LEGO Conveyex Imperial Transport

Este artigo é a parte 1 de 1 da série  Conveyex

So another never-to-be-completed project.

I like Star Wars but usually don’t care for LEGO Star Wars sets. But when the Conveyex set was released I liked it a lot. Probably because it looked like a monorail train and I was already gathering a few old LEGO monorail pieces. So I ordered one… or so I tought.

When I order from LEGO I take the chance to buy a few MINDSTORMS motors and some Power Function elements like cables or batteries. I had a few items already on my desired list so I didn’t notice exactly how many items I was ordering… and so I received 3 (three!) Conveyex sets.

Oh boy. What I am going to do with all these Conveyex?

Then I realized that the size of the set wagons is simillar to the monorail wagons. After assembling the first set I took off the wheels and with just a few extra bricks I got my first monorail version:

Since I was already trying to use Powered Up as a way to control the monorail motor it seemed natural to extend this first version to a bluetooth controled one:

This way the Conveyex could be controlled not just with the Powered Up train headset but also programmatically. That would allow me to use the Conveyex on a large animated diorama, with MINDSTORMS and other controllable elements:

So this was the beginning. Now I “just” needed to extend the train with a few more wagons. And the rail with a few more tracks. Seemed simple.

But the old LEGO monorail system wasn’t meant for long trains. The system was designed for just 1 engine in the middle and 1 wagon at each side:


The wagons connect to the engine through a custom coupling system. As far as I know, there is no way to connect other LEGO elements to the engine couplings. Extending the length is possible by adding wagons and using some LEGO parts as custom couplers, like in LEGO trains.

Fortunately there is a company named 4DBrix that sell a few custom elements compatible with the monorail system. I ordered them some car extensions that has a “male” tab that connects to the engine and a “female” socket that allow extra wagons to be added. It worked but then the overall weight started to be feel too demanding for the monorail motor. Perhaps a single motor could move a train with 2 or 3 wagons and an engine but I also wanted ramps (of course!) and that seemed too much. So I wondered if it is possible to use more than one monorail motor…

It is:

The monorail track is really just a long gear. So the two motors are directly coupled together and just add their force (oh well… after a while I found out that this is not always true).

But the way that the Powered Up Hub was designed it is not the best for such a setup – the 6x AAA batteries would drain too fast and I would have to remove the Hub to replace them. Once in a while it might be acceptable but certainly not every 30 minutes. The good old Power Functions LiPo battery is much better – it allows in place recharging and it also looks like it can supply a few more milliamps than the PUP Hub (not confirmed).

So I picked my LEGO relay idea and built a Powered Up version:

and then applied it to the Conveyex:

So now the Powered Up Hub batteries are only used to keep the Hub ON and sometimes to change the relay state. Need to measure it but I suspect that it would work a few hours. And no custom cable is used, just 100% LEGO electric parts.

So today the Conveyex is already looking good:

The model uses 2 monorail motors, 4 wagons and an engine car:

From left to right:

  • Powered Up Hub wagon
  • Monorail motor
  • Relay wagon
  • Power Functions LiPo battery wagon
  • still no purpose wagon
  • Monorail wagon
  • Engine car

So the Conveyex is really just 2 monorail trains linked together (in the above drawing, the extra space reflects the custom coupling I had to build, longer than the monorail coupling sustem). The wagons aren’t all of the same size because the wagons length from the LEGO Conveyex are in facto a bit too larger and make the monorail derail at regular curves and ramps – so I built the Relay wagon 4 studs shorter.

The weight is not equally distributed, the front train is lighter than the back train. So sometimes, when the Conveyex is moving on ramps, the two trains move at different speeds – like when the front train already reached the top and the back train is still moving up in the ramp:

On the video above the LiPo was adjusted for 4/7 of output power. The front train gained too much speed and the monorail coupling couldn’t handle and disconnected. Now I’m running the Conveyex with the LiPo at 5/7 of output power and this never happened again but probably will need to add more weight to the “still no purpose wagon”… crazy ideas welcome 🙂

LEGO WeDo 2.0 – playing sound

Este artigo é a parte 4 de 6 da série  WeDo 2.0 - reverse engineering

Great news – LEGO Eduction released the WeDo 2.0 SDK today!

