WowWee FlyTech Lightstar Hack: See What's InsidePosted by Rudolph on Monday, 23 March 2009
If you don't know what the WowWee Lightstar is, well, you're starting in the wrong place. Please take a moment to get acquainted with the Lightstar, then come on back. I'll wait.
You're back? Good, glad to see you return. Now I need to give you some proper warning regarding what you're about to see. This article contains graphic representations of the insides of a cute little flying toy. Those with weak constitutions may want to avert their eyes. Those with young children may want to send them to another room (because they'll want to try this too!). For larger versions of the photos click the photo to see it in the gallery.
First we'll begin with the remote. After removing the battery cover and the batteries themselves, remove the three screws on the left cover. Gently seperate the two halves, and you'll be greeted by the circuitboard. The charging cord has a screw strain-relief on the left shell, removing this isn't quite enough to remove the cord. To remove the cord you'll need to desolder its wires.
After removing the two screws holding the board to the battery tray you can try lifting the board. You may find a bit of glue holding the board down, just stretch it a bit and nip it with a sharp object. Once you have the board off the thumbwheel will want to fall out. Go ahead and slide it off sideways and put it somewhere safe. You will then be able to see the scroll mechanism appears to be a simple potentiometer.
The White Box
You've been patient, now it's time to dig into the flying toy itself. The first area of interest will be the little white box on one side. After a close inspection it appears the plastic started life as two pieces, but has been glued and/or "welded" shut. Very gently slide an Xacto knife between the box "lid" and the black strut to seperate one side. The other three sides each have a post going through the bottom box. This post has also been glued or melted into place.
I tried drilling through the post by spinning a 5/64" drill with my finngers, but lacking a pin vise I drilled my hand instead. Don't do that. Instead just "shave" the top off the three visible pin nubs with your knife. After a bit of patient slicing around the perimeter of the box you should finally be able to work a flat screwdriver in the seam to start seperating things. Work slowly around the whole box, don't get carried away. If you hear something crack you may need to do more seam slicing or post shaving. If any of the posts do break, they're just plastic, nothing a little tape or glue won't fix.
Once inside the box you'll find the battery and a small circuitboard. On the board is a tiny SMD blue LED, and three wire connections labled "P+", "P-", and "LED". Two more connections labled "B+" and "B-" go to the battery. The battery is labled "3.7V 30mAh" with a part number on the front, and the name "FullRiver" on the back with a "don't throw in trash" warning picture.
Look around the middle of the Lightstar, you'll barely see a seam where the small top foam piece is glued to the bottom wing/blade piece. Gently slice along this seam with a sharp knife, all the way around the body. Take small slices, don't be stabby. Over the switch and the charging port the top part is also glued to a plastic housing contained inside. You'll need to slice through the glue here as well. Don't worry too much, all the electronics are inside the plastic housing, just make sure your knife is on the outside of the plastic. As long as you're not too violent you'll easily be able to avoid the fine parts.
Once inside you'll see the top foam part had a couple extended parts that fit inside the wing body, which have now been sliced through. As those appear to be glued on the sides there isn't much way around this. It should not cause any lasting damage though.
After a little more careful slicing around and under the plastic housing you should be able to remove everything from the foam wing body. Immediately you can see the IR receiver sticking out of the top of the housing. When assembled this part is covered by the foam, there is no window or lens. Apparently EPP foam is invisible to infrared.
Turning over the electronics housing you'll notice it's a very thin cover on the bottom. You'll also likely see some more glue and foam still stuck to it, clean that off for easier viewing of six little retention tabs. The tabs appear to be glued/melted into place as well, but they are not quite as difficult as the other plastic box. Use your fingernails to seperate the cover from the housing, one tab at a time, and it should just let go without destroying anything.
Once inside you'll see another circuit board with all the wires, switch, and charging jack attached. Hidden under the epoxy blob is yet another unknown chip. You'll also see a few surface mount resistors and capacitors, and one bright green surface mount LED. You can gently pull this board out, just be careful of the IR receiver that extends through the housing. It may take a bit of wiggling about to get the wires to cooperate in letting go of the receiver.
Overall there isn't much to a Lightstar. Everything is fairly tightly packed inside, and it obviously isn't intended to be dismantled. Fortunately, everything shown above should be easily repaired with a little bit of foam-safe airplane glue. Do not use regular CA or superglue on the foam or you'll end up with a molten blob of goo on your desk. You can use superglue on the plastic boxes, just make sure they're fully dry before sticking anything back inside the foam.
Naturally my interest in taking a Lightstar apart was to find out its hacking/modding potential. As such, before I started slicing things I tried to see what kind of payload capacity this thing has. First off I tried taping a US quarter to the bottom. As expected the Lightstar could barely spin with that weight. Next up was a US nickel, which was light enough to allow spin, but no lift. Finally with a US dime taped up the Lightstar was able to lift off and hover about 10 to 12 inches off the ground. It seems a dime weighs in at about 2.2 grams, so I imagine the Lightstar should be able to lift a load of one gram enough to fly at a reasonable height. Perhaps with some lightening of the body before reassembly it could handle even more.
Now I just need to think up something to hack into it!