LEGO Wear Test #2 - Design

I have the basic design  for the second LEGO wear test machine.  Here is a prototype made with Castilene plastic:

The result will be a long rig that will hold all 10 pairs of LEGO bricks to be tested simultaneously.  The parts will be made of machined metal fitting the brick shape as precisely as possible.  One thing that I learned from the first test is that it takes a lot of strength to hold those bricks, which is why I'm overkilling this one.

The bottom part is composed of two halves enabling the rig to either hold tight or release the piece completely.

Following comments that many viewers/readers have left, here are the new requirements:

• Use a rotation motion to remove the LEGO bricks.
• Keep the test speed at 10 seconds per iteration to prevent heat from friction.
• Test 10 sets at the same time.
• Test bricks from different eras.
• Once the LEGO bricks have fallen the first time, rotate them 180 degrees to continue testing until it fails again.
• Run the machine in the shed to keep the noise down.
• Have a way to query the test status while it's running.

Not following comments that some viewers/readers have left:

• This will not solve global warming
• I will keep playing with LEGO bricks
• My accent should not improve before the next test

One thing I'm leaving out is to have many control points and this test will [again] only count the iterations.  I initially wanted to monitor forces and current but it makes no sense with this simultaneous test. Next time...

For the test I've done my best to select bricks from 3 eras.  The new ones (3 pairs) were the easiest to find while the 2 pairs from the mid 70s posed a challenge.  It started with one pair I took from a set  bought at the flea market.  It was the set #370 from the mid 70s.  Looking at those two white bricks I noticed that they had a unique casting mark on one side.  After a lot of digging, I finally found two bricks with similar marks.  In a very non-scientific moment I declared that this unique feature probably means that they're from the same era.  Shoot me.

Now that the 10 pairs of bricks have been selected they are set aside until the test and other bricks are used during the rig's development.  Also, in a wave of madness, I might even run this new test twice with the side effect that I'm slowly destroying all the 2x3 bricks in the house.

Test design & LiveTankGame

Well, while I'm working on the design of the new LEGO test rig (see test1), I'm getting back into the tank project.  My generic goal for this long term project is to design a table top robotic game that will be a cross between a live card game and robotics.  So far I will have two tank platforms to test all the robotic modules so that I can prototype the gameplay based around those features.

TA1 (aka: whydontyouworkyou...)

You may ask yourself “Where the heck are you going with this?”, and that is a good question since I don't have a final answer yet.   You see, I like building stuff and I like cool-unusual-geeky-things that I can't afford so, many times, if I want something I have a tendency to build it.  My latest crazy idea came during the last Christmas vacation when my wife and I started playing a live card game called Android Netrunner.  No it has nothing to do with mobile phones.

The box

I found this game so cool that I had this crazy idea to reinvent the same level of gameplay using robots instead of cards. Why? Well... why not? Sooooo this is going to take a long time and I have to start by testing what kind of electronic interactions/capabilities the tanks can have. Once I have enough working features I will design the basic gameplay around them and build the two game tanks. Like I said... long term and so geeky that it technically falls into the nerd realm.

Here is a short update: The mobility base is composed of a robotic tank kit and a homemade DC motor driver. The motor driver PCB still needs a bit of redesign but it's functional for now and that... is good enough. Here I am building one of the two tank kits:

For now, the tank is controlled using an Android phone via bluetooth and I'm ready to start testing the other features like the laser, IR proximity sensors, light sensors, Ultrasonic range finder, etc...

Starting now, I will also tweet the updates using the hashtag #livetankgame.  

3 Great Rockets Moments

Watching the SpaceX March 7th (2013) Grasshopper test, I realized that this was one of the best rocket video moments I had seen.  Now, the minimum I could do was to list my [new] top 3.  This list is not chosen based on the historical importance of the event but on the emotional impact of seeing a rocketry  rare and amazing moment.


1
Apollo 11 landing sequence
This one may sound like an easy choice but, having read so much about the Apollo program and understanding the level of complexity of the events leading to a moon landing, this video makes me sit at the edge of my seat every time.  Especially with the added stress of the 1201-02 alarm that almost forced them to abort the landing. (info about the 1201 alarm)

2 
Space Shuttle SRB Flight
This is a long one to watch but it's worth it. The camera is attached to the top of one of the Space Shuttle Solid Rocket Boosters (SRB).  The strange feeling of seeing the ground 'fall' away at this ridiculous speed is hard to beat.  After the noisy first part of the takeoff, there is a change in the sound while the rocket leaves the dense atmosphere followed by the silence after the separation.  But the most awesome part is when the booster enters back into the dense air with the eerie moaning-sound of the empty cylinder growing into a full roar while the rocket is slowing down to terminal velocity.

