Minecraft Molehills?

Here’s a little program for generating random holes in the landscape and automatically putting a candle at the bottom. The idea is that this could be run on the Raspberry Pi running as a server so that other players can have a little fun hunting for them.

I’ve discovered that candles don’t like being put underwater… no surprise there!

Hole generated in Python with a candle at the bottom.

Watch your step – a deep hole created by the python program.

Screenshots have been created following the instructions at Raspberry Pi – Spy.

from mcpi import minecraft
import time
import random
mc = minecraft.Minecraft.create()

mc.postToChat("Python is now in control!")

def Molehole(x,y,z,depth):
    mc.setBlocks(x,y+40,z,x+0,y-depth,z+0,0) #clear the space first
    mc.setBlock(x,y-depth,z,50) #Put a candle at the bottom of the tunnel  

for loop in range(20):
    startx = random.randint(-120,120)
    startz = random.randint(-120,120)
    starty = 0

RPi Kitchen elsewhere…

I’m very keen to make resources available, so here are links to the other sites. They’re not all Raspberry Pi related, but they do include programming, 3d design, hacking, modifying and making:

YouMagine – for my 3d printing and other design files.

YouTube – for my videos of models, programming ideas and demonstrations.

Poundland Universal Remote Control

I’ve been experimenting with the infra-red input commands on the PICAXE for some simple remote control Lego robots. There is an official remote control for the PICAXE – in an eye-catching blue case, but for economy I’ve bought a bunch of Poundland universal remote controls.

They don’t give the same hardwearing impression that the official ones give – the cases are a little more flimsy, but they do seem more than adequate to remote control a PICAXE and can therefore add a whole new dimension to PICAXE circuits. An infra-red receiver is an easy thing to add and it means that one input can effectively pretend to be many switches – all present remotely on the handset.

To program the remote, press and hold the TV remote for 5 seconds. The LED will light at this point. Type in the code 0495. When this is completed, the LED will go out and the remote is ready to use.

The command to receive the remote signals is to use:

irin [100],3,b0

Assuming that you’re using input 3. I often use the 08M2 Picaxe, and this is fine. The value is dumped into byte variable b0.

Often I use the following program:

    irin [100],3,b0
    goto main

to see the effect of pressing different buttons in the debug window.

I’ve discovered the following codes  (File: PoundlandUniversalRemote as a PDF file):


Bluedot – Bluetooth and the 4-tronix Initio Robot.

IMG_1595Some time ago, I wrote about Bluedot – and now I’ve used this to control the Initio robot.

Bluedot consists of two parts – an App and some Python code which runs on the Raspberry Pi. The Initio takes a variety of Raspberry Pi’s, but I recently received some PTFA funding to upgrade to a Pi3 for the club robot so that it would more effectively run Scratch.

Setting up Bluedot is easy – I then took the demonstration program from the Bluedot website and added GPIO commands into the mix.

While my preference is to have robots running autonomously, using sensors to find their way around (And the Initio certainly excels at this), having an App control the motors is certainly fun and a very immediate way of creating a remote control vehicle.

From here? Perhaps a Web cam streaming images to a remote monitor… Watch this space!



from bluedot import BlueDot
from signal import pause

import time, RPi.GPIO as GPIO

GPIO.setup(19, GPIO.OUT)
GPIO.setup(21, GPIO.OUT)
GPIO.setup(24, GPIO.OUT)
GPIO.setup(26, GPIO.OUT)

def dpad(pos):
    if pos.top:
        print("Both Forward")
        GPIO.output (26, 1)
        GPIO.output (21, 1)
        GPIO.output (19, 0)
        GPIO.output (24, 0)

    elif pos.bottom:
        GPIO.output (26, 0)
        GPIO.output (21, 0)
        GPIO.output (19, 1)
        GPIO.output (24, 1)

    elif pos.left:
        GPIO.output (26, 1)
        GPIO.output (21, 0)
        GPIO.output (19, 1)
        GPIO.output (24, 0)

    elif pos.right:
        GPIO.output (26, 0)
        GPIO.output (21, 1)

    elif pos.middle:
        GPIO.output (19, 0)
        GPIO.output (21, 0)
        GPIO.output (24, 0)
        GPIO.output (26, 0)

bd = BlueDot()
bd.when_pressed = dpad


Pi-Hut Christmas Tree

IMG_20171226_201348727_HDR[1]My son was fortunate enough to receive a Pi-Hut Christmas tree for an early Christmas present. He’s only eight, so I wanted to supervise his soldering, but I needn’t have worried – the only problem encountered was when I fitted a missing LED, fitted it to the wrong side, removed it and broke the leg. Fortunately, I had a spare lying around in the shed so it was an easy fix.

The Christmas tree is a lovely kit. Gold plating means that the soldering is effortless and the edges have also been guilded for a bit of luxury. The whole board sits rather neatly on top of a Pi Zero W. I’ve been logging in remotely with SSH, but a development I’d like to try is to use BlueDot to remote control it from a phone.

