Kosmos Build Diary

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AntRoboteer
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Re: Kosmos Build Diary

Post by AntRoboteer »

I'd suspect the issue is down to either batteries not making a solid connection in their casings (or being flat of course) or the crimped connections on the servo plug I can see you've used are not tight enough and are therefore not conducting electricity properly. Additionally, a strand of wire could be connecting one of the wires and a pin, causing some kind of short.

I think the plan of action should be:
1) Check connector for any loose strands of wire; if there are any, remove and retest
2) Take out all batteries, put batteries back in and retest
3) Change the batteries for fresh ones
4) Remove the crimped connections from the connector by very carefully levering up the small plastic clip on each wire with a tiny screwdriver, being very careful not to break them. Then while holding the clip up, slide the crimped connection and wire out of the connector. You may want to give the part of the crimp where it clamps over the wire a squeeze with pliers. Just make sure not to clamp down on any of the crimp where the pin from the receiver would enter. Try this for both the red and black and I'd advise removing the white wire entirely using this same process and leaving it out. Then, put wires back in and test.

Hopefully that helps and you can get something going soon; the chassis looks awesome, very nicely cut. Hot glue sticks really well on polycarbonate so that would be the way to do it in my eyes and also gives a bit of flex which is essential against spinners. Superglue apparently causes the polycarbonate to weaken.

I look forward to seeing your progress. Best of luck with the troubleshooting! :D
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Rocketeer13
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Re: Kosmos Build Diary

Post by Rocketeer13 »

AntRoboteer wrote:I'd suspect the issue is down to either batteries not making a solid connection in their casings (or being flat of course) or the crimped connections on the servo plug I can see you've used are not tight enough and are therefore not conducting electricity properly. Additionally, a strand of wire could be connecting one of the wires and a pin, causing some kind of short.

Hopefully that helps and you can get something going soon; the chassis looks awesome, very nicely cut. Hot glue sticks really well on polycarbonate so that would be the way to do it in my eyes and also gives a bit of flex which is essential against spinners. Superglue apparently causes the polycarbonate to weaken.

I look forward to seeing your progress. Best of luck with the troubleshooting! :D
Thank you! That's very very helpful! However, I have since completely disassembled and reassembled the servo plug, with little improvement, though I think I've determined that it's the red positive wire that is most likely the problem. It would certainly seem to be the plug that is the issue, but short of removing then reattaching the connectors, which would be a very fiddly task, I can't quite see how to progress.
I don't really think it's worth getting a replacement cable either, for a likely temporary power source, when the alternative is actually very affordable. So I think the next step, electronics wise, will be to purchase a rechargeable battery pack. Which reminds me: how exactly do you recharge them? :lol:

Thanks for the chassis tips too. That definitely makes things easier, as I'm pretty good with hot glue! I'll have to see how strong it is though, as I was worried it wouldn't be sturdy enough? But if that works out, expect to see some significant chassis progress soon! :D
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Occashokka
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Re: Kosmos Build Diary

Post by Occashokka »

Bolted panels will be stronger than hot glue generally speaking but bolts are much chunkier and can get in the way of your design, if you just try and put a line of hot glue between 2 perpendicular pieces it probably won't be strong enough but u can add some tabs/brackets to your pieces to increase the area for the glue making it much stronger
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AntRoboteer
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Re: Kosmos Build Diary

Post by AntRoboteer »

I've always used a bit of tape to join the pieces, put some glue in the corner between them, adjust the pieces to the right angle and then leave to cool. That approach is more than strong enough and the flex helps fend off spinners as the energy of the impact is absorbed in deforming the chassis.