After digging into it, I found the information needed to control the Piezo: as expected, it’s controlled by the same handle that is used for controlling the motor and the RGB LED (0x003d). The “port” is “05” and the “command” to activate the Piezo is “02”, followed by a payload of “04” bytes containing:

  • the Frequency in Hz (2 bytes, reversed)
  • the duration in ms (2 bytes, reversed)

So to play a “C” (or “Do”, 261 Hz) during 1/8 of a second (125 ms) we use this command:

[A0:E6:F8:1E:58:57][LE]> char-write-cmd 003d 050204B801E803

So let’s hear the very first music played by a WeDo 2.0 from a linux shell script:

#!/usr/bin/env bash

# In Ubuntu run this script with sudo
# "Imperial March on a WeDo 2.0" was inspired by https://gist.github.com/tagliati/1804108

# command: gatttool -i hci0 -b A0:E6:F8:1E:58:57 --char-write-req -a 0x003d -n 050204

# beep(a, 500) 
gatttool -i hci0 -b A0:E6:F8:1E:58:57 --char-write-req -a 0x003d -n 050204B801F401
sleep 0.5

# beep(a, 500) 
gatttool -i hci0 -b A0:E6:F8:1E:58:57 --char-write-req -a 0x003d -n 050204B801F401
sleep 0.5

# beep(a, 500) 
gatttool -i hci0 -b A0:E6:F8:1E:58:57 --char-write-req -a 0x003d -n 050204B801F401
sleep 0.5

# beep(f, 350)
gatttool -i hci0 -b A0:E6:F8:1E:58:57 --char-write-req -a 0x003d -n 0502045D015E01
sleep 0.35

# beep(cH, 150)
gatttool -i hci0 -b A0:E6:F8:1E:58:57 --char-write-req -a 0x003d -n 0502040B029600
sleep 0.15

# beep(a, 500)
gatttool -i hci0 -b A0:E6:F8:1E:58:57 --char-write-req -a 0x003d -n 050204B801F401
sleep 0.5

# beep(f, 350)
gatttool -i hci0 -b A0:E6:F8:1E:58:57 --char-write-req -a 0x003d -n 0502045D015E01
sleep 0.35

# beep(cH, 150)
gatttool -i hci0 -b A0:E6:F8:1E:58:57 --char-write-req -a 0x003d -n 0502040B029600
sleep 0.15

# beep(a, 1000)
gatttool -i hci0 -b A0:E6:F8:1E:58:57 --char-write-req -a 0x003d -n 050204B801E803
sleep 1.0

# beep(eH, 500)
gatttool -i hci0 -b A0:E6:F8:1E:58:57 --char-write-req -a 0x003d -n 0502049302F401
sleep 0.5
    
# beep(eH, 500)
gatttool -i hci0 -b A0:E6:F8:1E:58:57 --char-write-req -a 0x003d -n 0502049302F401
sleep 0.5

# beep(eH, 500)
gatttool -i hci0 -b A0:E6:F8:1E:58:57 --char-write-req -a 0x003d -n 0502049302F401
sleep 0.5

# beep(fH, 350) 
gatttool -i hci0 -b A0:E6:F8:1E:58:57 --char-write-req -a 0x003d -n 050204BA025E01
sleep 0.35

# beep(cH, 150)
gatttool -i hci0 -b A0:E6:F8:1E:58:57 --char-write-req -a 0x003d -n 0502040B029600
sleep 0.15

# beep(gS, 500)
gatttool -i hci0 -b A0:E6:F8:1E:58:57 --char-write-req -a 0x003d -n 0502049F01F401
sleep 0.5    

# beep(f, 350)
gatttool -i hci0 -b A0:E6:F8:1E:58:57 --char-write-req -a 0x003d -n 0502045D015E01
sleep 0.35

# beep(cH, 150)
gatttool -i hci0 -b A0:E6:F8:1E:58:57 --char-write-req -a 0x003d -n 0502040B029600
sleep 0.15

