Hi & Dasmikro 2s6A issue

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greeno76
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Hi & Dasmikro 2s6A issue

Post by greeno76 » Tue Oct 15, 2019 11:31 am

Hi,

My first post here so please be patient. I've been following a number of forum threads on some of the fantastic builds on this site which has inspired me, along with the kids, to try to build a basic Antweight robot.

I've got hold of the various components below and wired them up as shown in the pictures. However, I don't seem to be getting any output at the motors.
As a test I've tried a different RX with the same results. I've tried all the various combinations of channels. I've also validated that the RX is bound and working by plugging-in a separate servo directly into the RX.

I've noticed that when no signal is present, the motors will randomly twitch and turn so there's some kind of output there until such time as it is connected to the Rx/Tx.
Does anyone have any advice or tests that I can run in order to work out what's going on?

Many thanks!

Jason

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Kyro
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Re: Hi & Dasmikro 2s6A issue

Post by Kyro » Tue Oct 15, 2019 11:52 am

my advice is steer clear of dasmikro. they are too unreliable/hit and miss as to whether you will receive one that works.

another cheap option that i find great success with is the Chinese 2-3s 5a dual bidirectional esc.

https://www.ebay.co.uk/itm/Dual-Way-Bid ... SwZl5db43x

they have recently made a slightly smaller 1.8a variant

https://www.ebay.co.uk/itm/1-8AX2-Dual- ... 1819354334

i have used both of these and not had any issues with either


please note, the 5a version i have used since i entered into this hobby, with the 1.8a version being used for only 2 months.

but both have performed as expected and i have yet to have one die.

there are smaller lighter alternatives, but these come at a cost. these, in my opinion, are the best bang for your buck.
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MarkR
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Re: Hi & Dasmikro 2s6A issue

Post by MarkR » Tue Oct 15, 2019 12:55 pm

Unless you have an oscilloscope, it may be tricky.

If you can monitor the PWM outputs from the rx, you can see whether the pulse lengths are consistent. With the sticks centred (depending on how you've got it set up), then pulses should be absolutely the same length the whole time, and it should be possible to set it into the "dead zone", maybe using the trim on the transmitter.

If, on the other hand, the pulses are somewhat jittery themselves, I'd expect the behaviour you're describing, and that might indicate a faulty rx or tx.

Do you have any spare servos? Can you try connecting a servo to the same channel, to see if it jitters too?
Robots: Betsie - RaspberryPi controlled flipper bot with gyro stablisation - too clever for her own good?
Stacie - tidy flipper; 4wd driven by hair bands

greeno76
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Joined: Tue Oct 01, 2019 9:41 pm

Re: Hi & Dasmikro 2s6A issue

Post by greeno76 » Tue Oct 15, 2019 4:04 pm

Kyro wrote:
Tue Oct 15, 2019 11:52 am
my advice is steer clear of dasmikro. they are too unreliable/hit and miss as to whether you will receive one that works.
Noted, thanks for the info. If I can't diagnose this issue reasonably quickly I'll try the options you suggest.
MarkR wrote:
Tue Oct 15, 2019 12:55 pm
Unless you have an oscilloscope, it may be tricky.

If you can monitor the PWM outputs from the rx, you can see whether the pulse lengths are consistent. With the sticks centred (depending on how you've got it set up), then pulses should be absolutely the same length the whole time, and it should be possible to set it into the "dead zone", maybe using the trim on the transmitter.

If, on the other hand, the pulses are somewhat jittery themselves, I'd expect the behaviour you're describing, and that might indicate a faulty rx or tx.

Do you have any spare servos? Can you try connecting a servo to the same channel, to see if it jitters too?
Thanks for this. I'll see if I can get some sense out the PWM signal, although my oscilloscope is equally shonky!

I did connect a servo to the Tx/Rx combo. It seemed ok but I'll double check as I was only monitoring for movement at the time. I'll run some further tests and report my findings!

Much appreciated, both.

J

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LimaHotel
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Re: Hi & Dasmikro 2s6A issue

Post by LimaHotel » Tue Oct 15, 2019 10:15 pm

Can I ask if that dasmikro has mixing? Coz I've never had one that comes mixed work (out of 3), whereas my unmixed ones have all worked (out of 6). That doesn't mean they're a good choice though, as only one was totally weird error / behaviour free, and they are fragile. I recommend bustophedons for value (though they're big/heavy), continuous rotation servo boards if you're only planning 2wd, or a proper robot speed controller like an arc Robotics AWESCv4, or Rory's NanoTwo. I guess a couple of vex29s would also work fine? Though they'd be overkill (like the bustophedons), and don't have a built in bec.
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MarkR
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Re: Hi & Dasmikro 2s6A issue

Post by MarkR » Wed Oct 16, 2019 10:07 am

I only tried one Dasmikro 2s6a - without mixing - it worked ok for a while until I managed to let the magic smoke out. I wasn't convinced that getting more was a good idea, so I didn't.

It didn't seem to be a problem as a speed controller, it's just the mechanical construction I don't like - too easy to create shorts and break tracks off.

After that I designed my own ESCs, they all have pin-through-hole connections for everything used in the robot.
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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