For the charger, we've always used these: http://www.ebay.co.uk/itm/UNIVERSAL-NI- ... 100623.m-1

And you shall need an adapter so if you get the JST version of the batteries, this would be the adapter: http://www.ebay.co.uk/itm/Tamiya-JST-BE ... SwD0lUkbTi

Else if you get the Futaba version of the batteries which I've always personally used (but you need to remove the casing on the receiver to use): http://www.ebay.co.uk/itm/Tamiya-Futaba ... Swg3FUkbJ8
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Rocketeer13
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Re: Kosmos Build Diary

Post by Rocketeer13 »

First, a very brief update, but no photos this time. The body is progressing fantastically well, with all the panels cut, save for the internal supports. I can really see it coming together, and that part at least will be complete in the next few days.
AntRoboteer wrote:I've always used a bit of tape to join the pieces, put some glue in the corner between them, adjust the pieces to the right angle and then leave to cool. That approach is more than strong enough and the flex helps fend off spinners as the energy of the impact is absorbed in deforming the chassis.

For the charger, we've always used these: http://www.ebay.co.uk/itm/UNIVERSAL-NI- ... 100623.m-1

And you shall need an adapter so if you get the JST version of the batteries, this would be the adapter: http://www.ebay.co.uk/itm/Tamiya-JST-BE ... SwD0lUkbTi

Else if you get the Futaba version of the batteries which I've always personally used (but you need to remove the casing on the receiver to use): http://www.ebay.co.uk/itm/Tamiya-Futaba ... Swg3FUkbJ8
However, I've given up with getting AAAs to work, and they're far too weighty now anyway. So this is really another quick question about batteries! I'm a little confused by the connectors, and which ones will fit my transmitter. Hitec/JR obviously matches the servos I'm using, but so far only futuba and JST have been mentioned here. Does it matter what I choose? What's the difference (if at all!)?

It looks like we've got less than a month to AWS 53, which seems like a good deadline, and hopefully I'll be able to make it to Southampton for the day. Thank you everyone for your help so far! :)
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AntRoboteer
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Re: Kosmos Build Diary

Post by AntRoboteer »

Futaba connectors are black 3 pronged connectors which are identical to your servo connectors in every way except one: there's a piece of plastic on top of the connector which acts as a key so that you cannot plug in the battery the wrong way. Of course, this only helps if you are plugging into Futaba style connectors. If the connectors you are plugging into are Hitec/JR then these sockets do not tend to have clearance for the ridge and the connector will not fit.

However, the Futaba ridge is very useful to prevent damaging the batteries and hence I would recommend going for the Futaba connector versions of the batteries but removing the receiver case to allow the Futaba ridge to fit.

Hitec/JR connectors are indeed identical to your servo connectors in every way and will fit in sockets designed for Futaba but note that you will be missing the key which prevents the battery being entered the wrong way.

JST is a two pin connector and hence you can plug it in the wrong way more easily. It can technically fit into connectors designed for both Hitec/JR and Futaba. However, I'm not sure I would recommend going for JST right now because if you plug the battery into the receiver the wrong way, the receiver is going to be dead immediately in most cases.

Overall, my recommendation is to go for the Futaba variant and take the case off of the receiver to fit the ridge.
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Rhys
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Re: Kosmos Build Diary

Post by Rhys »

A flipper called Kosmos? Well this is awkward... :P
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Rocketeer13
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Re: Kosmos Build Diary

Post by Rocketeer13 »

Rhys wrote:A flipper called Kosmos? Well this is awkward... :P
:lol: Luckily it's a different spelling? As I said, mine's named after the rocket, rather than 'the cosmos' so I think we can get away with it! :P
AntRoboteer wrote:Overall, my recommendation is to go for the Futaba variant and take the case off of the receiver to fit the ridge.
Thanks! I just wanted to check to make sure I got exactly what I needed! I'll order that. Look forward for another update soon, once it arrives!! :)
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Rhys
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Re: Kosmos Build Diary

Post by Rhys »

To be fair, I think the chances of me making it to an event any time in the next decade are slim... But if I do, we could always have a grudge match for the naming rights. :wink:
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Rocketeer13
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Re: Kosmos Build Diary

Post by Rocketeer13 »

Rhys wrote:To be fair, I think the chances of me making it to an event any time in the next decade are slim... But if I do, we could always have a grudge match for the naming rights. :wink:
Challenge accepted! 8)
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