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Discussions around autonomous, semi-automatic and intelligent robots and systems.

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Lincoln
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AutoBot

Post by Lincoln » Tue Jan 23, 2018 6:10 pm

Hi, as the name says, i'm now making a autonomous robot. Not for combat of any weight class, just for fun and possibly for showing off at "EM field"
Development on a new pcb is now underway, i'm already a good way towards completing the schematic.

The plan at the moment is to make an automatic robot out of a remote control off road car i have (1/10 scale) but then i will probably make a new version of ManoeuvraBot (about beetle size metal flipper with 3 omni directional wheels) as the new pcb shall have 4 motor drivers each technically capable of 30 Amps, but the pcb probably won't be designed for anywhere near that much current, but the idea is so we can use any motors we find lying around and they should work.
7003314mdrivers.png
7003314mdrivers.png (102.44 KiB) Viewed 249 times
The new board will have connections to a raspberry pi zero, this is because we may use some form of AI and that will need the processing power of a raspberry pi and not the little microcontroller that runs the robot.

I know more details but this post is long enough already. questions welcome, it shows people want to see more updates on this project.
but i will point out this will not be small in any way, i'm designing it to be hand solderable unlike our tiny "SmartBoard" (see details here, http://www.robotwars101.org/forum/viewt ... 0&start=30) so this is kind of a second version of that but it will not be for ants.
Team RobotMad, home of the Smart robots, and very mean pots :)
Chris and Lincoln Barnes

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MarkR
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Re: AutoBot

Post by MarkR » Tue Jan 23, 2018 8:38 pm

That is so cool.

I'm looking at ways of incorporating a Pi Zero into an antweight fighting bot.

My initial plan is to wire it up to the Dasmikro ESC, power it from the Dasmikro's regulator and output PWM signals to drive the main motors. Servos (e.g. weapon) can be driven directly from a Pi's GPIO (in my experience).

I then plan to use a MPU6050 IMU breakout board to provide gyro and accelerometer. I could use a mpu9250 to give magnetometer too, but I've tried it before on a larger robot and get random results, probably because of interference from nearby motors and metal objects on the robot, it's likely to be worse on a smaller robot.

The Pi Zero W of course has built-in wifi and bluetooth, so no separate radio module is needed.

Another option would be the "Motozero" board https://thepihut.com/products/motozero which definitely has enough power to drive two motors (indeed, it will drive four) at modest currents, but unnecessarily large and heavy; I could get a Motozero anyway, it comes as a kit, then discard the bits which aren't needed (huge terminal blocks, IC sockets) and add low profile header to connect to the Pi Zero. But then I need a voltage regulator too.

for larger or autonomous robots I've also been playing with other sensors, the laser ranging time-of-flight modules are so awesome (The http://www.st.com/en/imaging-and-photon ... 53l0x.html VL53L0x ) - and cheap - but tricky to interface with in software.

Another sensor is the optical flow sensor from an optical mouse; I've been trying to hack these too. The pound-shop sells optical mice which actually work. Examining the PCB, it would be moderately easy to remove the unnecessary parts and strip it down to just a sensor with usb interface.

Lincoln
Posts: 115
Joined: Sun Feb 29, 2004 12:00 am
Location: Olney, Milton keynes

Re: AutoBot

Post by Lincoln » Tue Jan 23, 2018 9:31 pm

Nice idea but my first thoughts are that a pi zero is still very big for antwights and quite heavy too.

You should give designing your own pcb a go it's genuinely a good experience and fun if your a nerd and are avoiding doing A level work.
you can then use a microcontroller to do everything necessary for antwights with non of the unnecessary things that come on a pi zero such as hdmi and all that.
i use the mpu9250 but we don't really use the magnetometer except to recognise when the robot is upside down, to thus tell the software to reverse the gyro inputs. The software is the main bit of the time taken in getting a working antwight when you make your own pcb. i don't know if your really a software guy or if the idea of writing software puts you off then probably don't want make your own pcb. disclaimer, my dad writes all the software i do the hardwear.

my new pcb is designed to run without the pi zero w, so even though the pi has wifi and bluetooth im adding my own so that it doesn't always need the pi. the pi is there to explore the possibility of AI.

we have been looking at lidar type sensors but they are all a bit expensive at the moment. so it will probably have IR and ultrasonic sensors instead.
Team RobotMad, home of the Smart robots, and very mean pots :)
Chris and Lincoln Barnes

