Some 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!
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.
LED
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
24
22
15
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.
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.
Not 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.
This is something I’ve really been waiting for … a link between a Raspberry Pi and a mobile phone app.
Bluedot consists of two parts – an App and some Python code which runs on the Raspberry Pi. I used a Raspberry Pi Zero W, which is a handy combination of small size and built-in WiFi and Bluetooth.
Setting up Bluedot is easy – just follow the instructions and download the App from the Google App store.
Bluetooth controlled belt
I’ve been using Bluedot to demonstrate some work for e-Textiles at school. It’s my intention to combine a small Raspberry Pi and power pack into something that can provide a range of patterns and colours controlled from a smart phone. Bluedot has enabled this to happen easily.
Now, here’s where I show my ignorance of Python terminology and correct use of syntax.
As I see it, Bluedot’s documentation points to the library receiving the events and then calling functions depending on what’s been pressed on the smart-phone’s screen.
I wanted to see whether it was possible to display patterns in a background loop and then change these. When I’m doing this with a microcontroller such as the Picaxe, I’d have a main loop reading a variable, in which I had stored the current “state”. The state would be used to trigger different patterns of outputs. Some where in the main loop I would poll the inputs to see if there’s a change – if there is, I’d change the state variable to a new value. I wasn’t sure if this is the right thing to do within Python, but it has worked for me for at least two hours.
PiZero controller in 3d printed case.
My demonstration “belt”, which is currently adorning a mannekin, has 34 NeoPixel (WS2812) RGB LEDs connected to a long servo cable. The Pi Zero has a matching connector soldered to the relevant connections and is currently running from a PoundLand USB battery. My program allows the belt colour to be changed to Red, Green, Blue, Purple and random colour sparkles. I’ve used the Pimoroni Unicorn Hat python module to drive the LEDs although I did modify it to allow me to access individual LEDs along the line (Set Single Pixels) rather than relying on figuring out an X/Y matrix.
Overall, I’m pleased. I’m looking forward to some feedback regarding my approach to polling Bluedot rather than relying on events triggering functions. I’m sure there’s a better way but this sort-of suits my understanding as I sit on the fence between different programming languages.
Oh, and by the way, the Glowing Pendant is a ring of LEDs but controlled independently from a Redfern Electronics Crumble Controller.
## Bluetooth control of sparkles ##
from bluedot import BlueDot
from signal import pause
from random import randint
import time
import unicornhat as unicorn
ledno = 34
dim = 150
mode = 0
print("Bluedot Sparkles")
unicorn.set_layout(unicorn.AUTO)
unicorn.rotation(0)
unicorn.brightness(1)
width,height=unicorn.get_shape()
def scroll():
for led in range(ledno):
unicorn.setsingle(led,0,0,255)
unicorn.show()
time.sleep(0.05)
def allred():
led = randint(0,ledno)
red = 255
unicorn.setsingle(led,red,0,0)
unicorn.show()
time.sleep(0.1)
unicorn.setsingle(led,dim,0,0)
unicorn.show()
time.sleep(0.1)
def allgreen():
led = randint(0,ledno)
green = 255
unicorn.setsingle(led,0,green,0)
unicorn.show()
time.sleep(0.1)
unicorn.setsingle(led,0,dim,0)
unicorn.show()
time.sleep(0.1)
def allblue():
led = randint(0,ledno)
blue = 255
unicorn.setsingle(led,0,0,blue)
unicorn.show()
time.sleep(0.1)
unicorn.setsingle(led,0,0,dim)
unicorn.show()
time.sleep(0.1)
def allpurple():
led = randint(0,ledno)
red = 255
blue = 255
unicorn.setsingle(led,red,0,blue)
unicorn.show()
time.sleep(0.1)
unicorn.setsingle(led,dim,0,dim)
unicorn.show()
time.sleep(0.1)
def alloff():
for led in range(ledno):
unicorn.set_pixel(led,0,0,0,0)
unicorn.set_pixel(led,1,0,0,0)
unicorn.show()
def randomsparkle():
x = randint(0, (width-1))
y = randint(0, (height-1))
r = randint(0,2)*127
g = randint(0,2)*127
b = randint(0,2)*127
unicorn.set_pixel(x, y, r, g, b)
unicorn.show()
time.sleep(0.1)
def dpad(pos):
global mode
if pos.top:
alloff()
print("up")
mode = 1
elif pos.bottom:
alloff()
print("down")
allgreen()
mode = 2
elif pos.left:
alloff()
print("left")
mode = 3
elif pos.right:
alloff()
print("right")
mode = 4
elif pos.middle:
alloff()
mode = 5
print("fire")
print("Starting bluedot")
scroll()
#alloff()
#scroll()
#allred()
#time.sleep(1)
#allblue()
bd = BlueDot()
while True:
bd.when_pressed = dpad
# print(mode)
if mode == 5:
randomsparkle()
if mode == 1:
allred()
if mode == 2:
allblue()
if mode == 3:
allgreen()
if mode == 4:
allpurple()
pause()
I guess many of us find lighting up loads of LEDs to be rather interesting, so when I saw this group of 4 Matrix displays for sale cheaply, I had to pounce and find a use for them later.
