arduino, robots, cameras, and life

I really like the motor shield from adafruit industries. It is simple and it allows me to plug it in and start playing quickly. I usually have giant machines in my head, and the shield just wasn’t designed for those kind of motors.
You aren’t going to end up running your prius off of one of these controllers, but it turns out that you can almost double the max motor current draw just by soldering on some chips.
From Adafruit’s forums I figured out what ic’s I need to order (L293). Here is the label on the esd bag.

Now all that you need to do is solder them on top of the existing motor driver chips! As strange as it sounds, the theory has been vetted. Each one of those drivers can handle 600mA continuous. By stacking one on top of another they each handle ~600mA and you end up with ~1200mA! The motor shield has two driver ICs mounted on it, they are the two outer ones.

Here is a shot of the board. It is assembled, but it only has one motor driver chip per channel (‘channel’ feels weird there, but you know what I mean)

Read more

So, like many of my readers I spent the morning watching firefox time out on sparkfun’s website. Eventually the clouds parted just in time for me to see the ticker go from 70k to 98k, to 100k. Just like that the first ever (annual?) sparkfun free day was over. I was bummed. Then I started thinking about it. Everything in my cart was something I wanted, and I did have a good time this morning, and I had a good time thinking about what I was going to get, and why. I have always thought sparkfun is a really cool company, and the fact that I can’t get this stuff for free isn’t going to stop me from buying it.

Right now there are probably a few thousand people still crashing the gates of sparkfun.com trying to get in on free day. It is over. They rewarded us with the chance to get free stuff. I personally am going to thank them by buying it anyways.

Thanks Nate, thanks Sparkfun!

This is one of those projects I’ve been working on for quite a while now, but never well enough to actually put it in a box! Well.. it still has no box, but it’s much closer to a boxable form.

It is a RBBB arduino clone (but any arduino
will
work) with an ir led, a potentiometer, a resistor, and some perfboard. The perfboard is as much there to help provide a little bit of wire strain relief as it is to provide a place to mount the pot. The code simply reads the pot input and converts it into a delay() function. Then it fires the IR led with the nikon-specific magic to tell my d40 to shoot.

Here is an example of one of the timelapses I have shot.

Read more

After seeing this project from cibomahto a while ago, I finally got my act together and bought a $1 IR led from radio$hack so I could build an intervalometer for my SLR.

For those who don’t know an intervalometer is, it tells your computer to take a picture every given interval. This enables you to shoot video with a still camera over a long period of time. Sometimes you have two intervals on fancy ones. Those allow you to use the bulb setting on your camera. Right now it has two potentiometers to indicate seconds and minutes between shots. It is run from a nine volt battery, and I expect it to have fairly good battery life. Only time will tell. The IR LED can’t take too much juice! It has a status led to show when it is firing (for trouble shooting) and not a whole lot else.

This currently needs a housing and a interface. I am debating the merits of a small lcd vs just using a printed label to mark the pot positions. It’s pretty much spray and pray right now. At least it is adjustable!

I’m thinking about getting one of these and eliminating the pots completely.

Which would end up making my project very similar to this one but for a nikon.

One last thought is possibly adding the functionality to use the bulb setting and then add a bracketing ability. Isn’t technology wonderful!

I’ve been really interested in doing J4mie’s Physical Gmail Notifier ever since it came out in February. I only recently dropped into the project and got to learn a lot about python, plists, and arduino auto-reset functionality. I’m going to share what I’ve learned because I think there are lots of other people out there struggling to make it work. This page doesn’t really offer much that J4mie didn’t already say – it just says it in a different way.

I’ll post the code below – one issue with the way J4mie posted his was that it appended line numbers to everything and messed with formatting. Python is _really_ picky about formatting! All of the files are zipped HERE. It consists of three documents -

1) one python script that logs into your gmail rss feed and checks your total number of new messages. It then sends either an ‘m’ or an ‘n’ to the serial port.

2) one arduino sketch that tells the arduino to turn on or off a light based on the serial input

3) one .plist file that tells your mac (sorry pcs!) to run the python script every 60 seconds. If you run windows or linux then I’m sure there is something you can do to schedule this. You could also just set it to loop until quit. (to quit a script in terminal hit control-c)

Read more