The Challenges

Custom Printed Circuit Boards

One thing that has cropped up each year with our robot has been wiring issues. This comes about due to the modular nature of our bot.

We can swap modules based on the challenge we are doing. This has normally led to needing to swap wires around in a very cramped space.

This year the team have decided to replace as much of the wiering as possible with custom made Printed Circuit Boards (or PCB’s).

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The boards needed some of the components surface Mounted! Keith worked his magic and with the small components mounted we are ready to test them out!

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Fun, The Challenges

Colour Detection using OpenCV

The below clip shows another example of our colour detection script running on the Raspberry Pi.

We have used C++ and Open CV to detect the colour at a certain position in the frame.

The colour is then show in the top left corner of the video.

This will also be shown on a tiny OLED screen on the body of the robot.

 

 

 

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models, The Challenges

Nerf and back again!

Since our robot base is staying much the same as last years, we have been working on modules that can be switched for each competition.
We need our robot to hold and fire Nerf Darts.

Our excellent team engineer has been working his magic with a 3d printer and a lot of patience to create us just what we need!

Above you can see the 3d rendering of our robot and mount. Below you can see a time-lapse of the mount being printed

This will allow us to hold a standard Nerf Dart Cartridge and fire the darts on command.

The finished mount!

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Fun, lessons, The Challenges

Somewhere Over the Rainbow – Colour Detection

One of this years challenges is to detect  some coloured balls from a distance and visit them.

The full details are here. http://piwars.org/2018-competition/challenges/somewhere-over-the-rainbow/

For our robot we are using a Raspberry Pi Camera and OpenCV to detect the colours and some code written in C++.

You can see a video of our robot doing some colour detection below.

Whilst testing this we have come unstuck with the detection when it is dark or when somebody (Vince) in a very red coat walks into the frame of the camera and it detects him and not the ball.

We are planning on using a 2 times lens to bring the balls into a better focus.

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lessons, models

Modelling lessons

Keith has been using Fusion360 for a while now, in fact, he first used it back in 2015 to design the second Ipswich Makerspace PiWars robot as shown below.

Piwars 2015 entry render PiWars 2015 entry render

 

 

 

 

Along the way Keith has learned many lessons, some lessons have been fundamental, as an example the model the renders above were taken from are so broken that they are now unusable.  Towards the end of production for this robot in 2015, Keith was struggling so much with the model that the physical robot only existing one week prior to the competition.  These days Keith is far more competent with Fusion360, but he is still learning lessons.

Recently for the PiWars 4 (2018) competition Keith was designing a mount for a Nerf gun, which included a servo for the trigger mechanism.  Because Servos are common on robots, Keith created a servo model which he could then insert into many different models, or the same model many times.  This is what the model looks like.

Servo without wiresOnce inserted into the main model it looks like this, lovely isn’t it.

So lovely in fact, that Keith printed it, it came out very nice. What do you think?

3D printed servo mountWith much enthusiasm Keith went to mount the servo, here is where he hit the problem, and it is a problem he has had in the past, so he really should have known better.  This is the problem.

Oops, servos have wiresYes, you’ve got it, there is no opening for the wires.  Having done this one too many times now, Keith decided to do something about it.  He updated is master servo model to include the wires and this is what it looks like now.

Servo with wiresSo no more will Keith forget to create openings for the servo wires.  The mount has now been updated and is waiting to be printed.

Modified servo mount

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Fun, The Challenges

Nerf Assembly – 3D Render

Keith has been working with a tool called “Fusion360” to create the 3d models for our robot. This can then create the 3d printing file as well as laser cutter instructions. However – one other feature is that it allows you to create an animation of the 3d object!

This video shows our Nerf mount!

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Nerf Gun mounted to robot No comments
The Challenges

Nerf gun mount

Keith has been doing some more model work in Fusion360 (not on the cat walk!) So far he has the guts of the Nerf gun launch system and magazine modelled, and work has started on the mount system.  Over the next few weeks hopefully he will get this finished and we can get the parts cut and printed and trial fit them to the bot.

Nerf Gun mounted to robot

Nerf Gun mounted to robot

Nerf gun mount

Nerf gun mount, viewed from below

Nerf Gun mounted to robot

Nerf Gun mounted to robot

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The Challenges

OpenCV object tracking

Last week Phil was playing around with object tracking.  So far he can identify colour objects and track the centre.  Phil produced a quick video showing how a red skittle (from last years PiWars skittles challenge) can be tracked and traced on screen.  This looks like a good start, now just need to get the robot to follow it.

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Cheap power supply No comments
The Challenges

Power supply and motors

Keith has been playing about with a new cheap power supply using the Nerf Gun motors as a test bed.  It turns out power supplies are quite a good method for determining how much current they draw and thus what current the motor driver needs to deal with.  Keith produced a quick video demonstrating the power supply with examples using the Nerf Gun motors.

If you are still deciding on motor drivers he recommends getting the motors first and doing a simple stall test with a power supply or multimeter and then getting the motor driver to suit.

See his video here:

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