Help with choosing parts for a first robot, please.

[Coolspeedbot]

Thanks, Andy.

@CoolSpeedBot There's a 100 mm bolt which goes through the length of the block, with a barrel nut in the middle. Then there's a hole in the side of the inner bulkhead which allows it to be held in with a washer and nut. Here's a photo of one that was a bit iffy, hope it makes sense.

[ATTACH=CONFIG]5923[/ATTACH]


Right now it's the only thing that's holding the wedge and outer armour to inside - now I can see where the wedge actually sits I can bolt it to the inner bulkheads.

I see, thanks

[dotDominic]

So I just tested Venator and it actually worked! ... for about half a second...

There was a bit of a poof around the removable link as I hooked it up. The negative terminal of the link has gone black and no longer conducts. Was wondering if anyone knows what I've just done? Is this due to a naff solder joint somewhere?

Thanks,

[Anttazz]

Really hard to say, generally smoke could be from anywhere if it's been going for a while but if it's been almost instant that it's happened I would guess it's a battery short. Or maybe that the link wasn't in all the way and it's arced across the contacts, but make sure the battery being shorter isn't the issue first

[dotDominic]

Ok, thanks for the help. Will look into that.

[Eventorizon]

Get some pictures up, it will make diagnosis much easier.

I agree with tony that at first it sounds like a Dead Short, or possibly you have an ESC in backwards or something. Or it could be as simple as the link was dodgy and not up to the usual standard.

[dotDominic]

Ok sure, here are some photos. The circuit as a whole, the individual bits and then the link.
IMG_3684[1].jpgIMG_3693[1].jpgIMG_3695[1].jpgIMG_3703[1].jpgIMG_3710[2].jpgIMG_3716[1].jpgIMG_3720[1].jpgIMG_3723[1].jpg

IMG_3726[2].jpgIMG_3728[1].jpg

Also one of the motors has been making a grinding/crunchy sort of noise when I turn the axle by hand. It also moves a bit less freely, and didn't want to lock up with grub screws as well as the others. Could that be a problem related to this issue? It's still attached to a bulkhead here because I can't get it out without a thinner pair of pliers to grip the axle with.

Thanks.

EDIT 08/03/18: For those reading this in the future, turns out that wiring the fuse on the positive side of the battery, is a more correct way of doing this. So the order should be on the positive side: Battery terminal - link - fuse -*split to parallel*- Led, OR Esc - Motor.

[Pinski1]

I really wouldn't have your remove-able link that way round. Anything could fall on the male pins and short them together activating the robot. Also it looks like you've tied to pull far too much current through the XT60 and it's charred the end. Try using XT90-S with the female end in the robot and the male end as the removable link.

You also need to insulate the soldered terminals of your connectors, insulation tape will work however clear heatshink is best.

[dotDominic]

Hi Pinski, thanks for the response.

I will go ahead and sort out the link, then. I've used coloured heatshrink on everything - I wound a bunch of insulating tape with heatshrink underneath on the link because it was soldered at a 90 degree angle to the connector. The photo with exposed terminals is the link with the heatshrink/insulating tape removed.

[RogueTwoRobots]

I suspect the problem might be that you've wired your speed controllers backwards. The red and black leads coming out one side of your ESCs should go to the battery, and the two black leads coming out the other side should go to your motors.

From what I can see, the rest of the wiring looks okay, so I'd try rectifying the ESCs first then trying again.

[Pinski1]

OH DAMN SON!

Yeh, what Jamie said, man, how did I miss that! the 2 black leads are for the motors, the hint being it doesn't matter which way round the motor is connected. However the power supply into the TZ85A has to be red = +ve battery, black = -ve battery.

I fear you've fried both the TZ85As

[dotDominic]

D'oh! That's a pretty big problem, then! Considering these two didn't smell, sound or look like the other ESC I blew up I think they should be ok. (They'd better be...) While taking these photos I was thinking to myself "There's no way I could've hooked up my ESCs the wrong way! How silly do the roboteers think I am?" ... Uh, yeah, don't answer that question... :P

I'll re do the link anyway since that is definitely busted and I want to make sure it's safe.

Thanks again for the help!

[Pinski1]

It's cool we all make silly mistakes, you make less as you go on, but they still happen and tend to cost more...

[RogueTwoRobots]

While taking these photos I was thinking to myself "There's no way I could've hooked up my ESCs the wrong way! How silly do the roboteers think I am?" ... Uh, yeah, don't answer that question... :P

If it's any consolation, every roboteer will do that, or something similarly d'oh-ish at somepoint in their lives. You're not the first and you certainly won't be the last

If the was no smoke from the ESCs and they don't smell cremated then they may well be fine. Just have to plug them in (right way round this time ) and see.

[dotDominic]

Yeah, thanks guys. When I undertook this project I did realise much of the learning would come from things breaking - but I was expecting that to be in the arena, not before I'd even entered it! :P

[leorcc]

Odds are that your ESC's are still fine. just give them a test (but the right way round this time). Unless you were spinning the motors backwards and forwards by hand (making the motor a generator) there is little that happens. reversing the polarity on the battery side of ESC's is most of the time the culprit for ESC's breaking (next to capacitors breaking off).