Introduction: An Aesthetically Pleasing Wireless Wii Sensor Bar

By Patrick's Projects
About: I study Aerospace Engineering at RMIT, in the hope that one day I will be able to bring about the return of intercontinental airship cruises. Until then I like to make stuff in the shed, and surf instructables

Author's note:
Among all of the instructables on DIY Wii sensor bars I noticed most of them were made out of cardboard or other equally hideous material, so I decided it was time to submit an 'ible on a Wii sensor bar that works and actually looks nice too. Just because it's DIY doesn't mean it can't be beautiful

Intro

The Nintendo Wii is arguably the coolest game console ever made, and this is reflected in its December 2009 recored for the best selling console in a single month. The reason for its success is not amazing graphics, which Sony’s Playstation 3 relies on, or lots of gore and adrenaline, like Microsoft’s Xbox 360, but the unique and immersive gameplay offered by its controller - the Wii remote.

Interaction with the Wii is achieved through accelerometers, gyroscopes, and and an infra-red camera inside the Wii remote. This project focuses on the infra-red part of the control system - specifically the sensor bar which sits atop the player’s television, to let the Wii remote know where it is and where it is pointing.

This is my take on a DIY homemade Nintendo Wii wireless sensor bar.

The beauty of DIY is that you can choose how it looks, and out of what materials it is made. I took this opportunity to indulge my inner Steampunk, even if that made things a bit more awkward.

Step 1: Theory

Contrary to popular belief, the complicated electronics and tracking systems are not actually in the “sensor bar”, which is connected by a wire to the Wii, but inside the Wii remote, and that information is sent wirelessly (via bluetooth) to the Wii. This makes my life easier, as it means that the wire connecting the sensor bar to the Wii actually only carries power, no information, So to make a wireless sensor bar, the only thing I need to do is supply power - no wireless data transmission.


The sensor bar works thus: there are a number of infra-red LEDs (ten I think) which are invisible to the human eye, but can be seen by the Wii remote’s infra-red camera. That’s it. That’s all there is to it. To make things even simpler, after doing a quick bit of research, You only need four LEDs for a perfectly functional sensor bar. Dunno why the other six are there.

Step 2: Materials

What I used:

- Recycled Wood
- 4 Infra-red LEDs
- Wire
- Switch
- Small nuts and bolts (2 of each)
- Scrap sheet metal

- A saw
- Drill press
- Router
- Hammer
- Soldering iron
- PVA glue
- Sand paper

Step 3: Step 1: Cutting the Wood.

I cut one piece for the face of the sensor bar, 240 mm in length (the same size as the official sensor bar).

Another two small pieces to hold the batteries (2x AA) on either end, and one to hold them against the face, as well as hold the face vertical. Then I cut out a section of this last piece , where the batteries would fit.

Step 4: Step 2: LED Holes

All the tracking calculations done by the Wii remote are based on a known size of sensor bar. In this way it can calculate how far away from, and at what angle to the television it is, based on perspective. So I drilled four pilot holes 170mm apart, and 220mm apart, then I drilled those holes out to 4mm HALF the depth into the face, and 3mm the rest of the way. I could then insert the LEDs, and they poked out the other side without pushing all the way out the other side.

Note: The official sensor bar has 10 LEDs - this smooths the motion of the cursor, but the remote only tracks 4 LEDs and any one time, so 4 are sufficient and the decrease in smoothness is barely noticeable.

Step 5: Step 3: Routing

I haven’t yet used a router on any of these projects, so I thought this might be a good excuse. I gouged out a space in the middle, slightly less than the width of a AA battery, and twice the length, and then two depressions on either side to slot in the battery holders.

Step 6: Step 4: Battery Holder

Without buying a horrible-looking plastic battery holder, I figured I could connect the batteries to the circuit by wedging them in between to bolts. Unscrew the bolts to replace batteries, tighten to complete the circuit.

I drilled bolt-sized holes in the to edge-pieces of wood, and widened them HALF way into the wood. Here I hammered a nut into the widening to create a thread.

I glued these into place, made sure the batteries fat in, and glued on the stand.

Step 7: Step 5: Switch

In order to mount the switch, I bent a scrap piece of metal (nicely cut and rounded of course) into an L, drilled out the appropriate holes, and screwed to the back of the wooden face. The switch slid snugly in and I tightened the nut around the neck.

I then used the soldering iron burn an “on” and “off” into the top of the face.

Step 8: Step 6: the Circuit

The sensible thing here would have been to use insulated electrical wire - the most common, if not ONLY, wire used for electronics, but that was not aesthetically suitable for what I wanted. So I took a piece which consisted of a fairly thick single strand instead of many thin strands, and stripped the insulation completely, leaving only bare wire. This looked much cooler, although it took a bit more planning to make sure no wires crossed.  I wired the circuit according to the diagram below - two sets of LEDs in series, each set in parallel, as well as a 2.2 ohm resistor which is not in the diagram . I used tiny spots of PVA glue to hold the wire down the the sensor bar.

Step 9: Step 8: Add an On/off Light

No more silly wire going everywhere! (Apart from the Wii’s power chord and the AV cable). Switched this baby on, the Wii remote recognised it, and worked flawlessly.

I did, however, forget to turn the sensor bar off when I had finished playing. The problem with infra-red LEDs, is you can’t tell if they’re on or off! This happened three more times before I decided to do something about it.

I drilled another hole - big halfway, small all the way through - and put in a VISIBLE blue LED, quickly wired it up (which was really difficult because of uninsulated wires, but I ended up crossing wires where I had used PVA - a great insulator!). Now there were four infra-red LEDs, which we can’t see but the Wii remote can, and one blue LED, which we can see but the Wii remote can’t. Never since have I left the sensor bar on accidentally.