander.me.uk/LEGO/resources/Cloth%20Winder.ldr

This work is released under the Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International licence.

EV3DPrinter Build Instructions (variant)

For some time now I’ve been using the excellent EV3DPrinter, designed by Marc-André Bazergui. The original information on this model can be found at https://www.instructables.com/id/NEW-EV3Dprinter/

To help rebuild his model, Baz had produced a 3D model made in LEGO Digital Designer. That software is almost, if not, obsolete so it’s not so easy now for others to rebuild his model. When I’ve shown it working at exhibitions there has been great interest from people about building their own copy of it – to which I’ve responded that I really ought to make a step-by-step PDF of it for others to follow. I have finally done that.

My build of the EV3DPrinter has been modified. A few sections of it have been altered, and other things have been moved around – e.g. the Y-axis touch sensor is in a different location. In addition to changes to the model I wrote all my own code from scratch, so my sensor and motor ports are different to the original. In addition I have made BIs for an additional pen-holder for a different type of 3D pen.

The BIs for the main model can be obtained from:

http://www.jander.me.uk/LEGO/resources/EV3DPrinter%20JN.pdf

The BIs for the Type 2 pen holder can be obtained from:

http://www.jander.me.uk/LEGO/resources/Pen%20Holder%20Type%202.pdf

The EV3g code can be obtained from:

http://www.jander.me.uk/LEGO/resources/EV3DPrinter_JN.ev3

Additional to the EV3 code you will need some data files for the 3D models, such as the letters or the castle:

These data files are in a zip file that will need to be extracted and all .rtf files downloaded into the EV3 in the same folder as the main code. This file can be obtained from:

http://www.jander.me.uk/LEGO/resources/EV3DPrinter_JN_Data.zip

There are several programs:

  • Basket Body
  • Basket Lid – These two combined make a small basket with fitting lid
  • Tubes – A pair of intertwined tubes, a bit like Penne pasta 🙂
  • Stars – Make various pointed stars / cones
  • 3D model – choose a test, boat, castle, and the parts for the FLL logo
  • Letters – a menu of letters, for which the height can be changed

When the program starts it will initialise the mechanism. Both the X-axis and Z-axis have adjustable axle stops. The X-axis stop may need to be adjusted to get the base plate central. The Z-axis stop will most definitely need to be adjusted to get the tip of the pen close to the plate. My advice, before starting any printing runs, to manually move the Z-axis elevator to get the pen to the correct height and then alter the sensor axle at the back so that the touch sensor is just pressed. This will ensure that when you start the program that the pen isn’t accidentally driven in to the plate, or that the pen is too high.

After initialising, the program will ask what type of pen is in use: “press and hold” or “on / off”. The original type of pen, as shown on Baz’s instructions, was a “press and hold” version. The 2nd type of pen I have, you press once to start and press again to stop. The program will need to know what style you’re using. The EV3 will remember your last choice and pre-select that at the start of each program.

This work is released under the Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International licence.

Bobbin Wind3r Code & BIs

Over the past few weeks I’ve been working on a robotic bobbin winder for my Weav3r loom. Previously, at shows, I’ve had a simple motorised mechanism for winding them but it required my attention to wind. After regular suggestions from Martyn Boogaarts about making a bot to do it, I finally pulled my finger out and got on with designing one:

My intention is to ultimately release the BIs for the loom, but it is taking some time to construct the 3D models for it. One of the issues with the loom is that I’ll need to dismantle significant portions of it to find out how I built it 🙂

I mainly model things for my own benefit so should I have a need to rebuild, I can. For this model, I figured I’d actually produce a proper BI PDF and release that and the code for those that wish to have a go at building it. I should note that I have been a little lazy with the BIs and not run any cables. Instead I have inserted the cable ends and colour-coded them. You will need 1x 50cm, 1x 35cm, and 4x 25cm cables – I’ll leave the routing of them to the builder.

This model will probably need an instruction manual, although I’m hopeful that it ought to be relatively clear how it works. The video above shows how the yarn is threaded through but that ought to be obvious. The code has a menu system which also ought to be clear. If there’s enough feedback/demand for operation instructions, I’ll write up a blog article/document to do that.

The code and model are released under the Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International licence.

The code can be obtained from: http://jander.me.uk/LEGO/resources/Bobbin%20Wind3r.ev3

The BI PDF can be obtained from: http://jander.me.uk/LEGO/resources/Bobbin%20Wind3r.pdf