MajorAlvega

Oh yes, it derails a lot :) (but never stucks, at least until I write this, but Murphy is always watching) Sucess rate is 35- 50% I used a worm gear between the motor and the Technic turntable to reduce backlash but also used wheels with tires to sustain the track... the wheels slip a bit and also let the track go up and down like a fishing rod. The sensor and some backward-and-forward at the end of each half-turn do compensate the slipping part but only half the times (I mean one half turn its almosts always perfect aligned, the other half turn fails a lot). Since I use road baseplates I think that replacing the wheels with boat studs (2654) will reduce some backlash. And adding a gear between the motor and the worm gear will increase precision of the turntable. But I'm pretty sure that I'll need a better sensor, perhaps a second touch sensor or a light barrier instead. Next weeks will tell, now I'm trying a decoupling technic. Exactly the same with me :D I ordered a used Duplo Train and made it work with a a PF IR (and also an SBrick, but my kids are to young to have a phone) and they got crazy so i started playing with PF motor trains and my wife got crazy, wanted a train in our Nativity Scene. Now all family want to play with «my train» and no one cares for Duplo trains anymore :(

Yes, it looks like so :) If moderators decide to move it, OK for me. But since I don't consider myself a train guy and most of this setup is really Mindstorms-related I thought it should belong here.

You can use the PiFace Digital extension for the Pi, it has 8 outputs and 8 inputs. The outputs are open-colector darlingtons, can drive most LEGO motors but just one direction. Two of those outputs are also relays so you can drive one LEGO motor both-directions with 2 outputs. Or you can add H-bridge modules to drive up to 4 motors (each H-bridge uses two outputs). The inputs can be connected to LEGO 9v touch sensors or PF switches. 4 of the inputs are also connected to tactile buttons. You can use software interrupts or just carefull timings as an alternative to the lack of PWM in the Pi. Here a configuration I used one year ago, using just one motor (but could use 2, it's a dual H-bridge board). I like the PiFace Digital because it isn't intended for any particular purpose but there are also extensions intended for motor control with H-bridges included like the RasPi Robot Board v2 by MonkMakes.

Hello. This is about trains but I think it's more appropriate to post it here under Mindstorms theme. My LUG (PLUG, from Portugal) train fellows have been developing their own modular standard (MFL) for our exihibitions. Since it defines a 6-brick height above the table surface there is plenty of space under the tracks to hide motors, gears and gadgets. That idea attracted me so I decided to try MFL. First I rebuilt a motorized track switch I was already using with WeDO and then decided to also try a turntable and then... well, you know :) At this stage, this is my setup: - a Mindstorms EV3 running ev3dev (Debian linux) to control everything - a wi-fi USB dongle (not essential but allows me to use my laptop as a console, much more easier this way) - a bluetooth 4.0 USB dongle to control the SBrick-based trains - an EV3 ultrasonic sensor to sense when the train reaches the middle of the turntable - an EV3 touch sensor to sense each time the turntable completes a 180º turn - two Power Functions lights (with a NXT-9V adapter) to signal the movement of the turntable and the control of the train - one USB RFID reader to sense/identify the trains - one LEGO WeDO to control the two track switches (one Power Functions M motor under each) Each train has: - a SBrick (will try IR later) - a RFID tag The train is brought to the RFID sensor where the EV3 recognizes the train (green lights start blinking) and tries to establish a bluetooth BLE connection to the SBrick (green lights keep ON). Then the EV3 takes control and sends the trains to the turntable, using the ultrasonic sensor to prevent collision against the end of the turntable. When the turntable starts turning, the red lights blink (and a claxon sound plays, but its not used in the video). There is also a touch sensor under the end of the track that senses when the turntable completes each 180º turn. Then the EV3 sends the train back to the starting point, using the RFID sensor to detect the train. The bluetooth connection is dropped and now the train is available for manual control. The EV3 is ready for another train. For a near future I plan to give good use to the track switches (only one is motorized but the second will follow soon). I also want to try a method I saw here at Eurobricks to separate the train engine from the wagons. This way the train engine could drop the wagons, revert direction at the turntable, move along the left path and pick the wagons again. To be honest, the turntable still needs some adjustments - sucess rate is ~1/3, sometimes the train slips when moving in, sometimes when moving out.