# beep(a, 1000)
gatttool -i hci0 -b A0:E6:F8:1E:58:57 --char-write-req -a 0x003d -n 050204B801E803
sleep 1.0
 
# beep(aH, 500)   
gatttool -i hci0 -b A0:E6:F8:1E:58:57 --char-write-req -a 0x003d -n 0502047003F401
sleep 0.5

# beep(a, 350) 
gatttool -i hci0 -b A0:E6:F8:1E:58:57 --char-write-req -a 0x003d -n 050204B8015E01
sleep 0.35

# beep(a, 150)
gatttool -i hci0 -b A0:E6:F8:1E:58:57 --char-write-req -a 0x003d -n 050204B8019600
sleep 0.15

# beep(aH, 500)   
gatttool -i hci0 -b A0:E6:F8:1E:58:57 --char-write-req -a 0x003d -n 0502047003F401
sleep 0.5

# beep(gSH, 250)
gatttool -i hci0 -b A0:E6:F8:1E:58:57 --char-write-req -a 0x003d -n 0502043E03FA00
sleep 0.25

# beep(gH, 250)
gatttool -i hci0 -b A0:E6:F8:1E:58:57 --char-write-req -a 0x003d -n 0502041003FA00
sleep 0.25

# beep(fSH, 125)
gatttool -i hci0 -b A0:E6:F8:1E:58:57 --char-write-req -a 0x003d -n 050204E4027D00
sleep 0.125

# beep(fH, 125) 
gatttool -i hci0 -b A0:E6:F8:1E:58:57 --char-write-req -a 0x003d -n 050204BA027D00
sleep 0.125  
   
# beep(fSH, 250)
gatttool -i hci0 -b A0:E6:F8:1E:58:57 --char-write-req -a 0x003d -n 050204E402FA00
sleep 0.25

# delay(250)
sleep 0.25

# beep(aS, 250)
gatttool -i hci0 -b A0:E6:F8:1E:58:57 --char-write-req -a 0x003d -n 050204C701FA00
sleep 0.25

# beep(dSH, 500)
gatttool -i hci0 -b A0:E6:F8:1E:58:57 --char-write-req -a 0x003d -n 0502046E02F401
sleep 0.5

# beep(dH, 250)  
gatttool -i hci0 -b A0:E6:F8:1E:58:57 --char-write-req -a 0x003d -n 0502044B02FA00
sleep 0.25

# beep(cSH, 250)  
gatttool -i hci0 -b A0:E6:F8:1E:58:57 --char-write-req -a 0x003d -n 0502042A02FA00
sleep 0.25

# beep(cH, 125)
gatttool -i hci0 -b A0:E6:F8:1E:58:57 --char-write-req -a 0x003d -n 0502040B027D00
sleep 0.125

# beep(b, 125)
gatttool -i hci0 -b A0:E6:F8:1E:58:57 --char-write-req -a 0x003d -n 050204D2017D00
sleep 0.125

# beep(cH, 250)
gatttool -i hci0 -b A0:E6:F8:1E:58:57 --char-write-req -a 0x003d -n 0502040B02FA00
sleep 0.25
      
# delay(250)
sleep 0.25

# beep(f, 125)
gatttool -i hci0 -b A0:E6:F8:1E:58:57 --char-write-req -a 0x003d -n 0502045D017D00
sleep 0.125

# beep(gS, 500)
gatttool -i hci0 -b A0:E6:F8:1E:58:57 --char-write-req -a 0x003d -n 0502049F01F401
sleep 0.5

# beep(f, 375) 
gatttool -i hci0 -b A0:E6:F8:1E:58:57 --char-write-req -a 0x003d -n 0502045D017701
sleep 0.375

# beep(a, 125)
gatttool -i hci0 -b A0:E6:F8:1E:58:57 --char-write-req -a 0x003d -n 050204B8017D00
sleep 0.125
  
# beep(cH, 500)
gatttool -i hci0 -b A0:E6:F8:1E:58:57 --char-write-req -a 0x003d -n 0502040B02F401
sleep 0.5

# beep(a, 375)
gatttool -i hci0 -b A0:E6:F8:1E:58:57 --char-write-req -a 0x003d -n 050204B8017701
sleep 0.375

# beep(cH, 125)
gatttool -i hci0 -b A0:E6:F8:1E:58:57 --char-write-req -a 0x003d -n 0502040B027D00
sleep 0.125

# beep(eH, 1000)
gatttool -i hci0 -b A0:E6:F8:1E:58:57 --char-write-req -a 0x003d -n 0502049302E803
