Some backstory.
Our hackspace door used to hang open freely. It's cold in the winter, our heating is expensive, that's not cool. Or rather, it's very very cool and we don't like that.
One of our members harnessed the power of simple machines and hung a geodesic from the door through a pulley on the roof. Yeah, we have geodesic domes just lying around. Now they're hanging around.
Another member wrote some code to play an mp3 file off an SD card when the dome drops.
The last member deadbugged up an amplifier.
Oh yeah, and we attached a doll(now robot) body to the bottom of the dome and got it to quote Marvin.
Components
1×
Slightly Disadvantaged Teddy Bear
1×
LM1875
Audio ICs / Audio Amplifiers
1×
22uF polarized cap
Electronic Components / Misc. Electronic Components
2×
100uF polarized cap
Electronic Components / Misc. Electronic Components
2×
0.1uF cap
Electronic Components / Misc. Electronic Components
Unfortunately Marvin crashed just as I was about to shoot the video while waiting on a fellow team member to get off of the phone and I also cannot edit the tags for the formal submission.
I'll update this page with everything we've been hacking on over the past few days and also do a post-mortem with lessons learned!
In absence of our beloved (and glorious) leader Jarrett Jung Ill, we have been working hard behind the scenes to get Marvin up (see what I did there!) before the deadline! Using the power of the internet, we have even resorted to online scrum boards to get everything done! Admittedly, we've also resorted to get a fourth comrad on board! (Comrad Logan knows enough of just about everything to make us cower in fear.)
In the midst of deciding what to do with Marvin's head, we also did some much needed surgery for his extremities.
Here's Tim.
Remember, kids. Safety first. Gotta protect your eye.
And now we commence with the leg reassignment surgery.
Right after this, Tim's daughter caught us with the bear and we had to give it back. So no pictures of the finished thing just yet. We're waiting on Tim to steal it back on the sly.
This
can used to determine how many people are trying to talk to Marvin.
Marvin can respond, “don't
talk to me about life”
And when people stop talking, “I'd
make a suggestion, but you wouldn't listen.”
Marvin
is not on the network, you must talk to him directly. Makes it easier
for Marvin, who
enjoys
“humming
ironically because he hated humans so much”
:):
when
no one is around to talk to.
Misc
Hardware
Marvin
can stream his audio over wifi, but he has is own speakers, because
“no
one ever listens”
:):
Software
STM32F4DISCOVERY
ChibiOS
reads spi accelerometer, detects movement and communicates with the
RaspberryPI
over usb.
ChibiOS
cross complied and deployed / debugged from RaspberryPI.
Tim: Yeah. I guess I'll see if I can grab a doll that my daughter won't miss too much.
Perfect. One problem. It's an amputee.
It also has a bear head, and we need to replace that with an android head.
Let's start with that. First we prep the bear for surgery.
The first rule of our hackspace is "safety third".
This is Jarrett.
This is Jarrett's lab coat.
Appropriate PPE.
Gotta protect your eyes.
And your face.
Grab your scalpel.
At this point, we realised that we needed something to anchor the body to our geodesic dome head, so the bear's head needed to stay. You've been spared this time, bear.
Of course, we still need to improve a little bit on the audio, but because pictures - or in this case video - say more than words: here are Marvin's first words!
I took some time out to wire up a quick audio amp.
Sound quality isn't really a huge concern here, so I just grabbed a LM1875 and used an example circuit from the datasheet.
I left National Semiconductor's name in the footer please don't sue me
I wanted to get this portion done as quickly as possible, so I found a perfboard kicking around the hackspace and deadbug soldered all of the components directly to each other. I have so much affection for this method, look at this fucked up board! It's like owning a pug that runs into walls.
One of the advantages of this method is that it's very very fast. The disadvantages are that it's terrible, it looks terrible, it's very difficult to troubleshoot if something goes wrong, and the weird ground loops are probably causing some audio problems. But you know what? That all adds character. This project is going to have a lot of character.
Fun story: I wired this up in an hour or so, then went over to our power station to test it out. It's rated for up to 60v, but I was pretty sure that'd be a little much. So I set the power supply to 12v, grabbed a function generator, and set it to 1kHz.
I touched it to the input, and it nearly blew me across the room. It's pretty loud.
So here's where we're at for the amplifier. I just attached the speaker with some double-sided tape.
I'm surprised that, given the issue is with a door, you didn't try and give it one of those 'GPP's from the Sirius Cybernetics Corporation (then you can have Marvin complain about the air of smugness when someone is just about to open the door) - but like Mike - I can't wait for a video of this :-)
In Canada, at least, MG Chemicals sells an acrylic conformal coating (419C), designed for waterproofing. I use it for everything, though, the stuff smells awesome.
I do appreciate the quick prototyping that come with globby-faster-is-better soldering like you've shown on the audio circuit. My problem with doing that: if it works I never go back and remake the circuit... which means it's bound to fail later and be unfixable.
You guys should film a quick video demo of this. Specifically I want to hear how the amp sounds.