Mark's Antweight build

All things antweight

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Paulmchurd
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Re: Mark's Antweight build

Post by Paulmchurd »

Atleast nothing blew up!

I found another nice looking h-bridge. The dasmikro seems to have been taken off banggood.

https://m.ebay.co.uk/itm/Stepper-Dual-M ... =547517332
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MarkR
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Re: Mark's Antweight build

Post by MarkR »

That H-bridge looks very tidy.I like the extreme low profile and that it's official rated to work with 3v3 logic levels. also benefits from actual holes in the PCB, unlike the Dasmikro which is compact but fiddly.

I could use one of those for weapon control.
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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peterwaller
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Re: Mark's Antweight build

Post by peterwaller »

I used those chips in my previous speed controller board I used one chip for each motor if you parallel the two drivers in each chip you get 2.4 Amp drive. The main problem using the chip direct was the are fairly large with 24 pins on a very narrow spacing so difficult to solder. The MX612 are much smaller with only 8 pins although they are limited to 9.6 v.
Paulmchurd
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Re: Mark's Antweight build

Post by Paulmchurd »

Wouldnt using two of the chips be far to much for an antweight? When only 1 is needed.

I've ordered one off banggood. Cheaper then the one I posted. I'll give it a test and report back ... in a few weeks
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peterwaller
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Re: Mark's Antweight build

Post by peterwaller »

Back when that controller was designed some of us were using the pololu high power motors which had a stall current of 1.6 amps at 6 v.
So if you were running them on 8.4 v that's 2.2 amps and even higher on 3 cells hence the doubling up.
Paulmchurd
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Re: Mark's Antweight build

Post by Paulmchurd »

Ahhh ok, is there a way to work out the stall currant other then putting a multimeter in a series and grabbing the wheels?

These n20 motors seem like a lucky dip.
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peterwaller
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Re: Mark's Antweight build

Post by peterwaller »

That's as good a way as any if they don't quote it.
Apart from the ones I mentioned and a couple of 12v ones they are nearly all sub 500ma so should be OK.
See chart from my web site of the ones I have found.
http://www.antweightwars.co.uk/MotorSpecs2.pdf
Ant Ipodean
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Re: Mark's Antweight build

Post by Ant Ipodean »

I like the look of that TB6612 board, but can it be connected directly to the PWM outputs from an RC Rx, or would there need to be some additional "circuitry"?
And if so, is it very complicated to set up?

Mike.
Paulmchurd
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Re: Mark's Antweight build

Post by Paulmchurd »

You need to use a micro controller such as an Arduino or raspberry PI to act as the speed controller.

Someone correct me if I’m wrong.

An electronic speed controller contains a h-bridge, BAttery eliminator circuit and a micro controller. The controller converts the Tx/Rx PWM to a readable pwm by the h-bridge which then controls the direction and speed of the motors using switch’s.

These h-bridges are for people who are making their own ESC’s. Eventually with tinkering around with creating your own. You can buy all the individual components and produce your own Esc circuit board just like the ones on nuts and bots shop.

I’ve self taught myself by watching YouTube and reading website tutorials. It can be a little tricky to understand at first but once you get the hang of programming/connecting the circuit boards together it get easier. It’s been a lot of fun tbh learning how to make an ESC.

Here is a video of how to use the h-bridge.

https://youtu.be/u0Ft8SB3pkw
Ant Ipodean
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Re: Mark's Antweight build

Post by Ant Ipodean »

Thanks for that link.
It just seems that an Arduino or raspberry pi board has far more functionality than is actually needed to link an RC Rx to an H bridge just to control 2 motors, so costs too much in terms of space and weight.
Providing the 5 volt supply is easy enough, but I wonder if the "micro controller" function just requires one or two resistors or capacitors, or is it more complex than that?
Mike.
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