There are a number of methods described for running them with the Raspberry Pi but I stumbled on an excellent library which does all of the hard work. The documentation is comprehensive and the examples really show what is possible.
Matrix Display resting on a Lego compatible case. The sizes fit perfectly, so I guess a construction brick display device is on the way soon!
I started out with just an 8×8 display originally, not trusting that I’d have any success with a larger module, but soon I got bored and upgraded. Woah… this thing works well, especially once the correct rotation had been added.
#!/usr/bin/env python
import time
from random import randrange
import max7219.led as led
from max7219.font import proportional, SINCLAIR_FONT, TINY_FONT, CP437_FONT
import feedparser
python_wiki_rss_url = "http://open.live.bbc.co.uk/weather/feeds/en/2649808/3dayforecast.rss"
# create matrix device
device = led.matrix(cascaded=4)
device.orientation(90)
print("Created device")
while True:
print("Getting feed")
feed = feedparser.parse( python_wiki_rss_url)
for repeats in range(10):
print(repeats)
for items in feed["items"]:
msg = items["title"]
msg = msg[0:msg.find(",")]
print(msg)
device.show_message(msg, font=proportional(SINCLAIR_FONT))
time.sleep(1)
msg = time.asctime()
msg= time.strftime("%H:%M")
print(msg)
device.show_message(msg, font=proportional(SINCLAIR_FONT))
time.sleep(10)
I quickly looked up reading RSS feeds as well as strftime for python, and in a short period of time the program above shows a clock for 10 seconds and then parts of the 3 day forecast.
I’ve already written about using WS2812B RGB LEDs with the Pixel Cushion, but seeing a set of concentric circle PCBs available got me thinking. I originally used these a sort-of Superhero badge as part of a fancy-dress outfit, but they were crudely mounted onto a plastic disk with cable ties.
A bit of work with 3d software and a 3d printer produced this.
I’ve used a servo extension lead to power and control the LEDs. They’re all daisy-chained as before, starting from one of the outside LEDs and finishing on the final LED in the centre. In total, there are 61 LEDs which means that if they were run at full power, the load on the battery would be rather high (60mA per LED * 61 LEDs = 3.66 Amps). However, I’m limiting the maximum value for each LED so that they’re dimmer. An added advantage is that I can still see if I look directly at the LEDs. The overall effect is rather striking, although the camera used in the video above struggled to focus (perhaps macro might have been better) but it’s easy to see the exposure control kicking in as more LEDs are lit.
The Raspberry Pi power connections are fed directly into the GPIO connector, bypassing a somewhat delicate micro-usb port as well as ensuring that large currents for the LEDs are going to the adjacent 5v pin which is then fed out to the pixel rings.
Files for the clip-together case can be found and 3d printed from the: YouMagine Website
I suppose it would be prudent to add some sort of switch to initiate a shutdown routine, but for the moment I’ve been just pulling the plug.
Yesterday’s Raspberry Jam in Exeter gave an opportunity to briefly demonstrate Seq24 on the Raspberry Pi. I’ve got a Pi-TopCEED desktop and inside this is fitted a small amplifier and speaker. It’s a simple addition but gives me a chance to use sound without trailing wires.
Seq24 is a block-based sequencer. Patterns of notes are entered into blocks and each of these can be triggered with either the mouse or keyboard. As an experiment, I’ve entered parts of Pachelbel’s Canon in D into the blocks so that they can be cued one at a time. I’ve chosen Canon as it’s based on a repeating chord pattern of D, A, Bm, F#m, G, D, G, A over 4 bars.
