T_Y's Build Log

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Paulmchurd
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Re: T_Y's Build Log

Post by Paulmchurd »

It’s a lot cheaper to build an arduino speed controller. You can see on my build diary how I did it and the price. I’m happy to show you how to do it if you wanted to meet up again? I’ve been using 4 differnt speed controllers. Except the nano 2... as I don’t have a dsmx Tx.

Issue is the sheer farce of soldering and wiring it all together to fine out you soldered something wrong/a solder pad comes off.
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DieGracefullyRobotics
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Re: T_Y's Build Log

Post by DieGracefullyRobotics »

The Nanotwo does DSM2 and DSMX
Dave
Die Gracefully Robotics - Barely Even a Proper Team.
T_Y
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Re: T_Y's Build Log

Post by T_Y »

An Arduino controller sounds like an interesting project to do! I'm wondering if it's possible to connect a normal receiver's signal wires to the IO pins on the Arduino instead of using the NRF24LO1, so I can just use the transmitter I've already got instead of custom building one.
Thomas - Approximation Robotics AKA "the one that does the mechanums"

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Paulmchurd
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Re: T_Y's Build Log

Post by Paulmchurd »

T_Y wrote: Tue Jun 12, 2018 9:42 am An Arduino controller sounds like an interesting project to do! I'm wondering if it's possible to connect a normal receiver's signal wires to the IO pins on the Arduino instead of using the NRF24LO1, so I can just use the transmitter I've already got instead of custom building one.
Yes you can, it's actually better to do it that way then use the arduino transiever modules.

There is a pretty good video on it via sparkfun. However you need to use the same H-bridge they do. Which uses a lot of I/O. There are better h-bridges.

If your interested in setting one up. I can email you all the code I've used. Or we could arrange a meet up and I can show you/battle test our bots.
T_Y
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Re: T_Y's Build Log

Post by T_Y »

Those Sparkfun videos are quite handy! It looks like that code can be adapted fairly easily to work with other H-bridges, the logic for interpreting the signals should be similar I would guess.

A meetup sounds good, looking at bots that other people have put together would be interesting, plus getting some more driving experience would help!
Thomas - Approximation Robotics AKA "the one that does the mechanums"

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Re: T_Y's Build Log

Post by T_Y »

I've been printing off and cutting parts for Hello, World! Put the shell together and 'borrowed' electronics from Percussive Maintenance while I wait for the Arduino and co. to be delivered. I printed off a load of different length pieces to test out, this is the 'best' I've managed so far:

https://youtu.be/QTx7x1HFgf8

Observations I've had about this setup:
  • The flip is quite fast.
  • Rudder-firing the weapon allows for a fire/retract in one stroke of the rudder control, depending on the length of the link arms between the motor and the flipper. Could be useful if you don't want to expose your flipper/insides to an attack?
  • It's not the most powerful of flips. While it can shift 150g (the block of electrical tape taped together), it does struggle a bit, and it can't lift itself when it is inverted.
I'm currently printing off more different shaped/length parts to fiddle around a bit more to see if I can get more power out of the flip. I'm also wondering if reducing the speed of the motor might make it more powerful?

Also, I managed to discharge a cell in one of my LiPos below 3V, which means it's basically dead now, right? How should I dispose of it?
Thomas - Approximation Robotics AKA "the one that does the mechanums"

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Dazmund
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Re: T_Y's Build Log

Post by Dazmund »

Hello World! looks absolutely gorgeous. I always wanted to build a front-hinge flipper (or a Lightning-esque side flipper) once I finished my other antweight (still have to do better soldering on it), and this is what I wanted it to look similar to!

The use of a motor to power the weapon is unusual though. I've seen it used for axes and the like. Not sure if it has the torque or lift than a good quality servo but I'm not an expert.
T_Y
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Re: T_Y's Build Log

Post by T_Y »

Front hinged flippers are probably my favourite weapon (go Firestorm!). I do have a servo but it's larger and slower than a gear motor, and I had some spare gear motors lying around. To be fair, I just wanted to experiment a bit!
Thomas - Approximation Robotics AKA "the one that does the mechanums"

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Re: T_Y's Build Log

Post by T_Y »

The Arduino arrived, so I've been tinkering around with it over the weekend.

https://www.youtube.com/watch?v=DyEzU7FPGTc

The code is based on Sparkfun's videos on RC control. I modified the code to work with my motor driver, which does not have a separate PWM channel to control speed for each motor, instead it accepts PWM directly on the input channels. I've also added a failsafe so that the motors stop turning if connection to the transmitter is lost (the built-in LED will light indicates a connection).

I still need to wire up the rudder channel to control another motor so I can power a motor-based weapon. Once that's done, I need to reduce the profile so that I can fit it inside a bot. I think I've made an error in this regard by soldering all of the pin headers, it's going to be difficult to remove them! It's probably easier to just get another set of components and hard-solder those instead of trying to de-solder everything seeing as the setup is cheap, might not arrive in time for AWS though.

The setup costs around £12, around £4 each for the Arduino Pro Mini, 2 motor driver and the single motor driver (once it's wired up). I used this dual channel motor driver for drive and will be using this single channel motor driver for the weapon.
Thomas - Approximation Robotics AKA "the one that does the mechanums"

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Ant Ipodean
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Re: T_Y's Build Log

Post by Ant Ipodean »

A tip I figured out, when removing/desoldering multiple header pins ..
Carefully prise the plastic pin holder off first, then desolder and remove the pins individually.

Mike.
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