sleep 1.0

# beep(aH, 500)   
gatttool -i hci0 -b A0:E6:F8:1E:58:57 --char-write-req -a 0x003d -n 0502047003F401
sleep 0.5

# beep(a, 350) 
gatttool -i hci0 -b A0:E6:F8:1E:58:57 --char-write-req -a 0x003d -n 050204B8015E01
sleep 0.35

# beep(a, 150)
gatttool -i hci0 -b A0:E6:F8:1E:58:57 --char-write-req -a 0x003d -n 050204B8019600
sleep 0.15

# beep(aH, 500)   
gatttool -i hci0 -b A0:E6:F8:1E:58:57 --char-write-req -a 0x003d -n 0502047003F401
sleep 0.5

# beep(gSH, 250)
gatttool -i hci0 -b A0:E6:F8:1E:58:57 --char-write-req -a 0x003d -n 0502043E03FA00
sleep 0.25

# beep(gH, 250)
gatttool -i hci0 -b A0:E6:F8:1E:58:57 --char-write-req -a 0x003d -n 0502041003FA00
sleep 0.25

# beep(fSH, 125)
gatttool -i hci0 -b A0:E6:F8:1E:58:57 --char-write-req -a 0x003d -n 050204E4027D00
sleep 0.125
    
# beep(fH, 125) 
gatttool -i hci0 -b A0:E6:F8:1E:58:57 --char-write-req -a 0x003d -n 050204BA027D00
sleep 0.125

# beep(fSH, 250)
gatttool -i hci0 -b A0:E6:F8:1E:58:57 --char-write-req -a 0x003d -n 050204E402FA00
sleep 0.25

# delay(250)
sleep 0.25

# beep(aS, 250)
gatttool -i hci0 -b A0:E6:F8:1E:58:57 --char-write-req -a 0x003d -n 050204C701FA00
sleep 0.25

# beep(dSH, 500)
gatttool -i hci0 -b A0:E6:F8:1E:58:57 --char-write-req -a 0x003d -n 0502046E02F401
sleep 0.5

# beep(dH, 250)  
gatttool -i hci0 -b A0:E6:F8:1E:58:57 --char-write-req -a 0x003d -n 0502044B02FA00
sleep 0.25

# beep(cSH, 250)  
gatttool -i hci0 -b A0:E6:F8:1E:58:57 --char-write-req -a 0x003d -n 0502042A02FA00
sleep 0.25

# beep(cH, 125)
gatttool -i hci0 -b A0:E6:F8:1E:58:57 --char-write-req -a 0x003d -n 0502040B027D00
sleep 0.125

# beep(b, 125)
gatttool -i hci0 -b A0:E6:F8:1E:58:57 --char-write-req -a 0x003d -n 050204D2017D00
sleep 0.125

# beep(cH, 250)
gatttool -i hci0 -b A0:E6:F8:1E:58:57 --char-write-req -a 0x003d -n 0502040B02FA00
sleep 0.25

# delay(250)
sleep 0.25

# beep(f, 250)
gatttool -i hci0 -b A0:E6:F8:1E:58:57 --char-write-req -a 0x003d -n 0502045D01FA00
sleep 0.25

# beep(gS, 500)
gatttool -i hci0 -b A0:E6:F8:1E:58:57 --char-write-req -a 0x003d -n 0502049F01F401
sleep 0.5 
  
# beep(f, 375)
gatttool -i hci0 -b A0:E6:F8:1E:58:57 --char-write-req -a 0x003d -n 0502045D017701
sleep 0.375

# beep(cH, 125)
gatttool -i hci0 -b A0:E6:F8:1E:58:57 --char-write-req -a 0x003d -n 0502040B027D00
sleep 0.125
           
# beep(a, 500)
gatttool -i hci0 -b A0:E6:F8:1E:58:57 --char-write-req -a 0x003d -n 050204B801F401
sleep 0.5

# beep(f, 375)
gatttool -i hci0 -b A0:E6:F8:1E:58:57 --char-write-req -a 0x003d -n 0502045D017701
sleep 0.375

# beep(c, 125)
gatttool -i hci0 -b A0:E6:F8:1E:58:57 --char-write-req -a 0x003d -n 05020405017D00
sleep 0.125

# beep(a, 1000)
gatttool -i hci0 -b A0:E6:F8:1E:58:57 --char-write-req -a 0x003d -n 050204B801E803
sleep 1.0