Let's Make Robots!

My 1st non-breadboard circuit :)

I know..a lot of you good folks could solder before you could walk and probably sleep with a soldering iron under your pillow (hope you remember to turn it off :), so here is this guy in his 30s bragging about his first circuit. Pathetic.

However soldering is a major challenge to me and actually the main reason I didn't get started with robotics years ago. It's just not easy for my unsteady hands. So I'm very happy to declare that I just finished my 1st working non-breadboard circuit. It's a motor+servo shield for my Arduino.

It has an L293D H-bridge chip, plugs into my Arduino and provides easy plug and play connectors for 2 DC motors, 2 servos and an external power source. Here are some photos (I know it ain't pretty but it's mine and it WORKS :)





PS: Now that the hardest part is over 1st robot coming up soon :)

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keep practicing, and learn to drill and solder.  get some scrap wood and learn how to drill, and get a small blank perf board to practice soldering
Like I said I don't even have a drill and I'm not getting one in the near future. But I will keep on practicing my soldering. As mentioned I'm planning a 2nd (more complicated) shield AND I wanna make a compass like the one OddBot posted here. Both ASAP. So there is no way around it :)

So.. you have to go get a drill...


That's such a bore..

But right now my robot budget is close to zero. The Argentinean customs charged me 100% (!!!) on my last shipment from DAGU which was quite a blow. So the drill is on my list of essential items that will have to wait. :( For now I'll have to start creating with what I've got and I'll only be buying small parts and tools I can't go wihout in any way (I need to buy some screewdrivers in different sizes for instance...only have 2).

The next time I start spending money I'll be getting a multimeter, a bluetooth module for my Ardiuno and a battery pack (right now I'm powering my setups using an old converted AT power supply).

Being a poor student sucks :(

PS: Any idea how to make holes in a protoboard WITHOUT a drill??

Lying around in my basement somewhere is a tiny hand drill that is actually intended for drilling holes in circuit boards. I can't even recall where I got the thing.

I know you are an a budget. Maybe you could find an old hand drill somewhere. Or if you can just get the drill bit you need, rig a wooden handle for it and turn by hand until you have a hole.

I could even imagine making a small bow (use a curved stick and a strong string) to make the drilling faster. It's an old technique for making a fire. You hold the bow horizontally, wrap a turn of the string around the vertical shaft of the drill handle you rigged, and then saw the bow back and forth. You'll be running the drill bit backward on the forward stroke,but that shouldn't matter much.

Sounds crazy, but it would be cheap and it might work. 

maybe you can heat up a pointy implement and melt it through?

I'm not entirely sure on what you're trying to do to the protoboard, and I don't have any experience with an arduino. sorry.

That's how I'm making parts for my robot: Cutting pieces from old CDs with a heated up hobby knife and then burning screew holes with a heated up paperclip :) It works pretty well. However a protoboard is somewhat different and I don't wanna destroy the one I have. But I guess I'll have to try it.

About the Aduino: In Arduino terminology a "shield" is a board that plugs into the Arduino as my board above. Between pin 7 and 8 there is a weird 2/3 pin sized spacing making it hard to make shields from standard protoboards. You can see the spacing here:


On my 1st board I simply bended the legs of the 2nd pin header to fit the Arduino, but I thought it would be a better solution to make holes in the edge of the board for the pin headers. So instead of making my 2nd shield like this:


... I'd turn the protoboard 90 degrees and use the holes in the edge for the pin headers that plug into Arduino. It would also leave 2 extra rows on the protoboard to work with.

Hope I made my intentions more clear :)

A small round file could do the trick. It`s only the tiniest of an offset in the pins.

Alternatively you can find a motor and fix a drill bit to the end with super glue. Seriously. I did it when I was a kid. It`s dodgy but works :)

Does anyone know of a good way to make holes in (the edges of) a protoboard like the one depicted? I currently don't have a drill so it has to be an alternative method?! Perhaps a screew or a heated up nail?!

1st off..I need to stabilize this shield since it's only attached to one side of the Arduino (the digital I/O's). There is a screew hole on the Arduino (near the rx/tx pins) that I could use to attach the shield. Only I need to make a matching hole in the shield...

2nd..This particular shield is for a simple 2 servo, 2 motor wheeled robot. I'm planning another larger shield for a 12-servo walking robot. It will have 12 easy servo plug ins + a shift register + 2 analog multiplexers + 12 shunt resistors for measuring the current draw of each servo in realtime like described here. And probably more stuff too :)

Anyway those of you familiar with Arduino will know that there is a weird spacing between the digital pin 7 and 8, making it quite a hassle to make your own shields. In this case I solved it by bending the pins that plug into the Arduino like this:


And while it did work I'm not too crazy about this solution. I was quite messy getting it to fit. I would like to make holes in the the edge of the protoboard matching ALL the female headers of the Arduino. That seems to be a better solution. But like I said I don't have a drill and my robot budget is at zero for the time being, since I have recently bought all the things I needed to get started :(

At least as of about a month ago, Radio Shack would sometimes have the etching solution in stock.  You may want to call before you go out there because availability can be spotty.

There is an excellent tutorial on etching your own printed circuit boards at http://www.robotroom.com/PCB.html, although it's a little dated.  Etching your own boards is very satisfying and fun.  You'll be surprised at what you can do with a little practice.

For the shakey-ness in soldering, I found a pair of 2.0 power reading glasses make it alot easier to see what you're doing, and (for some reason), I'm not as shakey when soldering with them.