Muito, muito bom! Parabéns! Very, very good! Congratulations!

Hi. I use WeDO mainly for two purposes: - control LEGO motors from my computer at the beginning of my projects (I find it easier to use the PC than the Mindstorms) - use more than 4 motors with my EV3 Here you can see my first experiments with an automatic train turntable: I used WeDo to control it from my PC: After a while, I switched to the EV3 (running ev3dev) and used the very smae scripts. Then I dropped the WeDo and now I use a EV3 motor but will use the WeDo later to control 2 track swicthes like this one:

The WeDo distance sensor is a IR emitter/receiver (see this post at http://www.legoengineering.com/). So the "line" just need to reflect/absorb more IR light than the "floor" to change the "distance" readings. Of course, you need to ensure that real distance between the sensor and the floor never changes.

The 8887 "LEGO® Power Functions Transformer/Charger 10VDC" is also the "LEGO® Power Functions Transformer/Charger 10VDC". It seems not available at UK site now but for my Country (Portugal) it is available (€24.95) so it's probably a momentary situation. You may also use any AC/DC adapter with output between 10V to 12V and at least 700 mA. There are some "universal" adapters with several inter-changeable plugs, I've been using one of those (1A, 12V) after I found that it has the right plug, like the one at the bottom in this image:

Sariel, you've been doing a great and admirable work. Two years ago, when I returned form my dark age, I got excited with all the great things one can do with Technic and I found some great books at No Starch Press. I bought Isogawa's Idea Books and your Unofficial LEGO Technic Builders Guide. And it was great to see a digital version option so I bought both, I still carry those PDF's with me on my laptop wherever I go and my older kid enjoys to see the paper version. I'm a computer guy in a country where everybody considers natural to use pirated software and download music and movies, etc. I started using Linux because I couldn't afford all the software I needed and I didn't want to be a pirate myself. I understand your pain. But please, if possible, keep releasing digital versions of your work. I'll keep buying it. There will always be pirates and most of them would never buy anything at all by nature (not a great excuse, I know).

If you consider the 9V PP3 battery box you can also consider a custom PP3 -> PF adapter and reclaim the space of the box and eventually other adapters. There are people selling it online but you can do it pretty easy.

Something like this? I'm using just one 3.7V LiPo but you can use two in serial and get 7.4V/400 mAh. You can make it even smaller, I have two 90 mAh LiPo from hobby drones, each one is about the size of the PF plug. The problem is how to recharge. If you use just one, you can cut a PF cable and solder your LiPo original plug to it. But if you use two in serial (a 2-cell battery) you need the common point (not just the - and +) because 2-cell chargers need it to «balance» the charge so both cells are charged equally - you could leave a third wire «hang loose» with some kind of plug at the end.

If you just want to program your spybotics, you can also use a RIS USB Tower so if you already have one you don't need to buy this cable. It is also possible to use a RCX to talk with the Spybotics using VLL.

Original EV3 firmware doesn't support the Edimax. In fact it doesn't support almost every Wifi dongle in the world other than Netgear N150 (WNA1100). But you can upgrade the firmware of the EV3 to include the drivers for the Edimax. I never tried it since I only use ev3dev (main reason: it supports allmost everything I can think of). If you don't want to try this, you need to get a Wifi dongle with the same chipset of the Netgear N150 (an Atheros AR9271, linux driver ath9k_htc). And even so it might not work if it needs a firmware different of the Netgear (some companies don't share their devices firmwares to the open source community so even if the llinux kernel supports the driver it can do nothing without the micro firmware that the driver needs). See this wiki about the Atheros AR9271, it lists some devices that uses it, including the TP-LINK TL-WN722N (almost the same model number of the TP-LINK you show above). Good luck!

You can also use isopropyl alcohol, it's used to clean electronic components [not etanol nor metanol!]. It dissolves in water and later evaporates so if you sink your receiver/motor in a bowl of it, most of the water will mix with it and flow outside. (sorry for bad english but I think you got the idea). It's also used in hobby models to remove acrylic paints but I don't think that's a problem for you. It does not affect ABS plastic.

Clean the receivers it with a towel and put inside a bag of rice for some days. The rice absorbs humidity, worked with my Android after 20 minutes at the bottom of the swimming pool. If possible, open the receivers cases.

According to LEGO, bright sun light can interfere. And according to this comment, fluorescent lamps to.

I don't want to sound pretentious as I have no experience with LEGO trains but I also think you can do a double loop or at least something more complex than just a single oval loop. This month started working with RFID and EV3 (Mindstorms) and decided to try it with my own «trains» [also started to read old eurobricks' train topics, lots of good info]. Space is also a problem so I used some flex tracks as it allows slightly narrower turns. My setup fits in 1.20m x 0.75m (almost 4 ft x 2.5 ft) and there is still some space remaining: Not great trains, I don't pretend to replicate real world models, just automate one or two mini/micro trains. Have two trains powered by an old 9V micro motor, quite slow but good for first programming steps. Also tried PF train motors, to much speed for such a small layout [and also for RFID detection] so I'm using only 50~60% power and they run for at least half an hour without incidents.

brackets media brackets link brackets /media brackets

I think your best chance is asking directly at social.sbrick.com 'technical questions', Tamás usually answers at same day. I think that present version of SBrick firmware doesn't offer this functionality. We are expecting (at least I am) a new version that offers internal temperature and voltage readings and some other functions. I think it's not possible to read current to detect stalled motor condition but it might be possible to infer from temperature, not sure if quick enough to prevent damage. And then you need client (SBrick App or 3rd party) support for it.

Resistor give some additional protection IF you change your power supply. 2 AA = just 2.6V, you are using rechargeable batteries or you are using non-fresh or cheap alkaline batteries? With 2 AA good alkaline batteries you should get 3.0~3.2 Volt. Still less than those Uf=3.3V but pretty close. LEDs are cheap, you may try. But resistors are also very cheap :)

I had. The PF servo doesn't have feedback. And if it had, the SBrick has no external input (at least not the actual version... there is some discussion about future features).

Yes, I'm also more interested in the automation/controll aspect. But for those who wanted to know if it's possible to drive 9V RC motors at full power (something that the PF IR can't do) these are good news. And your solution is quite good for a table project or an heavy tracked crane but as it would demand a second battery and an additional motor doesn't sound so appealing for not so big but still mobile models.

For those interested in using SBrick with HEAVY loads or FAST motors: I could reach 3.1 A in one port (the advertised limit is 3.0A). Then the internal drivers enter in protection mode and start clipping power.

You need something with the typical 9-pin plug that fits in the IT Tower plug. I've used the original cord, both ends are female and don't have those fasteners at both sides that wouldn't allow to insert it. You can get one from less than $2 at bricklink, http://www.bricklink.com/search.asp?itemID=8860&colorID=9 Everybody say that is not possible because there are no x64 version of the drivers. The workaround is the same: get a serial version of the tower, eventually also a USB adapter.

Well, I bring good news and bad news... The good news: 1. I got RIS 2.0 working with Wine (installs fine but when run I got a problem with it demanding 16 bpp, not quite sure how I solved it). 2. I got RIS 2.0 working with Wine AND LEGO IR Tower COM version with a USB-COM adapter The bad news: 3. I can't find a way to use RIS 2.0 with Wine and LEGO IR Tower USB version. Sorry. For others that might get here, here's how to use the COM version IR Tower with a USB COM adapter in Ubuntu: My adapter is recognized by Ubuntu as a "pl2303 converter" with handler /dev/ttyUSB0 I give it full access: sudo chmod 777 /dev/ttyUSB0 Then create the symbolic link for Wine to see it as COM1: cd ~/.wine/dosdevices ln -s /dev/ttyUSB0 com1 Then run RIS 2.0 with RCX already on. At 'Settings' RIS finds the tower at COM1, but I couldn't run or download programs so I choose "Download Firmware", it suceeded (but from RIS side never ended, had to restart it some minutes AFTER the RCX beeped). After that everything fine, RIS recognize RCX with firmware 2.0 and even shows battery level, and I can now run my own programs and download to RCX: