ESC Sanity check

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Wigs
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ESC Sanity check

Post by Wigs » Wed Jul 31, 2019 12:35 pm

Hi,

Another beginners question..

I have bought one of these as I have seen them referred to in the forums a few times as a suitable ESC for Antweights

https://www.ebay.co.uk/itm/401616625711

I was intending to use it to drive 2 motors to get Tank style steering.

However I am confused by the fact that there seems to be only one connector that will go into the receiver.

Can anyone confirm if what I am after is possible with this ESC. (I have tried it with my Saturn Transmitter and Saturn receiver but just got no success. I now have a Lemon Feather and am waiting on a Devo7e from sunny China)

Thank again in advance for any help.

P.S anyone know what the yellow wire is for?

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Ocracoke
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Re: ESC Sanity check

Post by Ocracoke » Wed Jul 31, 2019 12:40 pm

The yellow wire is the second signal wire I believe. The 3 pin connection into the receiver from the ESC will drive the receiver happily but if there are 2x 3pin wires, I imagine the ESC or the receiver would blow. You would need to put the yellow wire into the signal pin on the receiver on the channel you want your steering to be.

When you say no success with just using the one 3-pin connection, do you mean it does nothing? No lights come on in the ESC? Is the 3-pin connection in the right way up?
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MarkR
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Re: ESC Sanity check

Post by MarkR » Wed Jul 31, 2019 3:29 pm

Do you have a multimeter?

If you connect the ESC to the power and nothing else, the red and black wires on the servo-type plug (3-pin dupont connector) should give +5V from the regulator (BEC).

Assuming that's ok, then can you measure the resistance between the various wires (with power off) - the black wires, i.e. ground, should all be connected together, and the signal wires (yellow, white) should give high impedence.

I would agree that the yellow / white are probably the PWM signals for left and right, or possibly throttle / steering if it does tank-mixing.
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Wigs
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Re: ESC Sanity check

Post by Wigs » Wed Jul 31, 2019 8:31 pm

Hi again,

A big thanks to you both, once you had told me the yellow wire was signal only it all seemed to make some sense. Plugged it all in (with much less trepidation) and with some minimal fussing got it all working, wheels, steering, weapon motor :D

Thanks again, I hope I can repay everyone in these forums in kind some time (apart from not trying to trash your robots in battle of course)

Now to get it under 150g.........

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MarkR
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Re: ESC Sanity check

Post by MarkR » Wed Jul 31, 2019 8:38 pm

It does look a little bit on the large side for an antweight ESC, and 5A per channel is definitely excessive, my N20 motors stall at about 0.5A, so even with two stalled in parallel that's still only 1 amp.

I also noticed, on closer inspection of the pictures on various sites, that these ESC have a tiny switch which enables / disables mixing (possibly)? At least, there is an Aliexpress listing which shows what is probably the same model: https://www.aliexpress.com/item/32885834851.html

I can't quite read what H-bridge chip they're using, but it seems it is a DIP-8 so probably has a higher current rating than the surface-mount ones we usually use.

I guess it may be suitable for a beetleweight using the typical motors.
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Kyro
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Re: ESC Sanity check

Post by Kyro » Wed Jul 31, 2019 11:19 pm

i use these esc's or 2x 10a bustophedon in my ants... you are correct, the switch is to enable/disable mixing...

as for overpowered... maybe... but its better to have it and not need it, than to need it and not have it...

the H bridges are marked 7886 EK56DR

the 16 pin chip is STC branded... really hard to see the numbers... hopefully this picture will help...

Image
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MarkR
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Re: ESC Sanity check

Post by MarkR » Thu Aug 01, 2019 10:18 am

Very interesting... it is the RZ7886, the DIP8 version of my favourite rz7899

https://lcsc.com/product-detail/Motor-D ... 28852.html

They should be as tough as old boots, if the other rz chips are anything to go by.
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Kyro
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Re: ESC Sanity check

Post by Kyro » Thu Aug 01, 2019 11:54 am

well, each and every one i have ever purchased is still working perfectly to this day... never had issues with a single one...

id say they are pretty bombproof...

liturally the only issue i have with them is that the wires leave from both ends which can make placement difficult... but that more a design issue than an actual problem...
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MarkR
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Re: ESC Sanity check

Post by MarkR » Thu Aug 01, 2019 12:18 pm

It's very difficult to produce a compact layout which doesn't have wires leaving from several edges of the board.

With power, signal and motors, there have to be quite a few things.

e.g. Dasmikro has awfully tiny nasty pads which are terrible to solder to, but still on both ends.

It's a really good idea to put the motor terminals close to the motor drivers, and the power terminals need to be routed to, basically, everything which is a pain too.

I ended up with one edge for power, one edge motors, and one edge for signals (but mine was also 3x channel)
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Kyro
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Re: ESC Sanity check

Post by Kyro » Thu Aug 01, 2019 12:24 pm

yeah, im sure that this is the most efficient way to put the board together... and its not really an issue... i just meant if I had to say something bad about it, it would be that... but i still happily use them and often recommend them to new builders... for the price and quality, they cannot be beaten in my opinion
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voorsk
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Re: ESC Sanity check

Post by voorsk » Fri Aug 02, 2019 3:18 pm

There appears to be 1.8A versions that're ever so slightly cheaper (than 5A versions from China).

They're using a mixture of images, so who knows what'll actually turn up (I bought one) . :P
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Wigs
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Re: ESC Sanity check

Post by Wigs » Fri Aug 02, 2019 7:24 pm

Nice one,

Please let us know if it's a winner

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