Just some pics of Andy’s game on Monday.
Just some pics of Andy’s game on Monday.
It ain’t finished yet, but here it is so far. I’m doing the electronics and the panels, Bevis is doing everything else 🙂 .
I was concerned that the LEDs wouldn’t be bright enough, that it would be “is that turned on?”
You can’t look directly into them. I mean, you can, but then its several seconds before you can look at anything else. With a nice orangy-yellow, this thing looks molten.
The main thing is that you cannot drive something like that off a digital out – you will fry your arduino. I am driving these with the 5v off the arduino board via a darlington pair array. This means that power is coming off the regulator, not off the microprocessor.
Darlington pair array chips are designed for stepper motors and will happily handle 24v. They switch fast and have almost no resistance when driven (otherwise driving a motor would let the smoke out). The arduino analog out is pulse-width modulated, so no worries. Don’t need to use the flyback diodes, because the load is not inductive.
The darlington array shorts its output to ground when driven, so this means using common-anode LEDs.
I will etch some eldrich runes into the panels with the dremel. The idea is that not only will this catch the light, but with 2 differently-coloured LEDs in the base, different parts should catch different bis of the light. The arduino has six analog outs, so the LEDs are wired up as two sets of four on opposite corners.
I used single-core hookup wire for the loom, which was probably a mistake.
As for code – I just bodged something up this evening. light cycles between reddish and yellowish every second or so, using a slightly different period for the two sets. Won’t really know how it looks with the runes until we have runes. May need to make the colours more dramatic.
Make Hack Void is a group of dudes who have managed to lease a horrible old government building – the old water police building at Lake Ginninderra. This space is the eponymous ‘void’ of the title. A little industrial and ugly, but tools line the walls, and the table we sat at had a powerstrip down the middle, with dozens of power points. Which is what you want.
Tonight (and again this Saturday) they ran an Introduction to Arduino workshop. It was great.
For me, the best part was Stephen getting the kits together. One hurdle to getting started with this stuff is “what am I going to need?”. Sourcing the bits. Attendees were told to bring a laptop loaded with the Arduino software (which is free at the link he gave), and he really did provide everything else. There was a moment when I thought “crap – I didn’t bring a serial cable!” but no – when the moment came Stephen tossed a short serial cable to each of us.
It was all thought of, is what I am saying.
With respect to making it all go, Stephen had prepared six mini-projects. We did three, which is always the way – you panic about not having enough material and it always turns out you have way too much.
Project 0 was hello world, using the Arduino serial interface and the GUI running on your laptop.
Project 1 was Das Blinkenlights. Make an LED blink.
Project 2 was the very fun tricolor LED.
And as we were short of time, we skipped forward to the peizo buzzer.
We didn’t get to making the motor go, but it really doesn’t matter. Simply getting the gear going at all is the big step.
We chewed up time attempting to explain to people how to program – “this is a variable, this is an if statement”. I very much doubt that anyone has ever absorbed the Zen by having someone give a talk on control structures: you need context.
Stephen had people type the code off the projector rather than copy it off the web. I agree: there’s something mystical about it when you do it the hard way. The problem is time in a session like this – people who aren’t programmers aren’t instinctively going to put in all the semicolons, and they chewed up time fixing compilation errors.
Perhaps something that would work better is “here is some code, get your chip working, ok – now hack up the code to do X”. Change the blink rate, the colours – whatever. For instance, the pezio example could have made the chip sound for 3 seconds, then add a switch, then add a potentiometer.
But aside from that, it’s all good. I’m not sure what I might want to – you know – do with the board now that I have it, but I can do anything I want. What I really want is a thing to open my blinds in the morning. I have a streetlight outside, its a pain in the butt. The kit has a light sensor, I will need a somewhat more grunty motor to work the twisty thing on the blind.
Say: maybe what I need is two light sensors, one with a coloured gel to filter out the streetlight. I might be able to tell when it’s daylight by comparing the two. First order of business, then, would be to set up the sensor and collect data and then see if I can derive a rule for when to open the blinds.
The point being that with the Arduino, this project is doable. I wouldn’t have had the confidence or the impetus to wander into Jaycar and get started by myself, wouldn’t have known what to get. Having the guys there was very worthwhile.
You know – the session was not just an introduction to Arduino, it was an introduction to the MHV community. That’s the hidden purpose behind that nice lasercut mounting board. The message being: “we have guys here who can produce this sort of stuff”. And they do.
That’s the point.