Any Pi is fast enough to run Seq24 is external MIDI gear, but now that I’ve got a Pi 3 I’ve installed QSynth (which can emulate an external polyphonic sound module and uses SoundFonts) as well as AMSynth, which emulates a classic analogue synthesizer. These both seemed pretty easy to set up once I’d found a GM Sound Font for QSynth.
Cueing different parts of the Canon gives an entirely new mix which certainly adds an interesting perspective on the original music. Hopefully a YouTube clip will appear here soon!
Seq24 and two virtual sound generators running on the Pi-TopCEED at Exeter Raspberry Jam.
LED cushion… enough to make your heart skip a beat?
I’ve been experimenting over the Christmas period with WS2812 RGB LEDs. I intend to write up these experiments in another post, but having a bit of free time enabled me to try something a little more ambitious.
Connecting RGB LEDs to the Raspberry Pi has been simplified and they are now supported in ScratchGPIO once the Pimoroni unicornhat software is installed. By wiring together a bunch of these, I was able to create a 25 LED matrix.
Control via ScratchGPIO was a little slower than I needed and in addition I wanted to see if I could write text. I’ve done this in the past using figlet and writing the result to a Minecraft screen as a pile of blocks. It seemed it might be possible. I originally intended to go for a set of 8×8 LEDs (Similar to the Unicorn Hat or the Sense Hat from Pimoroni) but with time running short for a demo, I had to opt for just 5×5. The maths is what stings here… 25 LEDs, 3 pieces of wire between each, two ends to strip, twist and solder = 150 joints. For 8×8 this would be…. well, ouch!
In the video below, I present the results of the first set of experiments. I fully intend to solder up the remaining 39 LEDs to make 8×8, but this will take some time. I’ve mounted the LEDs on cardboard inside the cushion and covered them with bubble wrap. I will eventually use something much softer in the final product.
The controlling program is written in Python and uses a slight modification of the Unicorn Hat module. It took me a little while to find where Python modules are stored but I found it in
Here’s the final program:
#!/usr/bin/env python
import iprpixel as unicorn
import time
import datetime
import random
from mcpi import minecraft
import commands
#print("Here goes")
lookup=[0,1,2,3,4,9,8,7,6,5,10,11,12,13,14,19,18,17,16,15,20,21,22,23,24]
unicorn.brightness(0.6)
#---------------------
#wr_str = raw_input('What would you like to write? ') # ask the user what they'd like to write at the current position
#wr_str = "Hello"
def choosecol():
colval=random.randint(0,5)
global r_val, g_val, b_val
# print "Colour is :",colval
if colval==0: #red
r_val=255
g_val=0
b_val=0
if colval==1: #green
r_val=0
g_val=255
b_val=0
if colval==2: #blue
r_val=0
g_val=0
b_val=255
if colval==3: #orange/yellow
r_val=128
g_val=128
b_val=0
if colval==4: #cyan
r_val=0
g_val=128
b_val=128
if colval==5: #magenta
r_val=128
g_val=0
b_val=128
def sparklefill():
for led in range(400):
ledpos = random.randint(0,24)
r_val = random.randint(64,255)
g_val = random.randint(64,255)
b_val = random.randint(64,255)
unicorn.setapixel(ledpos,r_val,g_val,b_val)
unicorn.show()
time.sleep(.05)
for led in range(400):
ledpos = random.randint(0,24)
unicorn.setapixel(ledpos,0,255,255)
unicorn.show()
time.sleep(.05)
unicorn.setapixel(ledpos,0,0,0)
unicorn.show()
# time.sleep(.05)
def timestring():
global figletstring, list_line
# wr_str= time.strftime('%I:%M %p')
wr_str= "Time Now : "+time.strftime('%I:%M %p')
figletstring=str(wr_str).upper()
cmd = 'figlet -w 400 -f 3x5 '+figletstring # create an operating system command
line = commands.getoutput( cmd ) # send cmd as a command to the operating system and receive the result.
list_line = line.rstrip().split('\n') # split the result from 'figlet' into separate lines (right strip new line feeds)
def ipaddress():
global figletstring, list_line
figletstring = commands.getoutput( "hostname -I" )
# print figletstring
cmd = 'figlet -w 400 -f 3x5 '+figletstring # create an operating system command
line = commands.getoutput( cmd ) # send cmd as a command to the operating system and receive the result.
