Sign up or log in to customize your list. Here's how it works: Anybody can ask a question The best answers are voted up and rise to the top I would like to build a remote controlled car. And if someone already has a good solution for that I would be glad to try it. It's been a while since I had the time and material to build some LEGO creations. And now I am willing to start anew. Last time I toyed with LEGO there were electric engines and such, but all I had was remote controlled with a cable and the functions were very basic. I am looking for a more advanced and wireless solution. I am aware of the Power Functions. But I have no experience with these. Would these be a good start? What are the other options? Edit: Mindstorms as suggested in a few answers could be the solution, but I am not sure it will be practical yet... It seems there was an official line of LEGO RC cars at some point. I was thinking about something more like it. Although I'd like to avoid cutting and gluing 3rd party components I don't mind hacking a few parts together to get something really cool.
As suggested by @pcantin there are adapters I could buy to interface LEGO with 3rd party engines etc... I will look into it. But I would appreciate some better pointers in this regard. Edit I am already aware of the Power Functions IR remote control It's a good solution to start with (now), but I was looking for something more advanced. I have never heard of Arduino before, but as a developper I am absolutely thrilled by this solution. I won't have the time to test it now. But it could become the answer I was looking for. technic remote-control power-functions mindstorms 3rd-party I use a Mindstorms NXT brick and an Android smartphone for my remote controlled tank. The downside is that the NXT motors are slower than the regular Power Functions motors, and connecting PF motors to the NXT brick requires additional components. Personally, I am satisfied with NXT motors and don't bother kludging PF motors. Personally I would go with Arduino (on the car) and an Android phone as the controller (via bluetooth).
There's plenty of reference on the web about mixing the two. The main problem is interfacing with non Lego parts (motors, PCB, ...). Luckily, you can find Lego adapter parts in many Robot/Electronic sites. For example at Pololu: Android bluetooth communication: There's the main page and the sample (I started from that one and modified it). You can also use the 'Sena Bterm' app to send and receive characters (no programming necessary but very basic). Arduino bluetooth communication: This is the most simple part. All you need is a bluetooth breakout board and connect it to the Arduino like so. Using the board is as simple as any normal Serial communication ex: int inByte = 0; if (Serial.available() > 0) This code reads the incoming bytes and write 'test1' or 'test2' in return. Hardware: this is the coolest part because you get to do what ever you want. I personal use a lot of Lego Technics and sometime modified them to interface with foreign parts. Search the web and you'll find cool Lego-compatible stuff like this servo joint, this servo bracket or this wheel.
LEGO have produced an IR Speed Remote Control unit as part of their current "Power Functions" range. Features 4 RC channels, 2 stop button and 2 direction control switches! Use the jog wheels to control your motor speed! You will also need the receivers as well. The MindStorms NXT controller can work over bluetooth: The 9398-1: 4x4 Crawler is an interesting candidate with the new servo motor. It comes in 2H2012. There are more pictures on TechnicBricks. I saw an official Lego remote control car at the Lego Store once and I should have gotten it that day because I haven't seen it again. That said, with Mindstorms and a bluetooth enabled phone it should be possible to build one one your own. Sign up or log in Sign up using Google Sign up using Email and Password Post as a guest By posting your answer, you agree to the privacy policy and terms of service. Not the answer you're looking for? Browse other questions tagged technic remote-control power-functions mindstorms 3rd-party or ask your own question.
In our house we love to play with remote controlled cars. But RC cars in the kid-budget area tend to break after a few hours of use. and we got some of the “motor” pieces that normally only come with some of the largest Lego Technic sets. And very quicky, a remote controlled car in Lego Technic was put together, and it actually gave the same play ability as a normal remote controlled car, plus the entire Lego universe. And it seems unbreakable – If something “breaks” – we put it back together again, or perhaps a new car is suddenly a reality. The center piece is the “88004 Servo motor”, a motor that gives a 180 degrees turn and can be controlled with any of the IR remotes from Lego. We had the IR Receiver (8884) from a Lego train system and we got the 8885 remote controller. A motor and a battery box is of cause needed, the standard 8293 motor set will do fine, however, if you want more power, the new L-motor or XL-motors are great for speed and power.
We use the L and XL motors that reason. Watch this small video for a demo of the car: Here are links to the three pieces needed – Total investment if you already have a motor set is $50 – Not bad for unlimited supply of different remote controlled cars.If you would like to appear to be from a different country - e.g. to change the displayed currencies - select a country from below.It has long been a dream of mine to build a remote controlled LEGO car. LEGO has many Technic cars in their program that use the Power Functions to remote control certain functions, such as opening doors or lifting an arm. Power Functions use infrared light for communication between the sender and the receiver. In the past, LEGO also had remote controlled cars that use radio frequencies, which is much better, since it does not require a line of sight and has a much further reach. Recently, LEGO released the 4×4 Crawler and it really triggered something inside of me. I ordered the set, but when it arrived I never put it together.
