Step 2: The mechanical part

In the circuit, i left two 3mm holes at the back, so anyone can hook up it's own mechanical part.
I made mine from a 1mm thick brass plate, in the photos you can see how i cut and bent it. This structure can hold the mini motors and the wheels together and it makes a pretty decent rpm reducer. Then i threaded the holes so i can bolt this structure to the PCB without nuts.
The mini ball roller is used at the front of the robot as an all direction wheel, you can just solder a 5mm LED in that part, it has more friction, but it should work.

With this mechanical design, there are a few problems, the robot turns too fast the front part when there's a speed change in a motor, resulting in a instable direction, without changing the design, the only solution is making the robot slower, that can be done lowering the gain with the pot. But i realized that a better solution would be to made a different robot design, with the wheels in the same part as the  sensors, so the feedback would be much better. But for my first robot, this is OK.
What's the song in the video?
<p>The song is from the game &quot;icebreaker&quot;</p>
<p>I've been wanting to make this for a while and when my teacher said he wanted to do robotics with us I mentioned this and he asked me to prototype it but I can't find where to get the wheels or the roller, if anyone has the links can they please send them? It would be a great help, thanks - Luke</p>
The rollers or wheels are just rubber pieces from a printer/cassette that i had lying around.<br>I bought the micro motors from ebay<br>http://www.ebay.com/itm/Load-3-7V-30000RPM-Micro-VDC-Motor-6mm-Diameter-12mm-Length-Model-CL0612-/200911920772?pt=LH_DefaultDomain_0&amp;hash=item2ec7489e84
<p>Thanks for the help, one more question, where did you get the roller ball?</p>
<p>I made it from a brass stand-off screw, a steel ball and a spring.</p>
<p>can you make it on breadboard?</p>
<p>This is beautiful! Well done : )</p>
<p>Where did you get that mini ball roller?</p>
<p>you can take it easily from ball roller pens i think</p>
Hi Great Work :)
<p>the materials can pass me</p>
<p>Hi, great instructable!!!</p><p>I have one question: does it follow crossed lines, I mean, when there is a line crossing another line, does it stops or continues?</p>
<p>It does, but when it goes slow, it stops at them. </p>
<p>I built several servos from lm339 chips. I had trouble with the lm339 because it will short when the battery goes low. Both differentiators turn on when the battery goes low. The servos work just like cox sanwa servos. zzzz zzzz 1993. What does the 602 do when the battery goes low.?</p>
<p>I don't know what happens, I've chosen the MCP602SN because it's a rail-to-rail op-amp, and it works with low battery voltages. Yours should also work...</p>
could u use perf board because i cant print the circut
<p>Yes, you can sacrifice aesthetics and do it with a perfboard. It should work.</p><p>But making your own PCBs is not that hard, i make mine since i was 12 y/o and it's pretty easy, <a href="http://www.instructables.com/id/PCB-making-guide/" rel="nofollow">here's my instructable guide</a> about making PCBs, see how simple it is, and how good the PCBs can be made.</p>
<p>hey, i wanna buy one unity from you, you can sell?</p>
<p>Yeah, i can sell you the one in the instructable.</p>
<p>Awesome little robot and very good big descrition. Well done, I mean the robot AND the instructable. It was mentioned before, slowing down the motor wuld make a better choice.</p>
<p>Yeah, if it could go slower, it would follow much more complex lines. But the smaller the motor is, the faster it goes.</p>
<p> To address the instability, would it work better if instead of speeding up the side which leaves the line, you slowed the other side down? (This is completely off the top of my head with no means of testing it myself right now, but it seems an obvious question to me: if I'm wrong or you've already tried that and it didn't work, sorry to waste your time ;-)</p>
<p>It does both things; drive slower on the dark side, and faster on the bright one.</p>
<p>What are the chances of making this wired rather than PCB'd if one didn't care if the bot got bigger? Did the schematic get posted?</p>
<p>You&iexcl;ll probably prefer to use trough hole components. And as i said, the schematics are already posted as photos.</p>
<p>Would you happen to have some schematics of the circuits. I cannot open SCH files.</p>
<p>I've posted the schematics as JPG files (just the diagrams images in the instructable)</p>
<p>Could you please publish your schematic as a pdf, png or jpg?</p>
<p>There's a screenshot of the two circuit diagrams. One for the robot, and the one for a charger.</p>
<p>Fellow imgurian?</p>
<p>Good design and look. Nice thing is its without programming. I will also try it.</p><p>BTW what background music you have played in video. Its is also good to listen.</p>
<p>The music is from the nitrome game ''icebreaker''. They make awsome songs.</p>
<p>and i said something it recalls this music!!!</p>
<p>I agree , non micro-controlled projects are a rarity . Since a micro can replace many components it is first choice but we loose a bit of the art. </p>
<p>AWESOME! I forgot I had two unused &quot;super micro geared motors&quot;, I can finally put them in use :D They are so small even the Arduino's DIP chip is wider than the two geared motors combined :)</p>
<p>Two mini geared motors would make the perfect robot, with mine, the only problem is the speed, it's too fast.</p><p>If you use those motors, the same circuit could work awsome, following even sharper lines.</p><p>If you make a robot, please, i would like to see it!</p>
<p>guys if u have time visit:</p><p><a href="http://goo.gl/VML8lw" rel="nofollow">http://goo.gl/VML8lw</a></p><p>u'll be doing me a favour................</p>
<p>Who needs a bananna when you have that cute little guy!</p>
<p>Nice Job. But what about the ambient infrared light? How it reacts at outdoor sunny ambients or an amient with light bulbs?</p><p>I'd developed an anolog line follower too but i used an modulated IR led (with 555) and a passive filter at the foto-diode input.</p><p>If someone get interested here is the link: http://protocoloj.blogspot.com.br/2014/03/robo-seguidor-de-linha-analogico-v10.html</p>
<p>It is litle affected by external light due to the shielding, but it still goes a bit faster in sunny places.</p>
<p>great....Nice work</p><p>My homemade CNC</p><p><a href="http://adf.ly/e8gVq" rel="nofollow">http://adf.ly/e8gVq</a></p>
<p>such a beautiful design!</p>
<p>I just love how beautiful the circuit is designed from scratch. Projects without any kits, modules or ardruino are sadly pretty rare on instructables. So keep up the good work :D<br><br>If I find some time (what is unlikely but hey) I might give it a try to improve your design with an attiny. It'll be intresting :D</p>
<p>With better mechanics and mostly, with a processor, a great improvement can be made, but i did it all analog so no programming skills are needed, just soldering...</p><p>And i agree with your opinion, today, there's a lack of original circuits, most are based on arduino, raspberry-pi...</p>
<p>Awesome work, like always!</p><p>Line-followers are a lot of fun. Nice work!</p>

About This Instructable


393 favorites


Bio: I love electronics and all about DIY.
More by pinomelean: IN-12 nixie clock Li-ion battery charging Mini line tracer
Add instructable to: