A spooOOOOoooky project!

This is a fun one.

It’s also a testament to how nifty and easy it is to quickly whip up a project with Arduinos, provided you have enough of a “critical mass”, as I’ve called it before, of other stuff that you might end up needing.

How was this one born? Well, there was a Halloween grad student party our school was throwing, on a Friday night. It’s… honestly, really the type of thing I, or any grad student, should go to. We’re mostly isolated from other grad students, and these parties have typically gotten pretty raucous when I’ve gone to them. However, that night, I really wasn’t feelin it. I got home from work/the gym kind of late, hadn’t eaten, and the party was downtown. I think it might’ve also been raining or something, adding to the “I don’t want to go out” side of the scale. read more

Low power Arduinos, part 1

As part of an ongoing project, I wanted to see how low I could get the power consumption of Arduinos to go. The reason is as follows. When getting back into Arduinos a few months ago, I wanted to try a telemetry project of some sort, collecting data remotely and sending it back. Ideally, the idea would be to collect data from different places and analyze the aggregate in some cool way, but that’s a story for another post.

The point I was going for, though, is that I wanted to put these Arduinos in places that wouldn’t have constant access to power, so that already means using a battery. Using a battery to power an Arduino isn’t a big deal (plenty of people do it for portable projects), but once you’re looking at long term powering without recharging, it’s a different story. read more

Manual ACKing with the nRF24L01

This one will be very basic to most people who have done this, but it would have been helpful to me when I started with this stuff, so I’m putting it here.

First, a little background:

In the past couple months I’ve been messing around with the nRF24L01 (just gonna call them nRF’s from now on) radio frequency (RF) modules. Arduino hobbyists love them because they’re cheap (it seems like their competitor in this arena were Zigbee chips, which people seem to say are good but very expensive) and relatively versatile and powerful. They operate in the 2.4GHz frequency range and can actually get a pretty hefty amount of range! My roommate and I did a “range test” where I took one nRF that was just spraying out a constant stream of data, and he took another nRF with an LCD attached that displayed the received data. We went to a nearby park, and literally couldn’t get far enough away from each other to make the data stop being collected, which was about 1000′ according to Google Maps. They’re a lot of fun and really open up some project possibilities, which I’ll put here as I do them. read more

Servo controller box


Woowee, this is a long one.

This is actually something I did for my job. Here’s the deal: I have this electrochemical bath that has a sample in it; one electrode is a piece of graphite, the other electrode is the sample itself. Don’t worry about what the bath does for now, but it’s important that the longer the sample is in the bath, the more the effect of the bath is on the sample. It’s pretty much linear with time.

Now, I often want to see the effect of different lengths of time in the bath, with all other variables staying the same. The way I’ve done this in the past was to paint nail polish over parts of the sample (nail polish protects the covered part of the sample from the effect of the bath), put it in the bath for some amount of time, then take it out, either remove that nail polish, or add more, and put the sample back in for more time, etc. So basically you can have different length times on the same piece, which is useful for consistency and visually looks good. read more