I’m a fan of Lego robotics. I’ve written over half a dozen books on the Lego Mindstorms NXT robotic system, and tinkering and prototyping with the NXT just never gets old. (And there’s a NEW system coming out later this year — EV3 — that I cannot wait to get my hands on!) The same goes for the Arduino microcontroller. Once I started diving deeper into the electronics hobby and discovered the Arduino, all sorts of projects started developing in my head. Unfortunately, the NXT hobby and the Arduino hobby have been kept in their own separate sandboxes in my office. It’s not that they can’t get along… it’s just that I haven’t really spent much time investigating how best to combine these two hobbies.This article has been reproduced in a new format and may be missing content or contain faulty links. to report an issue. Thankfully, the investigation has been done by someone else, leaving me more time to play and experiment. GeekDad’s very own John Baicthal has joined Matthew Beckler and Adam Wolf (co-founders of Wayne and Layne) to release .
Just like other Make: books, it’s a high-quality, full-color book that lays flat and looks great. It’s part of the Learn by Discovery series, and it contains a straightforward introduction to combining NXT robotics with the Arduino using a mix of projects (six in all) and easy-to-understand discussions on a variety of topics that include the basics of electronics, a breakdown of the NXT and Arduino systems, and advanced building and programming techniques. The book doesn’t dawdle… Chapter 1 starts you right up with the Drawbot project. It’s a mix of Lego parts that include some beams and motors as well as an Arduino Uno and a special shield (used to allow the Arduino to use the NXT set’s motors and sensors). All projects start out with a simple description of the device and then provide a detailed Parts List so you’ll know exactly what you need to assemble in terms of electronics components and other miscellaneous parts (such as a clothespin to hold a marker that the Drawbot will use to draw random sketches on a piece of paper).
Numerous sidebars provide additional information on topics that are introduced in the various chapters. For example, in Chapter 1 there’s a brief sidebar that talks about the special Bricktronics shield that is needed for most of the projects in the book. This shield is purchased from Wayne and Layne and soldered together to create the bridge between NXT motors and sensors and the Arduino microcontroller. Once you’ve got the Bricktronics shield assembled, merging an Arduino with the NXT components is possible. In addition to the electronics Parts List, you’ll also find the Lego Elements List — this is a lettered list that matches up to a visual figure for each project, making it easier to find the Lego pieces you’ll be using. I’m including an example here so you can see just how well the book documents all the parts you’ll need from the NXT set. I don’t have an estimate on the costs for all the various components used in the book; the Bricktronics shield is $35.00 unassembled, but most components are going to be between $0.25 and $10.00 (my estimate).
It does appear that Wayne and Layne have packaged up all the components you’ll need to build the Drawbot, so there may be plans to source all the components for the other projects in the book and sell them in pre-packaged kits as well. Learning electronics is not the cheapest hobby, so I just want you to be warned and approach these projects knowing you’ll be buying some non-Lego parts that don’t come in the NXT kit.Jump to: navigation, search The BeagleBone Motor Cape with NXT Connectors gives BeagleBone boards the ability to drive different types of motors. This cape features TI motor driver DRV8833 that can drive up to eight DC brush motors at 500mA per motor. This Motor Cape is populated with NXT connectors to interface with Lego Mindstorm NXT devices. Note: The BeagleBone Motor Cape with NXT Connectors requires to be powered via 5V barrel jack. Powering via BeagleBone's USB port will not work properly. Note: The barrel power jack on the BeagleBone Motor Cape with NXT Connectors is rated at 2.5A.
Refer to the schematic for option to provide more current. Note: The BeagleBone Motor Cape with NXT Connectors is provided with NO software support. 5V via expansion connector Up to 8 DC brush motors Two 46-position stackable connectors BeagleBone Motor w/ NXT Connectors Please visit Where To Buy for a list of distributors who carry BeagleBoardToys' capes. For more information about this cape, please visit BeagleBoardToys.info To go back to the cape list, please click BeagleBone Capes Posts: 2 Joined: Thu Dec 22, 2011 6:51 pm How can i detect a stalled motor? Posts: 305 Joined: Wed Dec 05, 2007 1:27 am Location: New Mexico, USA Re: How can i detect a stalled motor?I did try it. but it doesn t work correct.Here is an example code:Code: Select allboolean stalled=false;NXTRegulatedMotor m = new NXTRegulatedMotor (MotorPort.A)m.setSpeed(400);m.forward();while (! stalled){ if(m.isStalled()){ m.stop(); }}When i block the Motor and release it the motor continues rotating forward.
The function isStalled always returns false. Try slowing down the motor to see how the behavior changes. It is going to work as hard as it can to rotate at the speed you specify and higher speeds=higher power=resistance is overcome=stalls are less likely for a given resistance.Also, you may want to put a delay in the loop as it is checking isStalled() as fast as possible which is a bad design because the CPU is being hogged by your loopCode: Select allwhile (!m.isStalled()){ Delay.msDelay(100);} Posts: 5655 Joined: Fri Sep 28, 2007 2:06 pm Hi,Detecting a stalled motor is actually a tricky thing to do. The default settings in the regulated motor class are pretty conservative and will take a short while before the motor is considered stalled. This will also mean that considerable power can be applied in an attempt to keep the motor moving. It is possible to adjust the parameters controlling the stall detection logic using the setStallThreshold methodhttp://lejos.sourceforge.net/nxt/nxj/api/lejos/nxt/NXTRegulatedMotor.html#setStallThreshold(int,%20int)But adjusting these values may result in a stall being detected when the motor has not in fact hit the limit, you will need to experiment with the settings to find ones that work for you.