I started to build my own cars right away. I looked for inspiration on the internet and found many great off road cars, trial trucks and multi purpose car technology. In particular the work Pawel “Sariel” Kmiec. Check out his book “The Unofficial LEGO Technic Builder’s Guide” or visit his website. LPE Power also has some wonderful instructions on how to build real car technology with LEGO. Speed, torque, weight, balance, clearance and grip are the key factors when designing an off road car. Your choice of motors, gears, wheels, and chassis all influence these factors. Four wheel drive is a must for off road cars. Differentials are a big no-no due to the slip. A wheel detached from the ground would spin freely, while the wheel still on the ground will receive not torque at all. I also do not believe that a suspension system is necessary for a LEGO off road vehicle. There are no passengers that require comfort and the big tires already absorb enough energy. LEGO has many motors in their program.
The most recent Power Function Motors come in three sizes that vary in terms of rotation speed and torque. The higher the speed the lower the torque. You can find out about the exact characteristics in this web page. For the steering you might also consider using the new servo motor. You can change the speed/torque ration through the usage of gears. Sariel is offering an excellent tutorial on gears. More importantly, you can build gear boxes to shift gears. This enables you to have a lot of torque when you go uphill and more speed when you go down the hill. Again, Sariel is offering instructions for a heavy duty gear shift. I tried other compact gear boxes, such as smooth three gear box, but they all failed under a lot of torque. Here is my extension of the slfroden’s original design. I used a linear actuator to switch the gears remotely and you can now use two motors on it. I left out the neutral gear to make it more compact. It is a nice design, but not suitable for off road vehicles:
Next, I expanded Sariel’s original design since I did not want to move the motors around. Moreover, I wanted to attach two motors directly onto the gear box without the need of extra gears. You can use a linear actuator attached to another motor to shift the gears through a remote control. Here is a video of the gear box: So here is my super ambitious first model. It has two XL motors, a gear box that can be operated remotely, four wheel drive, lots of clearance. The battery pack is all the way in front, making it a good climber. I used the servo motor to steer the front wheels and the 8879 to remote control the servo. This was an complex design and in the end pretty useless. The steering was difficult to control. Most of all, it was slow. Turning the wheels from left to right took forever. Hitting the red stop button to bring the wheels back into the neutral position was often the fastest way. The gear shift also turned out to be problematic. Sometimes the gear was in a “in-between” state.
The only solution would have been to glue the tooth wheels onto the axis to prevent them from changing their position on the axis. Due to the lack of a suspension system, wheels did also occasionally lift from the ground, which resulted in a lack of grid. In conclusion, this is a far too complex design. There are numerous places where problems can occur. Back to the drawing board! I radically changed my approach. Instead of building a steering system and a propulsion system separately, I took the “all wheel drive” approach. It works similar to a continuous track, often found in tanks. Electrical cars also use the idea. In essence, you attach each wheel to a dedicated motor. My first design, however, ended being extremely wide: In the next design iteration I placed the motors along the main axis of the car. This was a much better climber since I could also place the battery pack right on top of the front axis: The main drawback with this design was the small clearance.
The car could not drive over obstacles easily. So, in the third design, I put the motors up and used the angled bars to bring up the chassis. This was an even better climber but the M motors are very difficult to mount. In the fourth iteration I used the L motors which gave me nice and compact car. It could easily get up slopes and drive over obstacles: But why stop at 4WD when you can go 6WD? My 6×6 ATV vehicle used six motors. Worked perfectly fine, but was slower than the 4WD. The battery can simply not provide enough juice to run more than four motors simultaneously. This six wheeler got pretty heavy and complex again, so I thought it was time for some minimalism. I tried to build a slightly geared down vehicle. The building instructions for this ultra light car are available and you may consider using the L motors instead to get more power. You could then use bigger wheels which does enable the car to drive upside down. Here is a video of the car driving around:
This was a lightweight and working model, but due to lack of suspension, wheels could still be lifted from the ground. It is desirable to have as many wheels on the ground as possible. Individually suspended wheels, such as in the super car, have a tendency to be fragile and pendular suspension systems are a better option. The 4×4 Crawler uses such a system. The same effect can be achieved by using a joint in the middle of the car that allows it to twist along is main axis. My final design iteration included a joint in the middle of the car that allowed it too twist. You can download the instructions as LXF file for LDD. Check out the model at Rebrickable. This design still did not have a good clearance, so I lifted the axis a little bit and got to my final design “RACE“: Each wheel is powered by one L motor. This design eliminates any loss of power due to tooth wheels. It is fast and at the same time it has enough torque to go up steep hills. The short wheel distance and the large wheels gives it the ability to climb over objects.
Here is the car, named “RACE”, from the bottom view. Here is a video of RACE in slow motion: I build a more robust and simpler version called RACE2 (how surprising). I added a roll over cage, bumpers in the front and the motors are now better attached to the chassis. Building instructions and more photos are available. After completing this RACE car, I had one week left to try out continuous tracks. The first thing I noticed was that the LEGO tracks are extremely smooth and have very little grip. They could hardly get up and obstacle or hill. My first attempt at improving the tank was to rise its front wheels: This design was still a failure, since the front had now a high level of attack, but still no grip at all. In an act of desperation I decided to “spike” my tracks by adding 3/4 Pins into it. With this small change, the tracks could bite into every little crack or edge. Finally it could get up anywhere, although I am pretty certain to ruin all the pins in the process.