3
SpaceX Grasshopper test
This video just climbed into my top three list for the simple reason that it is filmed from the air.  This was done probably by using a sort of radio controlled camera platform (e.g. Quad-copter).  It is a strange feeling, to virtually be there and float next to this monster while it just stands in mid-air.  You expect a rocket to either do nothing on the pad or go full throttle but to see this delicate precision, now that is crazy cool.  SpaceX made it look like they do this every day... but wait.. they ARE doing this every day.  Go SpaceX!

LEGO all worn out

As suggested by Christopher Gaul, I took some macro(ish) pictures of the wear patterns on both the studs of the bottom LEGO brick and the inside walls and tubes of the top LEGO brick.

Clear marks are left on the sides of the studs (top LEGO)

The small ridges on the inside walls (bottom LEGO) are visibly worn down.  There is also damage to the tubes and even the walls themselves.

Here are the 2 pictures in full resolution (sorry for the low quality) without the notes:

CSI case #66531

Adventure Time Sword

My son was invited to the birthday party of one of his friend.  His friend mentioned to him that he liked   the Adventure Time cartoon and would like to have the sword.  My son then told him that we could probably make it because we are always building stuff.

We looked it up on the web and since it's a simple shape I decided to give it a shot.  Using the hard wood from an old shelf we took down, I drew the rough dimensions on it

I then cut the rough shape using a skill saw and a jig saw

The guard was build with 2 pieces with grooves screwed and glued on both sides

This was the fun part where I sculpted all the notches and scratches followed by some sanding

It was then time for primer and painting.  The handle was done by hand using acrylic paint

This the final product after gold metallic paint and a clear acrylic coat.  The jewel was made with Super Sculpey and also painted using acrylic paint.

Action shot with my son

LEGO's magic number is 37,112

Have you ever asked yourself this question: "How many times can I assemble LEGO bricks before they wear out?"

Well... probably never but I did (on LEGO SE).  The story would end there if I had not also the knack to build a machine to test it.  Here it is:

The first version was using a metal tube attaching the top servo to the LEGO brick.  It was too flimsy and died during initial testing.  So I took an old CPU heat sink...

And using my trusty angle cutter, I made this new arm:

A successful test proved that the LEGO was no match for this chunk of aluminium.  I then made an infra-red proximity sensor to detect if the presence of the LEGO and rigged the whole thing to an Arduino.  This was shot before the test started:

and this was shot about two thirds into the testing that lasted a whopping 10 days!!!

So here are the 2 dead LEGO bricks after 10 days and 37,112 assembling and disassembling.

Don't try this at home. It's long, noisy and cruel to LEGO bricks.

In the end, both pieces failed at 50%. The studs of the bottom brick and the inside walls of the top brick are visibly worn. Both bricks can still hold on (not strongly) to normal bricks but, when put together, they can't hold. In a way, you could say that they are still in working conditions as long as they don't meet again.

Here are some more answers:

DIY desk

This is our homemade studio desk.

It's a large U-shaped desk built of plywood that is laminated with a nice wood layer. The desk (including an integrated back-shelf) is built onto the walls and has no front legs with the exception of the two end corners. This gives us more freedom of movement. We stained the desk a dark brown color to match the wood floor.

The desk also includes built-in electrical sockets, place for the printer and paper and a ventilation slit over the heater.

RoboTank #3 / motor driver version 2

Here is the second version of the programmable motor driver.

It uses a L239D chip to drive two DC motors and modulate their speed individually.   The board can be controlled with only two input wires.  This is made possible through an interface program loaded in the ATMEGA238 (same as Arduino UNO) onboard chip.  The interface chip and the driver chip are running on two separate power circuits and both are in sockets and can be easily replaced or, in the case of the ATMEGA238 chip, reprogrammed.

Using the ATMEGA238 chip makes this motor driver very versatile since 10 pins (5 digital and 5 analog) are still available for inputs/outputs.  This driver can then be reprogrammed and customized rapidly.  Here is the etching pattern I made using ExpressPCB:

Finally here's the part list:

• 1x - Small copper clad laminate board
• 1x - 16 pins socket
• 1x - 28 pins socket
• 2x - 0.1uf capacitor
• 1x - 16MHz crystal
• 2x - 6 pins female headers
• 2x - PNP transistors
• 2x - Inputs Screw Terminal 3.5mm (2 pins)
• 2x - Inputs Screw Terminal 5mm (3 pins)
• 1x - L293D (or SN754410)
• 1x - ATMEGA238P-PU
• Some wires
• (optional) 1x - Heatsink for the L293D

I'll put up a Instructables ASAP with the PCB layout file.  Until then I can send it to you if you contact me directly.