How to add a IR board programming connector to OSVR HDK 1.2 1.3 1.4 2

Lay HDK headset face down on a soft surface. Remove the two Phillips #00 screws from the bottom.

Turn the headset upright.

Behind the red box is a connector between a ribbon cable attached to the faceplate and a ribbon cable wrapped inside the body of the HMD. It's taped together in addition to the force of the connection, but is still somewhat fragile, so when opening, this left side should be treated as the "hinge".

There are now only two pairs of magnets at the top in the corners holding the faceplate to the body of the HMD. (In the inside image, one of the faceplate magnets is not pictured.)

There are two grooves on top, marked, to use in faceplate removal. Keeping in mind the minimal force holding the faceplate on, and the location of the faceplate connector, gently pull/fold the faceplate out and to the left. Do not use any tools for this step!

If you are following this guide to reprogram the IR board, and are able to use the "P5" programming connector - no more disassembly is required. The pink box indicates the location of P5 in an assembled HDK 1.x with the connector (1.4 units shipped with a P5-containing IR board).

Disconnect the board-to-board ribbon cable (connecting the IR board to the main circuit board) by lifting/tilting the white locking piece then gently sliding out the ribbon cable.

Flat on the surface of the IR board, about where the yellow arrow points, the orange ribbon cables (which carry the IR LEDs and additional positional tracking circuitry) connect to the IR board with the same sort of flat connector that is used between the faceplate ribbon cable and the main body.

The connector section of the ribbon cable is reinforced with a small board, which you can see just past the edge of the IR board itself. In a 1.4 or newer, as shown, it's right above the P5 connector (pink). If you come in from the front, you'll likely need a fingernail or pick/spudger. From behind the connector, a finger will probably be enough.

Once those two cables have been removed, you should be able to shimmy the IR board out: be careful not to tug on any of the orange ribbon cables (they should be attached to the HMD case with adhesive on rubber bumpers at each LED location). It's OK to press the rubber bumpers back down onto the case if the adhesive has pulled away.

First photo: connector attached, with ribbon cable unfolded out of the way for a clear view. Viewing the "top" of the board, which faces out the side of the HMD when installed.

When inside the HDK, the green arrow would be pointing out the front of the HMD.

When the orange ribbon cable with the LEDs is correctly left intact, it would actually gently bend (near the marked black line) over the IR board so that both blue arrows would point toward the top of the HMD.

Second image: connector immediately after disconnection, with both halves of the connector facing the camera. Again, ribbon cable unnaturally unfolded for ease of photography. As before, green arrows would point out the front, and blue arrows would point toward the top.

Here, you can see both the ribbon-cable side of the connector ("receptacle"), in yellow, and the board-side connector, highlighted in red. For a clearer view of how they mate, see the JAE WP7 series connector datasheet (board uses a JAE-WP7B-P040VA1) which has 3d renderings.

Here you can get a better look at the features from the previous step which may help in reassembly.

This is the board-to-board ribbon cable. Removing the main board end is much easier to re-assemble than removing the IR board end, so just leave this cable attached to the IR board while it's out.

This is the board half of the connector to the orange ribbon cables - you can see it's flat against the board and rectangular in shape (and not necessarily perfectly square with the board), which might help you visualize reconnecting it.

This is the "P5" programming header suitable for use with official, full ST-Link v2 kits with cable bundle. Earlier boards do not have this connector or even this section of circuit board jutting out - that's nothing to worry about. The pinout is a duplicate of P3.

At the bottom-center, below the STM8 microcontroller, is a pair of unpopulated headers. The P3 header, highlighted in orange, is the programming header, and thus the one we're interested in. Pin 1 and 4 are numbered in the silkscreen, and pin 1 is also marked with a dot and has a square, rather than circular, pad.

For both of my examples, I chose a CD-ROM Audio connector that I scavenged and desoldered from an old sound card. Nothing special, except that they are the right pitch (0.1 inches), 4 pins, and have a clearly labeled pin 1, so when the "notch" is down, the pins match the order of the header on the board.

Unless you come up with a clever alternative method, you'll have some bare wire here after soldering. If there's a lot, you might want to use heat shrink tubing (or at least electrical tape) to avoid the possibility of causing a short.

The particular connector you choose doesn't really matter as long as you can solder to one end of it, you can keep track of which end is pin 1, and it's the right pitch for the cable from your STM8 programmer (which is often 0.1").

You'll want to choose some wire that is not too thick (needs to fit in the holes in the circuit board) and ideally flexible enough that you can easily fold the connector and wire back into the HDK and reassemble.

The example with the red wire is solid hookup wire from a spool, 22 AWG (0.65mm diameter). It's a little stiff: it works, but it's not very bendable.

The multi-colored wire in the other example is two of the four twisted pairs out of some "riser-rated" CAT5e - 24 AWG (0.51mm diameter) solid. (I put the two pairs into heatshrink to make it tidier.) This is much nicer: flexes easier to move in and out of the headset, and less bulky. The pairs don't really matter since only one wire is a data wire.

Whatever wire you choose, you'll want 4 wires about 1.5" or 4cm long, with ends stripped and tinned so you can solder them. You'll also want to take care during the process, especially if your wires are all the same color, that you're keeping the wires in order.

Start by soldering the connector end of the wires to the connector you've chosen. How to solder is beyond the scope of this guide, but remember that you want smooth, shiny solder joints.

Insert the wires from the connector through the "top" of the board (the side with the P3 silkscreen), making sure that you've matched pin 1 of P3 with the pin 1 wire from your connector.

While holding the wires in place, carefully turn the circuit board over so that the "top" side faces down and the tinned ends of the wires protrude through the circuit board. (You may wish to use a soldering clamp or similar tool to help at this point.)

Apply flux and carefully solder all four wires (heating both pad and wire, then applying solder once hot). The solder should wick down through the plated through-hole to the other side, turning the copper pads to a silver color on both sides and smoothly reaching up the wire.

Once the solder joints have cooled (without moving!), and you are confident that they are solid, clean, and shiny all around, you can trim the excess wire protruding from the bottom of the board.

If you're using a generic, metal-cased "USB stick" style programmer, it will likely have a pinout diagram on it like this. Recall from the P3 pinout that we have 3.3V, SWIM, GND, and RST, in that order, on the board - and now on your connector!

Conveniently, this programmer has those same pins right next to each other (though in reverse order) starting at its own pin 1, indicated by that embossed arrow in the plastic. I used the cables it came with, connecting white to RST, black to GND, brown to SWIM (the data line), and red to 3.3V.

On my CD-Audio connectors, with the notch for the "tab" down, pin 1 is on the left, so that means the correct order left to right would then be red, brown, black, and white, as pictured. The cable colors may vary, but make sure the order matches.

You can now proceed with the programming!