S3NTRY: a LEGO Mindstorms Robot Sentry Turret

Introduction: S3NTRY: a LEGO Mindstorms Robot Sentry Turret

Welcome to my first Instructable.

These are the instructions for how to make my autonomous, not moving, sentry turret: S3NTRY.

The entire project can be made with 1 set of LEGO 31313 - EV3 retail.

NOTE: I noticed when putting all things together, that some pictures are fuzzier than I would like them to be. I apologize for this, my hands are a bit shaky. I hope you are nevertheless able to make thsi project.

Table of Contents:

1-The firing mechanism

2-The 'brains'

3-The program

4-Bonus: a frame I made

Backstory, read if interested:

I found a lot of projects to make on Instructables, and decided to make an account a long time ago. I've always wanted to make an Instructable, but never got to it. The contests where also a thing I wanted to join in, but never could, due to lack of tools, materials or time. Now, the First Author Contest triggered me, so I decided to make something.

I have had my Mindstorms EV3 since it came out, and never really made anything with it, besides the standard TRACK3R. I had worked with Mindstorms NXT once, 7 years ago and last week I had a conversation with someone who teaches on University, about how they use Mindstorms there. This intrigued me.

And so it started, I thought of a plan, I wanted to make a sentry turret, and set off to make it.

And this is the result, I hope you enjoy it.

This Instructable is submitted to the First Author project on 20 sep 2015

Step 1: The Firing Mechanism

This is the firing mechanism for EV3RSTORM, meaning I took this straight out of the factory instructions.

There is 1 addition, which is the L-shaped part, which I added next to the big gear, this is for attaching to the smart brick.I screwed up with adding that, So just follow the placement for that in the last 2 pics.

1- the finished firing mechanism
2- make these, the beams are 5 holes long
3- attach them like so
4- attach the big 36-teeth gear with a brown studded rod
5- make this
6- attach like so
7- gather these
8- assemble, note where the small, 2 long, red cross axles go
9- attach, I forgot to mention the light grey, 3 long, cross axle.
10- gather these
11- attach
12- make this, same as 2 and 3
13- attach, mostly the same as the other side
14- make these
15- attach
16- make these
17- assemble
18- attach
19- add 2 more of those red pieces, and push the grey axles through

20- Take off the first made side (the right side)
21- add the cornerpiece, it is 5 long and 3 wide. It is attached with one black peg, and the 2 black pegs at the bottom are for later attaching.

Step 2: The 'brains'

This is the main part. It is basically all you need. It consists of the EV3intelligent brick, to which I attached the firing mechanism and the 2 sensors.

1-4: Gather these and assemble as shown for the infrared sensor. Note that it's plugged in to port 1.
5-8: Gather these and assemble as shown for the light sensor. Note that it's plugged in to port 2.
9-13: Gather these and assemble as shown for the firing mechanism. Note that it's plugged in to port A.

Step 3: The Program

The attached file is the program I wrote for this design. In the picture you can see a rough overview.

The program is written with the infrared sensor in port 1, the light sensor in port 2, and the engine for the firing mechanism in port A.

You will need 'LEGO Mindstorms EV3 Home Edition' or a likewise computer program to open this.

Feel free to experiment with it.

Step 4: Bonus: Unmotorized Baseframe

This is the frame I used.
I won't go in detail about hwo to make this. It is more of an inspiration.
You could even add a motorized frame with wheels, so you can make it a bit more tank like.

I am sorry these pictures are a bit fuzzier, I added them last-minute

I used a hinging system to be able to make the frame stand on legs, instead of wheels. This, so it wouldn't roll away easily.

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    7 years ago

    You should add a video of the s3entry in action.


    Reply 7 years ago

    Good idea. I will add that.

    Mad laboratory
    Mad laboratory

    7 years ago

    Thx, I saved this so I can build this when I get my Lego mind storm set


    7 years ago on Introduction

    It's been a while since I've seen anything done with Mindstorm, we used them in junior secondary IT to learn the basics of program flow and the like. A nice throwback!