Arduino and similars

I used to love buying those magazines that came with a PCB and instructions to build simple electronic things but components were hard to find and I eventually gave up.

Seeing a bunch of projects made with Arduino got me thinking it should be reasonably easy to buy this kind of stuff on the internet nowadays, maybe I should get back to the electronics hobby.

After a small search I found there are lots of kinds of Arduinos and lots of similar boards. I have absolutely no idea which one to get! They seem to be cheaper on Ebay than the official site as well.

Any tips? Can I just buy the cheapest one on Ebay? A tutorial on how to hook up motors, sensors and stuff would be nice. Programming won't be a problem, I got plenty of experience with that

Depends what kind of stuff you want to be able to do with it. I would recommend sticking to the Duemilanove, Uno or Mega variants, as they have onboard USB serial interfaces, making it easier and faster to upload code and interface them to your computer.

They are also the stock shape boards and have many shields available for them, such as motor drivers.

The eBay ones are known as "clones", and are exactly the same components as the genuine ones, so yes you are fine ordering them from eBay.

I have had a lot to do with both the Arduino and Picaxe processors. I have to admit I like the Picaxe because of its simplicity and Basic language, but I have moved to the Arduino lately as it has a large user base, there are lots of projects out there for it, and it can be powered from a USB port or Lion pack so no mucking around with breadboard power supplies or batteries.

Spark Fun electronics have some really good tutorials on it including an arduino buying guide here. I'd suggest you start with the Uno (I don't think the Duemilanove is still available). Sparkfun also have some really good "Getting Started" tutorials as does Lady Ada's site

I tend to use the smaller "mini pro" boards for embedded projects and usually prototype on breadboard with an Arduino Uno clone using this arrangement.

Cool, thanks! I'll post if I make anything interesting with it

Yes they are easy to hook up and tonnes of fun. I built a radio station controller (that still needs more work to fend off RFI) using one. I connected mine to a temperature probe and a relay board. The hardest part was soldering the SOIC8 chip for the K type thermocouple, but you can buy presoldered units (I just happened to have 5 max 6675 chips handy, and a breakout board for one (turns it into a DIP 8 ic)

Before that I programmed it up as a dedicated thermostat, a bomb timer (fake of course) and a voltage meter.

The arduino architecture is awesome stuff to play with, and the language is not far off basic, so if you can program a commodore 64, you can program an arduino

Cool, I already ordered mine but it's gonna take quite some time to get here!

As you said, I thought C would be difficult but its not that far off basic as I found.

I have even made an FM band spectrum analyzer with one and an LCD shield.

I'm good with SOIC chips its the 0.635mm SSOP and TSSOP ones I get the apprentice to do! My 40+ eyeballs aren't what they used to be..

Hehe, I'm enjoying it while I can! I can do TQFP by hand now .. we'll see about that in a few years time

Oh I can still JUST do them with high magnification and no coffee but it takes a long time... and a few retries usually. We are looking at building a laser soldering device to help

I was just thinking of a laser soldering device myself. I was going to say "wouldnt it be cool to have a robitic laser solder for these tiny chips. Line them up, push go, and a few flashes from a ruby laser later and the chip is soldered."

Of course then you mis align the laser robot, and he punches a hole right through a $30 chip. Oops

On a serious note, using reflow paste and a variable power laser, it could be possible to laser solder them. You'd need a few watts of power, and use the low power setting to "focus" the laser on the leg and land, and then hit the go button, just like laser surgery (except eye) works. Align the laser on the tissue, hit the pedal and the laser does its thing.

Write a computer program with the different chip types embedded or available as a macro, and it could all be automated...

me: "I have an SOIC 16"
Computer: "Aim laser at pin one".
me: "Done"
Computer: "Demonstrating laser path"
(the computer now goes ahead at low power and makes a bleep each time it would step up to high power. At the same time it turns the laser off for a moment so you can follow).
Computer: "is this correct"
Me: (answer yes or no).
Computer: If yes, go do the solder job. If no, go to start.

it could even be controlled by an Arduino itself

I was going to use a more manual system with two 1mW 635 reds for aiming, a CCD microscope and 10" LCD. The operator positions the beam and presses a foot pedal to send a measured pulse of 808nm death ray onto a defenceless blob of solder paste.

There is somewhat of a stigma attached to computers controlling lasers I think

Reminds me of:
You: "Open the pod bay doors H.A.L.L."
Computer: "I'm afraid I can't do that dave.."

or:
You: "Computer! Stop! its burning my arm! I'm stuck!"
Computer: "I'm sorry Ben, you have been scheduled for termination"

Ben: "as you wish." Sound effects of capacitor bank charging operated by free hand.
Computer: "What are you doing Ben?"

Ben: (in best MacGyver voice): "Evening the odds a little. Capacitor bank; FIRE!"
Computer: "NOOOOOOOOOOOOoodweroorr" (sound of computer dying, laser shuts off, stuck arm is released)

Ben: "Beer anyone?? By the way which one of you wired this thing. The E-Stop isnt working."

Finally got the Arduino!
It's pretty cool, wish I had one of these when I was a kid..

I only had a 2 color LED, some resistors and a button but already made a thing that records your buttons presses for 10s and replays it on the LED. Also made a morse code blinker, you send the text by serial and it translates and blinks it


Now I gotta figure out how to control a laser and start with the interesting stuff... either:
a) laser wireless communicator (will require another arduino)
b) laser "printer" with 1W 445nm
c) robot that shoots stuff with laser

I'd rather do c but I don't have no shields or servos. How hard is it to power those small DC motors?

Sorry to bump this but I'd like to ask this before I accidentally fry my laser.

I got one of these to drive 2 motors with the Arduino. Now I'm thinking of using it to switch my 1.1W 445nm laser on and off. The datasheet says it can handle 2A (which is more than the driver draws from the batteries) but I'm not sure if there's anything else I should worry about.

What do you guys think?

It will work, but a H-bridge is unnecessarily complex/overkill to switch a laser on and off - they're designed to be able to reverse the polarity to run motors backwards, a simple NPN MOSFET/Transistor would work.

Thanks!

Today I ran some tests with a small dc motor and it generated so much interference that it caused two *other* USB ports on my computer to stop working for awhile. The arduino was being powered by USB and the H-bridge by 2x16340. The batteries' ground was connected with arduino's.
Now I'm not sure I have the guts to turn this on again with USB connected and I really need USB to be able to send commands to the arduino...
From what I've read those 8 diodes on the board should provide a free path to the back-emf, preventing it from getting to the logic part but I'm guessing something is wrong here. Any ideas?