Circuit-bending a Funky Furby #1: de-skinning

Whilst there’s quite a few resources available online to help out with any planned circuit-bending of a regular furby, I’ve been unsuccessful in my searches for information relating to circuit-bending their larger relative, the Funky Furby.

This is probably one of the reasons why the purple and green critter I picked up at a carboot sale over the summer has been sat on my hack-shelf for so long, without even so much as having had fresh batteries put in it.

It is also the reason why I’m going to document as much of the process here as I can, starting with today’s instalment: de-skinning.

The first task is to remove the feet. This is likely to be the biggest hurdle due to the need for a triangular-shaped screwdriver. If you’ve got that (and a normal, small-sized cross-head screwdriver), then the rest is really quite straightforward.

The inner screw that joins the feet to the main body

After removing the two screws in the base of each foot, you can lift off the fleshy toe bit to reveal a second, black mount. This is where the feet connect to the main body, so you’ll need to remove these too. Once you have removed these (the screws are quite long) put all the foot parts and screws to one side – you’ll need these again later.

Under the feet

Removing the black mounts reveals a panel of plain material (rather than fur) with a small hole in it. If you poke around through this hole, back in the direction towards the battery compartment, you should be able to hook a finger (or maybe a screwdriver) under the black plastic strip that is sewn onto the white cloth along the corner edge where the battery compartment sticks up. Pull hard to undo the clip and free the fabric.

The tabs that hold the fabric in place around the base

The tabs that hold the fabric in place around the base

Some of the tabs on my furby came out ok, but one or two snapped. Your mileage may vary…

After that, it’s a case of gradually peeling the fur up over the top of the furby.

Skin peel

It’s easiest to work up over the back and bring the pelt over the front of the face. There are a few more of those tab things, and a few other places where you need to unhook bits and pieces, but you don’t need to snip any of the stitching or anything around the face plate – the aim is just to clear the fur layer from the back half of the shell and any of the articulated bits coming out from the inside of the shell.

The tips of the ear levers need to be unpopped.

The eyebrow elastic needs unhooking from here

Once you have done this, you can unscrew the two halves of the shell and the fur, still attached by the face plate to the front half, can just stay how it is. The microphone is attached to the front half of the shell – unscrew this so you can remove the furby innards completely.

Furby innards revealed

From here you can reattach the feet to give the little critter some stability and then you can do whatever you’re going to do with the electronics…

Kind of cute...

Circuitboard easily accesible on the side

As I said, I haven’t found any references for bend points, so there’s a high chance the furby won’t make it through the next stage where I noodle around on the circuitboard looking for glitches. I made sure to get some video of him doing his stuff before I went any further:

Funky Furby from nikkipugh on Vimeo.

…after which I did actually Read The Manual and found out that you have to play music at it for it to dance!

I need to rig up some sort of jig or stand to hold the furby off the ground for the next stage – triggering sounds also means triggering movement and that makes it really difficult to work on the circuitboard to try and find the bends.

Hopefully the furby will survive long enough to have something to put in the next of what is planned to be a series of posts documenting the circuitbending process…

hippo joy

hippo joy from nikkipugh on Vimeo.

I’m liking this circuit-bending stuff. It’s making me do things I don’t want to do.

The particular comfort zone edges I’ve noticed are:

• Restraining myself from immediately unscrewing the back and tinkering with the innards without having properly explored what the ‘normal’ behaviour is first. I must make more of an effort to document this too.
• Choosing the 3 or 4 bends from several that I’ll try and work with. This is usually a balance between the “awesome!” and the practicality of getting wires and soldering irons where they need to get to. I ‘lost’ a really nice bend in the hippo – the behaviour changed when I soldered the switch wires onto the board. I’m starting to get into the habit of making audio recordings of the initial noodling noises. [audio:http://npugh.co.uk/media/hippo.mp3]
• Revising the previous decisions, based on what switches you can accommodate in the shell.
• Making the first incision. Usually my electric drill is hilariously large compared to the toy I’m working on: one of these days the toy’s just going to disintegrate. It’s also a very definite point of no return.
• I’m slowly getting better at drilling holes a few sizes too slow and then taking them up to size with a file. Neater results, but there’s still room for a lot more improvement. I’ve also started thinking a bit more about the feel of the switches – adding in rubber o-rings to cushion body contact points etc.
• Similarly for the first solder, but given extra edge by the memory of all the circuit boards I’ve managed to kill in the past.
• I’ve circuit-bent a few toys now, all with similar push-to-make switches and body contacts. An important edge is coming up where I’ll have to learn new stuff. With the hippo bend I made myself repurpose the existing switches. It’s a bit of a bodge, but it was worth the brain-wracking to come up with a (hopefully more than temporary) solution that a) works and b) is satisfying in the way that it looks and touches.

A Flickr set of images showing the hippo’s internal gubbins is at http://www.flickr.com/photos/nikki_pugh/sets/72157622183430094/detail/

untitled

First steps in circuit-bending

I’ve been trying my hand at hacking some kids’ toys ahead of the “noobs attempt circuit bending” event I’m holding at my place next weekend.

A quick trawl of the charity shops in King’s Heath gave me 3 things to work on: a cow, a stereo and a keyboardy thing. 2 days in and I’ve already killed the cow and the stereo.

The cow was the first to go due to careless random shorting of points on the circuit-board upstream of (or possibly across) resistors. Even without a voice though, the cow is all sorts of awesome, so I’m sure it will house some sort of project in the near future.

2nd-up was a little orange boombox with the usual assortment of play and fast-forward buttons, but also a neat little contrivance where putting different plastic ‘CDs’ in the tray would push different combinations of switches and change the playlist of songs. (Is it wrong to get excited about a switch?!)

Noodling around on the circuit-board was quite disappointing until I tried the lick’n’press method. Behold! Wibbling a damp finger over R1 gives a nice Theremin style distortion of your nursery rhymes! That’ll do.

I soldered a couple of wires to each end of the resistor and then connected the other ends of these to some split pins mounted on the top of the plastic casing.

I could now control the degree of distortion by varying how far apart the contacts with my body were (the body acts as a resistor: one thumb bridging the contacts < two fingers on same hand bridging the contacts < a finger from each hand bridging the contacts). Using a wet thumb would not provide enough resistance and the chip would short out and stop playing music - so I added a push-to-break reset switch between the batteries and the circuit board so I didn't have to keep taking the batteries out each time I needed to restart.

I also added 3 slide switches so I could change the track selection without having to change CDs.

After reassembling the stereo and finally figuring out where the left-over piece went, I spent a long time exploring different combinations and effects. ***bliss!*** [and coming from someone who considers themself to have negligible musical ability, that’s some pretty powerful bleeping to hold my attention for long enough that it was probably starting to really annoy the neighbours!]

So anyway, all was good until I noticed the demo button wasn’t working because one of the wires I’d added was running between it and the circuit board. In moving the wire I managed to detach it from the board and then in trying to reattach it I managed to ping the resistor off the board too.

R1 is a tiny-beyond-description surface mount jobby located right next to the black dot where all the magic happens. Needless to say I managed to bork everything in trying to make the simple repair. Cue much frustration and swearing!

Oh well, I’ve learned a lot in the process, made some sweet, sweet, music …and also become hopelessly addicted to circuit-bending. Guess I’m off to the car boot sale tomorrow morning to pick up some more things to break!