MichaelG92's Build Diaries

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Kyro
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Re: MichaelG92's Build Diaries

Post by Kyro »

i can also second that those particular hinges hold up pretty well to combat... the bot shown has one hell of a flip (gave a few bots a flying lesson at our little tournament) and suffered no issues...
although being brass they could possibly bend if it took a big whack from a spinner in the right spot, but for £1.40 a pair, it's well worth picking up a few spares... its better to have them and not need them than to need them and not have them...
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MichaelG92
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Re: MichaelG92's Build Diaries

Post by MichaelG92 »

I didn't have time to write this last week but I competed in my first event (June's Bodgebots event put on by BBB aside) at Roboshowdown last Saturday in Milton Keynes. I had hoped to enter MicroNewton, having taken advantage of Team Panoramic's new commission service, but a problem with the 3D printer meant it wasn't ready in time. Luckily Harry lent me one of his flipper bots, pictured below, so I could still take part.

Image

First up was the 2v2s, for which I was paired up with Toothless. We lost both of our fights so were quickly out of the competition, but it did give me the opportunity to get used to driving a robot; something I had little experience with and it showed!

My first fight in the 1v1s was against The pushbot from Mars. When we first came together I managed to get underneath it so I thought I was in with a chance after all! Unfortunately I was then shoved against the wall, and then a good push from the side saw me end up in the pit.
So into the losers' bracket, and I was up against the powerful flipper of Unorthodox. In an incredibly one sided fight he flipped me four times in about as many seconds, gaining some great air time in the process, and I drove into the pit trying to get away from him. So I was out already having spent a combined total of about twenty five seconds in the arena!

But it wasn't the end of my day, as all robots who were 0-2 got entered into the losers' rumble The Show Must Go On! award. they split us into 3 bouts of 6 with the top two of each going to the final. Unfortunately by this point the spring on the transmitter I'd borrowed had broken, so the driver's stick would no longer centre automatically and it made driving virtually impossible as I would spin around in circles. So I wasn't filled with hope, but I managed to do ok. Because I was mostly spinning around in circles as I tried to drive straight I largely avoided the carnage, and I even managed to immobilise Dusty when I flipped him upside down. By this time others had been immobilised so I went through to the final! In the final I started ok and survived a few hits from the spinners, but the driving problems finally caught me out and I ended up stuck with one wheel over the pit and forgotten about until I fell in myself trying to escape.

I also took part in the gladiator rumble where, again, I did quite well purely because I stayed out of trouble because I couldn't drive. I think I got to the last five before my driving problems led to me reversing into the one remaining pocket of space in the pit again.

To finish off my day I took part in the boss fight against Tom Brewster's beetleweight Drizzle, along with ten others. Sadly I didn't last long at all, as after narrowly avoiding getting whacked by Drizzle's disk I ended up nosediving into the pit for the final time.

Overall it didn't go too badly for a first event; the big thing I need to work on is driving, which I'll practice when the real MicroNewton arrives. I'm also hoping to get a pushbot ArmamAnt! finished in time for Sheffield which I'll be working on over the next month. I've also started making plans for BBB's Halloween bodgebots event in November which I'm really looking forward to. Thanks again to Harry for letting me borrow his robot, it was a great learning curve competiting with it. And I'd like to think I'd returned it in pretty good condition..!
Michael - Team MG Robotics

Fledgling Surrey based roboteering team

Antweights:

MicroNewton - flipper
ArmamAnt! - pusher
GFB - flipper (under construction)
Fight or Flight - flipper (under construction)
MichaelG92
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Location: Surrey

Re: MichaelG92's Build Diaries

Post by MichaelG92 »

I took a day off work today and decided to put ArmamAnt! together for AWS59 in two weeks when my ESC went on fire!!

It was the electronics kit I'd used in my bodgebot from BBB's June event, and it had worked fine. I snipped the wires by the motors,wired up the N20s and they worked fine in testing. It was only after I tried them out after soldering them on that the ESC caught fire, and the photo below is the aftermath:

Image

What did I do wrong? Is the ESC, as I suspect, beyond repair?
Michael - Team MG Robotics

Fledgling Surrey based roboteering team

Antweights:

MicroNewton - flipper
ArmamAnt! - pusher
GFB - flipper (under construction)
Fight or Flight - flipper (under construction)
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Kyro
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Re: MichaelG92's Build Diaries

Post by Kyro »

id say the esc is kaput...

you can always try it and see if it has any life... maybe the second channel still works and you can use it to power some sort of brushed weapon...

im impressed though, i have used many of these esc's and never had one pop...
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MarkR
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Re: MichaelG92's Build Diaries

Post by MarkR »

If you know what chip it is, then it looks replaceable, if no tracks on the board are damaged. The problem I always had with Dasmikros was the tracks lifting and making a short.

Personally I'd suspect a short circuit somewhere. If your motors aren't shorted now, perhaps they were briefly during your test?

Do you have a multimeter handy? A bench supply?

I usually try out my dodgy (home made) ESCs on the bench supply with a low current limit set, before I connect them to a lipo (easy to say with hindsight!).

Did the magic smoke escape immediately on power on, or after the radio was activated?

