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[on:]

Hello,

I am trying to build a circuit using a Wiimote IR camera (Pixart sensor) as shown here: http://letsmakerobots.com/node/7752 .

However I have tried to solder wires onto the camera's pins and they are very fragile. Some of them got broken just because the wires are yet too heavy even if they are thin. As the situation appeared hopeless I cut the little box containing the camera to see if I could find a solution.

You can see the exposed camera. There are eight copper lines but the pitch is something like 0.875 mm so it seems quite impossible for me to solder such a thing. Therefore I am thinking about using a connector with pins pressing on the little PCB such as it was in the broken box (see pictures) or in RJ connectors. RJ45 connectors have 8 pins and can be tied to a cable by crimping but their pitch is bigger so they can't be used. Is there any connector I could use to avoid soldering that dwarf-thing ?


Thank you in advance.

[Reply #1 on:]

I don't know about a connector to fit that, but when in a pinch, I use 30AWG wire wrapping wire which I can solder to really small surfaces, and connect to a larger board where bigger wire can be used, if needed.

Of course, 30AWG wire can't handle a lot of current, but in most cases when soldering to a tiny connector, there isn't a lot of current required. 

[Reply #2 on:]

Thanks, I'll try that if I can't find a solderless solution.

[Reply #3 on:]

I guess the pitch corresponds to SMD standards.

[Reply #4 on:]

Wow! There's a discrete module inside the box inside the box!

One approach...

Make a little PCB! Lay down a "fan" of etch resist lines leading to where eventually you will have the tiny fingers. (The distal ends of the fan lines will be where you will eventually attach your wires.) Then, where the fan lines meet, where you'll make the tiny fingers, with a sharp tool, scratch away the resist where it isn't wanted.

Etch the board

Tin the surface of the "fingers".

More on doing your own PCBs at...

http://www.arunet.co.uk/tkboyd/ele1bp.htm

Postion the wimote sensor over the tinned fingers. Add a little flux, if you can... but not "plumbing" acid flux!... heat on a hotplate (or inverted laudry iron)


(Or just buy a new Wiimote to hack! Send me a private message if you would "sell" your exisiting sensor to me in exchange for a contribution (how much?) to a charity (US or UK), and tell me if you would rather send it to US or UK. Also tell me if you've tried soldering to the internal module yet... that will affect my interest!)

[Reply #5 on:]

Finally I soldered cables directly on the sensor's back, not 30AWG abd I applied some glue on the back afterwards to prevent disconnections. I'll publish a photo later. However I haven't tested the sensor yet so I don't know if this is this is a success or a failure and I won't do it immediately because I need additional components for the circuit.

Rather than extracting the sensor a possible alternative would consist in cutting a part of the Wiimote's PCB itself.

If my sensor is in good condition I don't plan to sell it. However if I have done it anyone can do it. You can buy a second hand Wiimote for a low price, especially in the USA. Some people even sell several broken units in a global package. I guess these are perfect candidates to extract the sensors.