Power and Pre June Programming Hardware Kit

I know this has been talked about before, but I couldn’t find an answer to this exact question.

I’ve finally got a working Programming Hardware Kit, the 1st one I got the usb-serial adapter was dead. I had hoped the replacement would be one of the new style ones, but looks like they have a load of old ones to get rid of 1st.

anyway the question.
would sticking a USB Y Power cable (something like this)


Between the key and the joystick, and sticking the power part of the Y into a free usb port allow the computer to power the joystick, while programming with the Kit.


I can’t answer your question, it looks like a cool idea, but do you know that you can use the USB A-A cable instead of the keys to establish the link to the robot and that the robot will power the handset? It doesn’t help when you want to debug wirelessly but it is very useful in saving batteries while programming and debugging on the bench.

Cheers Kb

I believe that it wouldn’t make a difference. All of the usb power would still be going through the programming cable. The problem is the programming cable doesn’t “pass-through” the usb power. I believe the only way to power the joystick from the programming cable would be to try to find the power within the telephone like cable connecting the orange box to the controller.

Yes, and We’ll probably end up doing that, just that being able to do it wirelessly is nicer :slight_smile:

The joystick can also get power if its connected to the cortex via the A-A cable, so if the Key on the joystick is connected to it via the Y cable it should ideally behave as if its connected as normal, and if the power part of the y cable is connected to a spare usb port, it should then inject power through the usb to the joystick…

I think the idea is to plug one male usb into the game pad where the vexnet key goes, the other male USB adapter would go in a USB port on the computer or to a 5v USB power adapter, then the vexnet key would plug into the female USB port. The 2 mail adapters seem to be very closely spaced and this one which comes up as an alternative might provide better freedom of motion for the handset.

Cheers Kb

Yes thats what I meant, and a better explanation then I managed.
and I was forgetting that the 2 males wanted to be far apart.

I see no reason why it wouldn’t work, however, any time you start to use equipment in a non-standard way you have to be careful so I would not recommend this method to students unless sanctioned by VEX.

Some users have injected regulated 5V into the programming port by making their own cable, some discussion of that here.


VEX sells a joystick wall wart but it cannot be used simultaneously with the old serial adapter. btw the serial adapter needs the 5V to power a PIC in the small orange box with the 9 pin D connector.

I would try and use a 1A capable USB hub (and I am assuming that the cortex does not support the WiFI connected to the hub, that would be cool) rather than a port on your PC, the cortex probably needs 150-200mA and the USB key perhaps 300mA so you are near the 500mA limit for a standard USB port. We did measure current at one point when running off a 9V battery (it was 400ma @ 9V) but have never bothered to measure at 5V, something for my to do list.

Another alternative some teams have used is to provide power into the battery compartment.

I’m also surprised that you received the old adapter, I thought they stopped shipping earlier this year, perhaps it’s a UK thing.

Thanks, somethings to think about.
and yes was kind of surprised when I opened the box especially as they had forgotten to send me an A-A lead and I hadn’t worried as I’d assumed there would be one in the Programming Kit.
I was even more surprised when it didn’t work and the replacement was also one of the old kits even though they had asked the warehouse to supply me with the newest kit they had…

But yes I think its a uk thing… I mean we don’t even officially have a clawbot yet…

However despite all this customer service has been great…so I’m not complaining.

Well I just tried this, Vex net in the USB hub, and the USB a-a to the handset, but as you suspected. the gamepad did not recognize the Vexnet in the hub. it would’ve been cool.

Cheers Kb

I should have mentioned I tried that too, problem is a hub is too intelligent, but would have been nice.

how about something like this?


I would think this cable would provide the power to the female plug (key) not necessarily the male end (gamepad). When I tried the hub trick it had no poer on the male plug.

Cheers Kb

That makes horrible sense, as I’d imagine they wouldn’t want to feed power back into the computer which would normally be at the male end.

however that could be sorted with a gender changer and an A-A wire, not sure if that over complicates things though.

I have made a cable such as described in this post.


I would like to note that I first tried installing the pins the same on both jacks, but found this did not work. a quick check of the ‘official’ cable showed that they were opposite pins on each jack, so I cut off the jack on the end of the joystick and reversed the pins. this worked fine. I was able to download S/W to both a Cortex and a PIC. so the pin out on the jack facing the bump on the programming cable worked with the power on pin 2 and ground on Pin 4 (i.e. the pins are as described in the wiki documentation). at the other end facing the joystick Pin 1 becomes pin 6 and Pin 2 becomes Pin 5 etc.

so now I have a cable which can be used without power to program the cortex or PIC and when using an old cell phone charger to provide 5V powers the joystick.

but be careful as this is not fully documented and as I found out not as straight forward as I expected.

Glad it works though.

Cheers Kb