Does the 5v regulator still give 5v? Does the rx still flash its lights?
Robots: Betsie - RaspberryPi controlled flipper bot with gyro stablisation - too clever for her own good?
Stacie - tidy flipper; 4wd driven by hair bands
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GeorgeR
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Re: MichaelG92's Build Diaries

Post by GeorgeR »

I'm pretty sure the damaged chip is one of the motor drivers, so I'd suspect a short on the motor wires. Either the two unused motor wires touched momentarily, or maybe it's shorted at the bottom left motor (with 4 wires attached).
Team Zero - AWS 58 Champion!
Zero - rambot - - Axiom - axebot - - Valkyrie - drum spinner
Blueprint - rambot - - Vampire - horizontal spinner - - Particle - ???
RBMK - quad spinner gyro walker - - Duality - dual spinner gyro walker
MichaelG92
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Re: MichaelG92's Build Diaries

Post by MichaelG92 »

Sorry for the late replies, I've been at friend's wedding and away from my computer!
Kyro wrote: Fri Sep 06, 2019 11:24 am id say the esc is kaput...

you can always try it and see if it has any life... maybe the second channel still works and you can use it to power some sort of brushed weapon...

im impressed though, i have used many of these esc's and never had one pop...
I might try that, I do have a few spinners planned. Just need to make doubly sure what happened before I plug a battery back in!
MarkR wrote: Fri Sep 06, 2019 11:50 am If you know what chip it is, then it looks replaceable, if no tracks on the board are damaged. The problem I always had with Dasmikros was the tracks lifting and making a short.

Personally I'd suspect a short circuit somewhere. If your motors aren't shorted now, perhaps they were briefly during your test?

Do you have a multimeter handy? A bench supply?

I usually try out my dodgy (home made) ESCs on the bench supply with a low current limit set, before I connect them to a lipo (easy to say with hindsight!).

Did the magic smoke escape immediately on power on, or after the radio was activated?

Does the 5v regulator still give 5v? Does the rx still flash its lights?
I do think it might be a short circuit. I was holding the two motors in the same hand but I could've sworn they were far enough apart. And they did only start smoking after the radio was activated. What bits would need to touch for a short circuit to occur?

I'm sure my dad does have a multimeter, but I don't know where and he's got more important things to worry about than finding it! So I don't have one to hand, what would I need to test? I've never used one before.
GeorgeR wrote: Sat Sep 07, 2019 6:37 am I'm pretty sure the damaged chip is one of the motor drivers, so I'd suspect a short on the motor wires. Either the two unused motor wires touched momentarily, or maybe it's shorted at the bottom left motor (with 4 wires attached).
Which wires would need to touch for a short circuit? Red touching black?

I do have other speed controllers, but I'd rather not burn out another one for obvious reasons.
Michael - Team MG Robotics

Fledgling Surrey based roboteering team

Antweights:

MicroNewton - flipper
ArmamAnt! - pusher
GFB - flipper (under construction)
Fight or Flight - flipper (under construction)
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MarkR
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Re: MichaelG92's Build Diaries

Post by MarkR »

red touching black=bad.

The easiest test to do on a multimeter, is to measure the resistance. If it's an "auto range" meter, then you need to understand the display, if not, set it to the correct range, which will be something like 100 Ohms.

A N20 motor will typically have, when not moving, between about 6 and 12 ohms of resistance. If the circuit reads lower than that, it's a short circuit. If it reads higher, it's an open circuit (bad connection). A short circuit might break your ESC, but an open circuit won't.

If you connect two motors in parallel, as you appear to have done - it's ok and normal for 4wd e.g. pushers. Then consider that the resistance should be half, e.g. 3-6 ohms.

Test the multimeter on the resistance setting first, by just shorting the leads and it should read (close to) 0 ohms.

Don't measure resistance with the power on.

You can also check the resistance across the battery terminals with power off, that should probably read high (> 1k ohm), if it's low, then it's probably a short.

Also consider getting a bench supply, or joining a hackspace which has one. It will save your ESC, if you connect a bench supply with current limit, it will (probably) turn off if there's too many amps before everything burns.
Robots: Betsie - RaspberryPi controlled flipper bot with gyro stablisation - too clever for her own good?
Stacie - tidy flipper; 4wd driven by hair bands
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GeorgeR
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Re: MichaelG92's Build Diaries

Post by GeorgeR »

MichaelG92 wrote: Sun Sep 08, 2019 7:23 pm Which wires would need to touch for a short circuit? Red touching black?
Yep, specifically I was referring to the red and black wires that aren't connected to anything in the above picture, if they touched it could burn out the driver chip. In future it's good practice to tape over bare disconnected wires so they can't short against anything.
Team Zero - AWS 58 Champion!
Zero - rambot - - Axiom - axebot - - Valkyrie - drum spinner
Blueprint - rambot - - Vampire - horizontal spinner - - Particle - ???
RBMK - quad spinner gyro walker - - Duality - dual spinner gyro walker
MichaelG92
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Location: Surrey

Re: MichaelG92's Build Diaries

Post by MichaelG92 »

Sorry for the slow response, work is hectic right now...

Ok, thanks all! Taping down motors and spare wires whilst testing sounds like a very good idea, I'll start doing that from now on. I don't have time to work on ArmamAnt! before Sheffield so it definitely won't be competing, but I'll bring it up with me and work on it between fights. And I'll have somebody who knows what they're doing to help me if I mess up again...!

In other news MicroNewton is finally ready thanks to the commissions service provided by Harry at Team Panoramic. I'm quite pleased with how it's turned out and can't wait to try it out myself!

Image

Image

Image
Michael - Team MG Robotics

Fledgling Surrey based roboteering team

Antweights:

MicroNewton - flipper
ArmamAnt! - pusher
GFB - flipper (under construction)
Fight or Flight - flipper (under construction)
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