Antabuse (aka DieSulfiram)

Making an Antweight for the next AWS. Got all the parts working together. Need to get materials and build a body now. Will most likely go for a dull 4wd pushing box for the first one just so I can get something which works. At the moment the wheels are bottle tops with rubber bands around them. Is this a terrible idea? It seems to work fine on my desk...

Thinking of either HDPE or polycarb for the protection- any thoughts?

Attachment 3891Attachment 3892

Will update when things happen.

Cheers,
James.

the milk bottle tops will suffice providing they're held onto the motors well.

Also, be careful with those batteries, the tabs underneath those black caps are a bit flimsy.

Great, they seem okay. How would you suggest holding them on? At the moment I'm just drilling holes slightly too small and squeezing them onto the shaft.

How do you mean? Which tabs are they? I'm having trouble charging them at the moment. None of the 4 seems to be taking charge...

I seriously hope you're using the correct kind of charger...

I use these cells for 3 (used to be 4) of my ants and I take that black casing off and the connector so I am left with 2 bare tabs so I can hard wire the 2 cells together into the robot. Saves me the weight of the caps and any extra connectors.

Oh, and as for the wheels, that hole won't hold for long. Did it like that on St. Jimmy and it rounded out the holes after a few fights. Not sure the best way to attach them to milk bottle tops :)

I thought milk bottle tops were made out of foil?

This is the charger I am using...
Attachment 3897
Ah I see... For now at least I'll be leaving the black tabs on but thanks for letting me know :)
Okay, I may just bring several sets so I can replace them when they get rounded out :L

What armour would people suggest for a rambot? Currently weighs about 100g. I was thinking 6mm polycarb or HDPE. Any ideas? Also, where is the best palce to source this? Thanks.

6mm polycarb is good armour for a rambot. I use it for Bulletproof and its taken the worst the spinners can throw at it.

BTW, that charger should be fine for lipos, can't see why there's a problem.

Great-thanks. Do you buy it online? Or locally?
Okay, will try poking around with the charger...

http://www.directplasticsonline.co.uk/

or ebay

Great thanks :)

Put some HDPE over antabuse. I think I overdid it a bit going for 6mm as it's not 200g :/ 100g for the armour and 100g for the innards. Thinking of going down to 3.. which *should* bring me down to exactly 150g.

Some pics:
Attachment 3913Attachment 3914

I'm not surprised that's 200g It's not standard practice to make all your robot from the same thickness material. Try and build a robot with sides. Have 6mm side peices and then you can screw thinner panels to it. Also, maybes try for a wedge?

No, I now realise that :) I was planning to put thinner material on the sides but with the wheels external to it. Is that sensible? Or not? Would 3mm HDPE be appropriate? I am also planning a wedge but it was starting to look like it might not fit into the cube (and the weight was shooting up and up) so I just made it as a box for now.
Cheers

It's better to have thinner stuff on top because ants don't much attack from the top. I built Baby Hell and Bulletproof with 6mm side panels with the wheels inside, and 1mm top and base plates. Seems to have stood up OK thus far :).

Dave- is that 1mm polycarb of HDPE? That sounds like a good plan...

Bulletproof is polycarbonate. Baby Hell is 3d printed nylon. 1mm HDPE is a bit too bendy for a base.

Okay. I think I'll go for some 2mm polycarb for the base and top then. Then see what weight I have left for the sides. How do you fix the polycarb together in Bulletproof?

M2.5 bolts through the lid and base and tapped into the 6mm edge of the polycarbonate.

The polycarb arrived today. Got it all cut out now. Just need to fix it together. While I was cutting out one of my batteries (which wasn't plugged into anything at the time) started smoking. It warped a bit and this is the result. Any idea what happened?? It wasn't plugged into anything and hasn't been for at least 24 hours (except for 2 seconds about 30 ins before when I tested the drive). Attachment 3923

Do I see two exposed pins on the left-hand side of the image? You probably accidentally dropped or knocked something metal into the battery, causing it to short the pins for a split second (which is all it takes). NEVER leave pins exposed on LiPos. At an absolute minimum always cover them with electrical tape, but preferably use plugs that only have one exposed pin, and one socket.

I see what happened there. you've somehow removed the connector that the battery plugs into, and bared the pins. these short circuited the lipo and caused your smoked battery. PLEASE be more careful with lipos.
http://i947.photobucket.com/albums/a...ps26521302.jpg

Looked at it and that is it. The connector came off with the battery and the pins must have touched. I'll reinforce it with tape now so that can't happen again.

Quote:

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Originally Posted by JamesDavies

Looked at it and that is it. The connector came off with the battery and the pins must have touched. I'll reinforce it with tape now so that can't happen again.

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As this is your first LiPo failure (most of us antweight builders have had one at one point or another), do a Google search for how to safely dispose of LiPo batteries.

As Harry says, you cannot be too careful with LiPos. I've soldered up loads of LiPo packs and cells in my time, and yet I still triple-check every single connection, solder joint, and socket by eye and with a multimeter at every single stage of the process. I also always keep anything metal far away on my workbench to where I'm working on them. Always cover anything that's exposed, and be very careful if you're ever cutting a wire to or from a battery while it's connected. I know a few people who've thought it was a good idea to cut both battery wires at the same time, only for the wires to short through the cutters they were using and go pop.

Thanks for the tips. I'll take more care when removing them in the future... And try to be super careful to avoid shorts...

I seem to remember you have to put them in a bag of salt and pop them...? As Scott says though, I'd double check with Google. Personally I've never had a failure (very unusual, I still have a few 10 year old kokam cells which seem good), but I seem to remember someone mentioning the salt thing before. I think the key is, when handling them, always assume they're about to explode or catch fire if you do the slightest thing wrong.

Quote:

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Originally Posted by JamesDavies

Looked at it and that is it. The connector came off with the battery and the pins must have touched. I'll reinforce it with tape now so that can't happen again.

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Just to confirm you can't use that battery again it must be disposed of, never use a lipo that has swelled or looks at all damaged. Sorry if you already realised this but better to be safe than sorry!

Yes- so far I've been treating them very carefully. I'll have a look and dispose of them safely.
I wasn't planning on using it again :) But thanks for mentioning it anyway :)

Attachment 3925
Remade the chassis in polycarb.

Looking good. I'd still try and get a wedge on there though. Whats it weigh?

about 125g at the moment. just enough weight for a steel scoop on the front- but there might not be enough space in the cube (4x4). Gonna make my own cube tomorrow and find out...

You can easily shorten it if it doesn't quite fit.

Attachment 3926Attachment 3927
Redone the body, shortened it a little so I can fit the scoop on. Wheels now have rubber bands glued to them for grip. With the steel scoop it now weight 135g. And I think is all finished (except I don't currently have enough working batteries so cant be 100% sure).

What's up with you batteries? I'll have some spare lipos at the AWS if you need to borrow them.

2 of them never worked- they don't seem to charge. I had 2 which did work but one shorted and died so I'm down to one functioning one... I have some in the post (hopefully) but if they dont come in time then I may have to take you up on your offer- many thanks! :)