JeffSergeant
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Re: AutoBot

Post by JeffSergeant » Wed Jan 24, 2018 4:56 pm

Lincoln wrote:
Tue Jan 23, 2018 9:31 pm
You should give designing your own pcb a go it's genuinely a good experience and fun if your a nerd and are avoiding doing A level work.
you can then use a microcontroller to do everything necessary for antwights with non of the unnecessary things that come on a pi zero such as hdmi and all that.
Second that! I designed and got a PCB printed for a bare-bones 'arduino' clone for a little project I did, with no experience and teaching myself I went from a working circuit on a breadboard to a PCB in my hands in a few hours of effort. if you can make something work on a bread-board, then converting it to a PCB is actually pretty straightforward. My trick, was to make a breadboard version of something, transfer it into a PCB design. Then rip apart the breadboard and re-make it based on the PCB schematic, it saved me a lot of bother!

No affiliation, but http://www.ragworm.eu is awesome for low-volume PCB runs; pricier than their Chinese counterparts but they do a free checking service; AND they're in the UK so turnaround is very quick. and 'Eagle' has a free express version for PCB layout; now owned by Autodesk, so the quality is only going to improve, just hope they stick with the freemium model)

Awesome tutorial from Princeton, I didn't use it but wish I had! http://www.princeton.edu/~mae412/HANDOU ... Eagle.html

Lincoln
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Joined: Sun Feb 29, 2004 12:00 am
Location: Olney, Milton keynes

Re: AutoBot

Post by Lincoln » Mon Jan 29, 2018 5:28 pm

just realized that as im using altim's free 'circuit maker' you can easily have a look at my progress on this pcb.
just go to circuit maker, its free. and search for 7003314, and while your there you can look at the smaller version from 2016 7003311
Team RobotMad, home of the Smart robots, and very mean pots :)
Chris and Lincoln Barnes

Lincoln
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Joined: Sun Feb 29, 2004 12:00 am
Location: Olney, Milton keynes

Re: AutoBot

Post by Lincoln » Tue Feb 20, 2018 8:49 pm

decided it's time for another update.

still designing the pcb, but very nearly completed the schematic and have started designing the layout.
here is my draft layout so far, in nice 3d renders.
7003314 draft top-min.png
7003314 draft top-min.png (87.19 KiB) Viewed 82 times
here you can see the Pi Zero W on the left, then along the bottom from left to right is, the programing connector, the combined wifi/bluetooth module, 3.3V output connector, MPU-9250 sparkfun breakout board, micro B usb. up the right hand side are the motor driver outputs. then along the top is: 4 servo connector, 5V out, any (5.5 to 24) V in.
7003314 draft bottom-min.png
7003314 draft bottom-min.png (87.46 KiB) Viewed 82 times
here you can see the motor drivers, 30 Amps each!, and the 2 mosfets for reverse polarity protection.

Our last board was mostly designed by chris (my dad) so this is kinda a personal project and while the software will still be done by my dad, im trying to do the heartware by myself as a learning experience and as something to look good on university applications.

As always, questions are welcome and encouraged.
Team RobotMad, home of the Smart robots, and very mean pots :)
Chris and Lincoln Barnes

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MarkR
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Re: AutoBot

Post by MarkR » Tue Feb 20, 2018 9:37 pm

Right I'm guessing that won't be on an antweight :)

A couple of questions:

* Why do you need a wifi / bluetooth module when the Pi Zero W has those already?
* Why use a breakout board for the mpu9250 when you could just stick the chip directly on your board? It is a qfn package which is possibly hand-solderable?

Lincoln
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Joined: Sun Feb 29, 2004 12:00 am
Location: Olney, Milton keynes

Re: AutoBot

Post by Lincoln » Tue Feb 20, 2018 10:09 pm

Yeah it's 10x7.5cm i did say in the first post this is not for antwights in anyway.

To answer your first question, the pi will only ever be put on if we ever eventually use some form of AI, thus it has its own wifi and bluetooth.
And to your second question, as i'm not that greatly experienced in soldering, very tiny pitch qfn packages are still out of my league, thus a breakout board.
Team RobotMad, home of the Smart robots, and very mean pots :)
Chris and Lincoln Barnes

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MarkR
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Re: AutoBot

Post by MarkR » Tue Feb 20, 2018 11:46 pm

Yeah, looking at a mpu9250 I used on another project, it is fairly small, but probably doable with a steady hand particularly if you have access to a magnifier of some kind. I know some people at Reading Hackspace who can solder such parts. The really problematic components are the ones which don't have pins *at all* - those need to be soldered using an oven and paste.

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