There is a set of instructions for installing the gpiozero software, although I’m unfamiliar with this – I’ve always used rpi.GPIO in the past with good success. One thing I found missing was a map of all of the LEDs. They’re all numbered, but that doesn’t relate to anything on the pin connections. Mapping the outputs (BCM or Board number) was a bit of a mission but I think I’ve succeeded.


Output (BCM)

Output (Pin)

Star 2 3
1 4 7
2 15 10
3 13 33
4 21 40
5 25 22
6 8 24
7 5 29
8 10 15
9 16 36
10 17 11
11 27 13
12 26 37
13 24 18
14 9 21
15 12 32
16 6 31
17 20 38
18 19 35
19 14 8
20 18 12
21 11 23
22 7 26
23 23 16




The next step I’d like to try is to run this from ScratchGPIO, possibly using SID as a starter so that I can run Scratch on a laptop and transfer it over later. For the meantime, I’ve just got a couple of alternative python programs to play with.

All-in-all, this has been a lovely kit that uses loads of outputs on the PiZero. Soldering is effortless and programming with the standard program supplied was easy. One day I’ll read the docs for GPIOzero, but for now, I’ll be teaching with Scratch.

Merry Christmas and a Happy 2018 to everyone!





Using a Raspberry Pi as a desktop PC replacement.

It started with a glass of water… and our old laptop. We probably wouldn’t have used the laptop at all, but it ran Vista which meant that it supported our old-ish Canon Canoscan LiDE scanner. The scanner is, in my view, gorgeous –  it’s light, slim and produces good scans. Sadly, Windows 7 or Windows 10 drivers are unavailable for the scanner. I’m not binning or replacing perfectly good kit, so we’re keeping it!

Unfortunately, a clumsy accident with the glass of water meant that the laptop doesn’t work any more. Just when I needed to do some scanning.

Back in the early days of Raspberry Pi use, I had some minor success with scanning from the command line, but now I know a bit more. I installed XSane, fixed some permissions with the way it handles writing to a folder (can’t remember what, though), and off I went. No problems. The batch mode is especially good for scanning a bunch of photos. 4 at a time and just walk away.

Pi-top CEED

All this was running on my Pi-top CEED. I’d picked this up as a kickstarted and now I’m so pleased with it. I’ve got a wireless keyboard and mouse, and the Raspberry Pi 3 inside really shifts it along well. It boots faster than our Windows 10 laptop and I’m not having to put up with the sound of a fan. It connects with no problem to our NAS and I’ve also managed to pair it with the shared printer.

So, the question remains, what would I install? I’ve got the following, squeezed on to the 8Gb card:

  • CUPS used to connect to a shared printer connected to our laptop. I’ve done this before and found it easier to share than trying to get the now-deceased Vista laptop sharing the printer.
  • XSane to run the scanner. I can scan individual images or a bunch at a time in batch mode.
  • GIMP loads WAY faster on the Pi-top CEED than it does on the Win Laptop. Very useable for the brief experiments I tried.
  • Open Office of course.
  • Seq24 for making music. Runs on my MIDI setup elsewhere in the house, but the Raspberry Pi 3 is also able to run some software synthesizers too. I’ve installed Rosegarden which seems to work well, but I need the time to learn it. It sure looks full-featured.
  • Audacity seems to run well, although I did have it crash once on a file. Not sure what and I didn’t have the chance to try again.
  • Fritzing is a PCB and breadboard design package. Works well and could be handy although I’ve spent so much time in our school’s PCB package that I’m not ready to leave quite yet.

There’s a few other packages that I’m using, but for the most part these are the ones I’ll need for general office-type productivity. My conclusion is that, for me, the Pi-top CEED is an excellent desktop replacement.

I’ll just move the glass of water out of the way…

Game programming in Scratch

xwingpicNot much to write about this time round (seems time is getting even more sparse these days…) but I wanted to post a little game created with my son in Scratch.

Usually, Scratch programming gets put on the back burner – I’ve often got other projects in mind and so I tend to neglect Scratch. This half-term, my son asked for an introduction to programming and so game writing was on the cards. We worked through some simple thoughts and it ended up being inspired by the Star Wars films since he’s quite a fan.

I particularly wanted to show how a simple game can be built up incrementally, starting with simple movement of a space ship and then adding asteroids that have to be dodged. These were given a simple animation of top-to-bottom to give an impression of forward movement.

Once this was working, the detection of hits came in. This was relatively easy – I’m always so impressed at how Scratch offers this as standard, particularly as I’ve tried writing this type of game as a late teenager in Forth on my Jupiter Ace. With that, the nearest one could get was redefining the character set to look like the objects being controlled and then deciding if you’re near enough.

The next stage was to add some kind of missile or torpedo. I know there are a number of ways of solving this but my preferred method was to make the spaceship’s x-position into a global variable (Available to all sprites). This is an excellent introduction to variable types, particularly as we forgot to tick the correct box initially.

A simple game like this is an excellent introduction to programming – it ticks all of the boxes of sequential instructions, conditional branching and iteration, with a generous smattering of local and global variables.

Our little game doesn’t have any custom sound effects, or a timer. These are no real challenge to add.

The final file is available to download for anyone who wants to try it.