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Pi Wars 2019 Space Invaders (Remote-Controlled)

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Pi Wars 2019 Straight-ish Line Speed Test (Autonomous) Solved, but not very well.

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Pi Wars 2019 The Hubble Telescope Nebula Challenge (Autonomous) solved

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Pi Wars 2019 The Canyons of Mars (Autonomous) solved

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31st March 2019

The PiDER 3.0 Team. Jeff Edwards (left), Me (centre) and Josh Edwards(right)

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31st March 2019

Me with First prize trophy in category, flanked by the two Founders/organisers of the Pi Wars competition, Mike Horne (left) and Tim Richardson (right)

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20th March 2019

Final look under the hood

All the wiring is complete and not likely to change anytime soon. An attachment connector has been added to the rear motor chassis for the extra flashy surprise that I added today. It is totally unnecessary but it looks good :-)

Time to put it all together and begin a period of intensive testing leading up to the competition. There is a couple of minor tweaks to make to the code that I know of, but in general everything is looking quite promising.

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16th March 2019

Colour Calibration

To make things easier for the Nebula challenge colour calibration, I have added some calibration code and extra menu screens so that colour calibration can be performed very quickly on the day. The calibration values are stored in a text file so that the data is persistent when the robot’s power is turned off.

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14th March 2019

5 Barrel Nerf Shooter

This is my solution to firing five projectiles at space invaders. Sorry but the mechanism is secret until the competition, which is why there is a cloth over it. I’m still undecided if I shall leave the mechanism exposed to view or 3D print a cover for it. 

It is planned that a laser pointer will be incorporated to help with aiming the Nerf darts. 

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25th February 2019

Line Following with a Pi Camera

Continuous circular testing. If it didn’t occasionally skew the strips of paper it would go in circles continuously until it's batteries run out. The circle is a bit faceted but it is as curved as I can make it with straight strips of paper.

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Line Following with the Pi Camera.

Testing of my Pi Camera line following code. It’s almost ready for Blast Off now. I keep making minor improvements to the algorithm and no doubt I will do so right up to the competition day. The remote control is my own design as it was the only way I could have a Smart remote that met my specific requirements. It is based around a PIC24 chip. My Library for driving the Nokia 5110 display module using a mbed ARM microcontroller is available here. https://os.mbed.com/users/Fenwiz/code/N_5110_Display/ It can be a good starting point to use one of these displays with other Microcontrollers with only minor modifications.

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23rd February 2019

Sample Holder

I decided to make the ‘Sample Holder’ for the Spirit of Curiosity challenge with my 3D printer. I know it is not essential to do this, but I want to practice driving over bumpy terrain with different size, weight and shape samples to see how likely it is that a sample will be lost on route. Or if my attachment panel is unable to cope with heavy samples.

The Sample holder is printed in two parts and then glued together, enabling the 3mm wire post to easily be made captive within the structure. The 3mm wire is the type that is often used to hold up chain link fencing.

My STL files for 3D printing are available from the Spirit of Curiosity web page.

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21st February 2019

Automatically running your robot’s Python code at boot.

I always use an intermediate bash script to run my Python code because I find it more convenient to modify the location and file name or disable the auto load. This is a quick description of how I have set it up for my PiDER 3.0 robot. You can use this set up, but modify it to your chosen location and file name.

First of all, create a Bash script called ‘RunAtBoot.sh’ and save it in the home folder. You can name it whatever you like but this is what I used. This is the script that it contains. Folder & file names should NOT contain spaces.

#!/bin/sh cd /home/pi/AppDir sudo python scriptname.py &

‘AppDir’ is the directory of your code and ‘scriptname.py’ is the name of your robot’s Python script. Now make the ‘RunAtBoot.sh’ executable. Open the console window and enter the following line.

chmod  +x RunAtBoot.sh

Now using nano in the console, modify the boot profile

sudo nano /etc/profile

Scroll to the bottom of the script and add the following line. Remember to include the ‘&’ at the end to allow the rest of the system processes to run as normal.

/home/pi/RunAtBoot.sh &

Save and close. Now, if you got everything right, the robot code will auto-load every time you boot up. Because the Python runs in the background it is a good idea to have a way of terminating the Robot’s Python script, by means of a combination of buttons pressed together on the controller to free the system resources. You might want to do this to enable a bug fix or colour calibration and then a re-run without the need to reboot. When my Robot’s script terminates, it runs some clean up code before it Exits. Your Python script should do something similar to the following.

output.close()              # Close the RGB array object camera.close()            # Close the Camera object exitScreen()                # Send 'EXIT' message to controller screen GPIO.cleanup()          # Clean up the GPIO exit()                           # Exit the Python interpreter

I hope this will make things easier for other Roboteers to not need a laptop every time to get their Robot operational.

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20th February 2019

Peripherals board tour

Here is a tour of the peripherals board. Now that it is unlikely to undergo any more circuit updates, I thought it might make interesting reading. It is built on a piece of FR2 Matrix Stripboard, 100x160mm -  E013 from CPC. I find this type of board the best and cheapest way of creating one-off circuits, with the advantage over PCB’s for evolution over time.

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20th February 2019

The connector block attachment panel now complete ready for ‘Pi Noon’ and ‘Spirit of Curiosity’ challenges.

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14th February 2019

More testing. The ‘Hubble Telescope Nebula Challenge’ in this picture. This particular arena has took quite a lot of use, as you can see by the rotation area in the centre.

I chose to reverse to the centre each time for the rotate between colours because of the width of the robot. It is easier to avoid running into the walls this way.

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14th February 2019

The Canyons of Mars challenge

If you have enough room to make test arenas for the various challenges, I would recommend you do it as soon as posible and test your robot frequently, even if you are working on different parts of the code. Sometimes fixing bugs for one problem has a knock-on effect somewhere else. It is known as regression testing (re-running previous tests). It is important. Don’t assume that because you tested it once before, it must still be ok. You can never do too much testing :-)