I'd like to find a way to make my Raspberry Pi control some Lego motors, and as a bonus I'd like to make use of one or more optical sensors. Normally, Lego robotics make use of the Mindstorms "brick" controller - this appears to be expensive and mostly redundant if you have a Raspberry Pi to issue commands. The Mindstorms controller is a processor and a motor-controller which can run without connection to a PC but lacks Ethernet and many features of modern computers. Is there any alternative platform that will allow me to control and receive data from Lego creations? FYI, this is for a simple bug alerting machine. The device will monitor the status of a Jenkins test framework and perform an action depending on the number of unit-test cases which are failing. The raspberry pi will poll a web-page which contains some easily parsed XML. If the number of bugs > 0, then we'd like to to make the Raspberry Pi start driving the machine. The standard Lego Mindstorms sensors are analogue (i.e. a voltage between 0-5?
V), or digital (I²C or RS-485) (source). I don't think the Raspberry Pi has a broken out pin in the GPIO for an ADC (analogue to digital converter), so we can't interface with analogue sensors (without an extra microcontroller). The Raspberry Pi does have two pins in the GPIO for I²C, which means that if you connect GND, +V, SDA and SCL to your sensors, you should be able to use an I²C library to talk to them. There's a driver here - if you follow the instructions you should be able to send and receive I²C signals as easily as this (talking to an TI TMP102): raspberrypi bootc # echo tmp102 0x48 > /sys/class/i2c-adapter/i2c-0/new_device raspberrypi bootc # sensors temp1: +21.6°C (high = +160.0°C, hyst = +150.0°C) There are a few articles on how to connect sensors and motors on this page, such as connecting a Mindstorm brick controller to an external microcontroller: There is BrickPi+ helps you connect LEGO sensors and motors to the Raspberry Pi and replaces the MINDSTORMS Brick.
Mindstorms is the only totally LEGO way of controlling more LEGO. The current NXT 2.0 is quite expensive, but you could pick up an older RCX kit (that is just an example) for something like 1/3 price of the NXT 2.0 on the web. Otherwise, you're going to have to look to a different motor/sensor kit that you might be able to attach to LEGO. These aren't exactly easy to find, and can be quite expensive; it might be worth trying to find someone who knows more about them if you go down this route. to get a snapshot of the market. (I discovered it a month or two ago. It's a great place to find info on the current market value of LEGO sets on ebay.) There is an alternative to all this, connect the NXT sensors and motors to the NXT control unit and then pair it via Bluetooth with the Pi, you can then send commands direct to the NXT to control it's motors and read it's sensors. check out the Mindstorms bluetooth developer kit, this allows the NXT to be completely wireless !!!!!
Browse other questions tagged gpio peripherals sensor or ask your own question.You will also need power, we recommend one of these:6-AA Battery Holder,Rechargeable battery Pack If you’re familiar with Lego Mindstorms, then you are probably aware of all the cool projects that you can make and the educational value of such an easy-to-use robotics platform. The BrickPi is a RasbperryPi add-on that lets you control Lego Mindstorm parts. The BrickPi stacks on top of the Raspberry Pi and accepts Lego Mindstorms motors and sensors. BrickPi on top of a Raspberry Pi The BrickPi allows you to control Mindstorms parts using any number of languages including C, Python, and Scratch. Covered in This Tutorial In this tutorial, we will cover how to get started with the BrickPi. We will show you how to connect the BrickPi to a Raspberry Pi, attach Legos, connect motors/sensors, and write a simple Python script to control the motors/sensors. Monitor of some sort HDMI Cable or Composite cable
Wall Adapter Power Supply - 9VDC DC Barrel Jack Adapter - Female Lego Mindstorms Servo Motor Lego Mindstroms Touch Sensor NOTE: The servo motor and touch sensor can also be found within the Lego Mindstorms NXT set. IMPORTANT: You need to use Dexter Industries' custom Raspbian build to get the BrickPi to work. Download Dexter Industries' Raspbian build 7-Zip to unzip the .rar Raspbian image Flash the SD Card Insert the SD Card into your computer Unzip Dexter Industries' Raspbian build (use 7-Zip if the image is in .rar form) Run Win32DiskImager with administrative privileges Select the unzipped Dexter Industries' Raspbian build as the Image File Select the location of the SD Card Don’t forget to Run as Administrator! You will need to build the hardware around the BrickPi in order to connect it to the Raspberry Pi and Legos. 1) Unpack the BrickPi hardware and remove the protective paper from the case. 2) Screw the two small standoffs into the holes in the bottom piece of acrylic.
3) Screw a Raspberry Pi onto the two bottom standoffs. 4) Screw the four long standoffs into corner slots of the bottom piece of acrylic. 5) Attach the BrickPi to the Raspberry Pi by mating the BrickPi’s header to the Raspberry Pi’s GPIO header.Now is a good time to label the motor and sensor ports on the BrickPi. I recommend S1, S2, and so on for the sensor ports and MA, MB, and so on for the motor ports. 7) Attach the top piece of acrylic to the four posts using the remaining screws. 8) Insert the SD card. Lego beams can be attached to the top and bottom pieces of acrylic in order to secure the BrickPi and Raspberry Pi to your Lego creation. Attach Lego pegs to the holes in the acrylic Attach Lego beams to the pegs Any of the Lego Mindstorms sensors can be attached to the ports labeled with an “S” followed by a number. You will need to remember the port number that you plugged your sensor into. Motors can be attached to the ports labeled with an “M” followed by a letter.
For this example, connect a single touch sensor to S1 and a single servo motor to MA. Similar to the setting up the Raspberry Pi tutorial, we need to connect a keyboard, mouse, and monitor. Plug a keyboard and mouse into the USB ports, and connect a monitor using an HDMI cable. Dexter Industries recommends a few different ways to provide power to your Lego robot. However, we will do things differently. In order to get unlimited run time and the ability to power a couple of motors, we will hack a wall power supply to attach to the BrickPi. 1) Cut the 9V battery connector off of the 9V Snap Connector and strip the ends. 2) Attach the red wire to the positive (+) and the black wire to the negative (-) screw terminals of the DC Barrel Jack Adapter. 3) Plug the connector into the BrickPi. 4) Plug the 9V wall adapter into the other end of the DC Barrel Jack Adapter. 5) IMPORTANT: Make sure your monitor is connected to the Raspberry Pi and turned on!
6) Plug the wall adapter power supply into a wall outlet. WARNING: The large power regulator (TO-220 Package) gets hot! Be careful when plugging or unplugging the power adapter. 7) Your Raspberry Pi should come to life! Configure the Raspberry Pi Once the Raspberry Pi has booted, you should be presented with the Dexter Industries desktop. If you are ever asked for a username or password, the defaults are: If you would like to configure the Raspberry Pi, open up a terminal: and enter the following command: You will be presented with the Raspberry Pi configuration screen. It is recommended that you expand the filesystem. Have a look at the other options (descriptions for the various options can be found here). Open a terminal (if you do not already have one open) and create a new file for our motor and sensor test. Open that file with Leadpad (Raspbian’s default text editor). Enter the following code into the text editor: from BrickPi import *