Investigate Multiplexer

[ghost]

Looks like someone went to town on soldering this, and soldered everything together onto a single track. Anyone know anything about this? Primarily, does it still work?

Also, link to product page, with some nice information on usage: https://www.pololu.com/product/721

[Danyc0]

yea, the ground and power lines should be shorted together to give a common ground and power. It worked last time I saw it!

[ghost]

I'll desolder all the pins and give it a test then!

[Danyc0]

I'd really suggest not doing that! Desoldering that would be virtually impossible. Just test it without taking of the veroboard.

[ghost]

Argh, so much conflicting information! That's not a bad thing necessarily, though.

I forget who said it, but someone working on Kitty with us yesterday suggested we desoldered it so we could see if it was working, but that it would be very difficult to do.

I'll give it a test, then pawn the decision of desoldering off to someone more experienced, then create a separate issue to go from there. Probably leave this one going in case we need to go an alternative route.

That sounds like a better plan to me, at least.

[naturesyouth]

the soldering station in the dsl has a solder pump/iron attachment, if it still works it should make short work of desoldering the pins.

[Tebazil12]

Danyc0 are all the pins connecting to the veriboard ground and power? All 13pins on both rows are soldered together (which can't be seen well here)

[Danyc0]

I'm not entirely sure what you mean, but all 13 grounds should be connected together

[Danyc0]

Why does someone want to desolder it anyway?

[Tebazil12]

There are 13 grounds?

[Tebazil12]

We wanted to desolder it because it looked like someone soldered everything together when it wasn't meant to be. Is there any documentation anywhere about this?

[Danyc0]

So each set of three pins is designed to go to a different servo connector(not necessarily a servo, but a servo connector, for example those found on the RC modules). So one row is always ground, and should be common. IIRC this is the only common ground between the servos and the computers. The multiplexor is powered off the 5v power out from the sail which, and then the RC module is powered off the multiplexor (it has to be like that for the winch to work properly). The ground out of the winch is connected to the multiplexor, and so is the ground from the arduino, which is how we get the common ground. The rudder servo should not be powered off the multiplexor, it should be powered from the same place as the winch, directly off the battery. Therefore the only power connections to the multiplexor are: 5v Power in from the winch to the multiplexor Power out to the RC and therefore it's OK for them to all be connected together.

The data lines should NOT all be connected together, they are as follows: Data in from the RC (Sail) Data in from the RC (Rudder) Data in from the RC (Switch). This is channel 5 and is used to switch between RC and Arduino control. It defaults to arduino control is no signal is detected (e.g RC remote is off or out of range) Data in from the Arduino (Sail) Data in from the Arduino (Rudder) Data out to the winch Data out to the rudder servo

See the online docs for the multiplexor for more info. Specifically on the importance of the jumper wire, and the difference between master and slave.

[Danyc0]

The common ground is vitally important to get the arduino controlling the servos

[ghost]

Here is an image of the soldering atop the veriboard. Hopefully you lot can make some more informed decisions from it.

Ignore the bending/deformation. I had to take the picture through the magnifier to get enough light onto it.

[ghost]

I've given it a clean. There's no connection between the two rows, so definitely deliberate. I think that was apparent from the above, though.

[Danyc0]

Yea that's fine, it's just the ground and 5v lines which are joined. It's the 3rd row which shouldn't be joined