This instructable will show you how to make the LEGO Galaxy squad set, Hive Crawler, motorized using LEGO Mindstorms (either NXT or EV3 should work). I call it dissection in the title because that is what it feels like I am doing. I (and maybe some of the readers of this instructable) will be ripping out sections of the underside, to squeeze in a LEGO motor.
This set has a really cool feature, that when you push the bug along a flat surface, all six legs move up and down to make it seem like it is an insect crawling on the ground. And it works really well. But I thought that I could somehow make a Mindstorms motor fit. This might work with some modifications for power functions, but unfortunately, I do not have any. After building this model in LDD (Lego Digital Designer) and playing with the spacing for a few days, I finally found a way that works.
Step 1: Download LDD
*Throughout this instructable, I will be putting some important information in the pictures. If you are new to instructables, if you click on a picture, and hover your mouse over an outline of a square, it will show a note that the author put in.
If you have this set and you want to make the modifications, I will upload an .IXF file (an LDD file), that will show you how to build most of the original model, and my modified one. In order to use this program, you need to, of course, download it: Download LDD Here.
You can download the .IXF file on this step too.
Step 2: Remotes
Also included in the file, are two remotes, each a different design, and both use a NXT brick (and EV3 with slight modification). I will include the programs for both. I will also explain how to set up the rubber bands in the pictures. I will explain what they do in the programing step. Sorry for the LDD grid in the pictures.
In the first picture, loop rubber band 1 over peg 1 and the Center peg, and loop rubber band 2 over peg 2 and the Center peg.
The Second and Third pictures are of the same remote, but different parts of it. So I will explain that part of the remote in that picture.
Second picture: Loop the rubber band across peg 1 and peg 2.
Third picture: There is actually nothing to do here. Just build it.
I will refer to these remotes in future steps as Remote 1 and Remote 2, in the order of explanation.
Step 3: The Bug
Unfortunately, I will not be showing step by step instructions due to the .IXF file, but I will be showing the bug itself from various points of the underside, as well as all the pieces you should have left over. I will also show an easy way to split the bug in half, so you don't have to take the whole thing apart. Most of the work will be in the back half of the bug, but the front is where the motor attaches.
Step 4: Working on the FRONT Half
Go through the LDD file and try to figure out how to modify the front half. You can split the bug in LDD if it would be helpful for you. Look through these pictures and read the notes I have inserted in them to see what the finished half would look like at different angles.
Do the same for the back half (next step); there will be more work to do there.
Step 5: Working on the BACK Half
Here is where most of the work is done. You should not need to add many pieces in, but you may find it helpful if you do in certain places. The pieces that you take out are not so you can add something, but it is just to make room for the motor that we attached in the front half.
Once you have completed both FRONT and Back halves, put them back together as seen in the previous images. You then want to put a Mindstorms wire (The longest mindstorms wire is 50cm) into the motor. Try to make the wire the longest one you have. If you want other wiring options (like no wires at all) go to the last step of this instructable.
Step 6: Pieces Removed
The pictures that show the removed pieces are split into two categories: Technic pieces, and bricks/plates. Keep these pieces in case you later decide to rebuild the original set. Keep in mind that some of the pieces (ones not shown in the picture) will be used in other places during the motorization process. If you are someone who build LEGO's a lot, and has bin(s) of LEGO, you should put the pieces in a Ziplock bag so you don't use the pieces for other creations.
Step 7: The Finished Product
Now you have a LEGO bug that does not look altered from the front. Unfortunately, you can see some changes from the back, and the "egg catapult"(another feature) will stop working.
Step 8: Programing
You can download the program here, but only if you have LEGO Mindstorms EV3 installed on your computer. If you do not have it, you can download it here: EV3 software.
Once you have it installed, open my program, and you will see a few 'tabs' on the top. The main program is simply called "bug" and is essentially the master program ('bug' is the program for REMOTE 2 ONLY). If you want to use REMOTE 1, it is in the tab titled 'mini remote'. Just download the correct one for the remote you have.
MAKE SURE YOU PLUG THE MOTOR INTO PORT C!It does not mater which remote you use!make sure it is in port C!
Step 9: How the Remotes Work
You are supposed to hold the remote with your left thumb on the lever. When you push the lever forwards, it pushes the touch sensor closest to you. This sensor, when activated, moves the robot forwards, and the reverse happens when you pull the lever back. because of the two rubber bands that are linked to the lever, it will always come back to the center position (pressing nothing), no mater which way you push the lever.
There are three parts to this remote: The dial, the the lever, and the bottom touch sensor. I will explain what each does.
just rotate it forwards to move forwards, move it farther to go faster. There is a number that will appear on your screen. This is just an indicator to show you where the dial is at. You will need to turn it to zero to make it stop. Turn backwards to go backwards; The screen will show negative numbers.
When you press on the panel closest to you, it will press a lever which will press a touch sensor, which will also make it go (at full speed). This is if you do not want to deal with the rotation of the dial.
The Bottom button:
You can hold the remote as you usually would, and still be able to press this with the lower palm of your left hand. This will make the bug to come to a complete stop. It is very useful if you are using the dial.
Step 10: If You Can...
If you can/know how, you can go into the settings of the Brain of your mindstorms and make it wireless! I know you can do this with EV3, but I am not sure about NXT. If you do this, you will get rid of the distance barrier and will no longer need to be connected to the brick with a 50 cm wire. I HIGHLY recommend you do this if you can.
Step 11: Conclusion
Here is a video of the bug moving.
So now we have turned our lego Hive Crawler set into a motorized bug. Now go on and freak out your family and friends with it. Just kidding. Maybe. Sort of.
If you have any questions about this feel free to post it in the comments, and if you liked this, let me know in the comments.