Talon SRX Data Port Header

[marshall]

Originally Posted by TheOtherGuy

We're about to order some advanced circuits "barebones" compatible boards (bottom traces/pins steer clear of SRX body). We're going exclusively with AMT102V encoders, so the pinout /voltages matches those. I'll post back with info on how they turn out...

Attachment 17920

Still waiting on ours at the moment. Should be in soon though. Then it's surface mount with a hot plate time!

[Mike Copioli]

This is an example of what we had envisioned when designing the SRX encoder breakout.

We found that mounting a PCB directly to the Talon's housing is not without risk. Foreign objects such as wrenches, misplaced hands... would damage the PCB and sometimes the Talons data connector.

The other concern, there is no female counter part to the Data connector, at least not one that is keyed. This would make it possible to insert the breakout backwards, which could damage both the Talon and the down-stream device.
Since there is no easy way to enforce polarity we felt it would cause less stress for teams to have a breakout that was inline with the Talons wiring.

[wireties]

Originally Posted by marshall

Interesting. I'm digging the convergent evolution with these designs.

Are you at all worried about shorting on the bottom side of your board?

Yeah - we'll need something to prevent it shorting out and act as a thermal barrier. Suggestions?

[wireties]

Originally Posted by Mike Copioli

We found that mounting a PCB directly to the Talon's housing is not without risk. Foreign objects such as wrenches, misplaced hands... would damage the PCB and sometimes the Talons data connector.

Yeah - it would be nice if the mounting holes were positioned so that they would polarize a top-mounted board. But the data connector will be protected by the board itself. I'm thinking the board is passive and in no more danger that the kinda-thin and vulnerable 0.025 ribbon cable. We are crossing our fingers.

[Ideal_Nerd]

We are making a board that mounts to the top of the talon. We are just breaking out the the pins. We are then going to print a case to protect it. I will post pics on the 24th when we get the boards.

[Ether]

Originally Posted by Ideal_Nerd

We are making a board that mounts to the top of the talon....We are then going to print a case to protect it.

Will the case (and the board) interfere with cooling airflow around the Talon?

[RyanShoff]

There are quite a few shared projects on Oshpark for SRX breakout boards. I haven't seen if any of the designing teams have posted if they actually work.

[Ideal_Nerd]

Originally Posted by Ether

Will the case (and the board) interfere with cooling airflow around the Talon?

The board we are mounting it to is aluminum. It will act as a big heat sink.

[TheOtherGuy]

Originally Posted by Mike Copioli

This is an example of what we had envisioned when designing the SRX encoder breakout.

We found that mounting a PCB directly to the Talon's housing is not without risk. Foreign objects such as wrenches, misplaced hands... would damage the PCB and sometimes the Talons data connector.

The other concern, there is no female counter part to the Data connector, at least not one that is keyed. This would make it possible to insert the breakout backwards, which could damage both the Talon and the down-stream device.
Since there is no easy way to enforce polarity we felt it would cause less stress for teams to have a breakout that was inline with the Talons wiring.

Definitely valid concerns. I imagined it would be easier for teams to damage the ribbon cable though. With the solder pads, if anything between the Talon and encoder fails, there's a good deal of work needed to make a repair (assuming you don't have a spare cable for each of your different encoder setups prepared).

Is there a small piece of plastic you can attach that fits the slot? Or perhaps just an incredibly obvious silkscreen marking? Or some kind of molding around the board? The inline method seems a bit hokey to me Maybe I just need to play with brushless motor drivers more..

I have some gripes with the boards other than mounting (why not integrate analog + encoder and just sell 1 board? spots for pull-up resistors? etc), but I also imagine a better version will present itself in the future. Until then, ours will suffice.

[marshall]

Originally Posted by Mike Copioli

This is an example of what we had envisioned when designing the SRX encoder breakout.

We found that mounting a PCB directly to the Talon's housing is not without risk. Foreign objects such as wrenches, misplaced hands... would damage the PCB and sometimes the Talons data connector.

The other concern, there is no female counter part to the Data connector, at least not one that is keyed. This would make it possible to insert the breakout backwards, which could damage both the Talon and the down-stream device.
Since there is no easy way to enforce polarity we felt it would cause less stress for teams to have a breakout that was inline with the Talons wiring.

This definitely helps explain the design but the issue I see is one of COTS and fabrication. These boards are expensive (particularly when you have 8-10 of them on a robot). It would be nice to be able to re-use them from year to year. As the rules are currently written and the fact that they are soldered connections... not sure about that. Not that it much matters being the first year for them... Just a thought.

Perhaps there is some middle ground for a design. I'd like to see a less fragile ribbon cable though and some way to make the part work from year to year or have an easy method for connecting everything... More Weidmullers (kidding)!

[Ether]

Originally Posted by Ideal_Nerd

The board we are mounting it to is aluminum. It will act as a big heat sink.

Use thermal grease.

[Mike Copioli]

Originally Posted by marshall

I'd like to see a less fragile ribbon cable though and some way to make the part work from year to year or have an easy method for connecting everything... More Weidmullers (kidding)!

As far as I know there have not been any reported issues with the SRX ribbon cable. In fact we use the exact same cable on the Talon EOL(end of line) test.

Have you had any issues with this cable? If so would you mind describing them?

[catacon]

Originally Posted by RyanShoff

There are quite a few shared projects on Oshpark for SRX breakout boards. I haven't seen if any of the designing teams have posted if they actually work.

We just submitted ours yesterday. We should get them in soon and will report back.

[marshall]

Originally Posted by Mike Copioli

As far as I know there have not been any reported issues with the SRX ribbon cable. In fact we use the exact same cable on the Talon EOL(end of line) test.

Have you had any issues with this cable? If so would you mind describing them?

We discussed it a lot while beta testing. It's one of the reasons we decided to fabricate a board that could mount in place. It wasn't anything we saw in the field for the beta testing but I've seen issues with these .05" pins being flattened while plugging/unplugging these cables. Unlike the .1" pins, once you bend them, they are gone. I've also seen some issues with ribbon cables ripping near the headers from my PC repair days. Granted, your design does take care of those issues.

Don't get me wrong though... the SRXs are MILES... no, lightyears, ahead of the Jaguars. They are amazing products for FRC.