list_line = line.rstrip().split('\n') # split the result from 'figlet' into separate lines (right strip new line feeds)
def heart1():
global list_line
list_line = [" "," # # ","#####","#####"," ### "," # "]
def heart2():
global list_line
list_line = [" "," "," # # "," ### "," # "," "]
def displayleds():
for startcolumn in range(len(list_line[1])-4):
column = 0
rownumber=-1
time.sleep(0.1)
for row in list_line: # one row at a time from list_line (the result from figlet)
# print row, len(row)
if rownumber>-1 and rownumber<5:
column=0
# print "working with row",row,"completed"
for letter in row[startcolumn:startcolumn+5]: # work along each row - check each character. If it's a '#' then print a block else leave it as air
if letter == "#":
unicorn.setapixel(lookup.index(column+(rownumber*5)),r_val,g_val,b_val)
else:
unicorn.setapixel(lookup.index(column+(rownumber*5)),0,0,0)
column = column+1
unicorn.show()
rownumber=rownumber+1
def boxdraw():
global list_line, r_val, g_val, b_val
for boxes in range(6):
choosecol()
list_line = [" "," "," "," # "," "," "," "]
displayleds()
time.sleep(0.1)
list_line = [" "," "," ### "," # # "," ### "," "]
displayleds()
time.sleep(0.1)
list_line = [" ","#####","# #","# #","# #","#####"]
displayleds()
time.sleep(0.1)
def pacman():
global list_line, r_val, g_val, b_val
r_val=255
g_val=255
b_val=0
for bite in range(6):
list_line = [" "," ### ","#####","#####","#####"," ### "," "]
displayleds()
time.sleep(0.5)
list_line = [" "," ### ","#####","## ","#####"," ### "," "]
displayleds()
time.sleep(0.5)
def smiley():
global list_line, r_val, g_val, b_val
for flashface in range(5):
choosecol()
list_line = [" ","## ##","## ##"," ","# #"," ### "," "]
displayleds()
time.sleep(1)
def spinner():
global list_line, r_val, g_val, b_val
for boxes in range(5):
choosecol()
for spin in range(4):
list_line = [" ","# "," # "," # "," # "," # "]
displayleds()
time.sleep(0.01)
list_line = [" "," # "," # "," # "," # "," # "]
displayleds()
time.sleep(0.01)
list_line = [" "," #"," # "," # "," # ","# "]
displayleds()
time.sleep(0.01)
list_line = [" "," "," ","#####"," "," "]
displayleds()
time.sleep(0.01)
def heartbeat():
global r_val, g_val, b_val
for hearts in range(10):
r_val=255
g_val=0
b_val=0
heart1()
displayleds()
time.sleep(1)
heart2()
displayleds()
time.sleep(0.25)
for displayip in range(5):
choosecol()
boxdraw()
choosecol()
ipaddress()
displayleds()
time.sleep(1)
while True:
# pacman()
smiley()
spinner()
boxdraw()
heartbeat()
choosecol()
timestring()
displayleds()
time.sleep(1)
sparklefill()
I’ve been thinking about this for a while. It’s all very well having a battery pack connected to some motors and LEDs with Lego, but what about making it all controllable remotely from Scratch running on a laptop or desktop?
In previous articles, I’ve looked at using the Raspberry Pi and the Lego firmly next to each other, with a wireless keyboard and mouse and that oh-so-bulky monitor cable.
Then I figured out what the implications of “Scratch Interface Device” meant when I spotted it on CympleCy’s website.
Having bundled the Raspberry Pi into the case and added a set of LEDs and switches, it was a simple job to install SID and get working. The last four digits of the Raspberry Pi are used to identify it, and these must be entered on to the PC (Or Mac, if you have one). Once this is done, starting Scratch and enabling Remote Sensor Connections allows the laptop to control the Raspberry Pi without having the bulky connections. Now it’s possible to seriously integrate Lego and intelligent control.
ScratchCPIO program to run the lighting
The whole setup now runs faster as the Scratch project runs on a PC, while the Raspberry Pi handles the GPIO control remotely. I haven’t yet tried all of the functions, but all those that I’ve tried have been supported. My PiBlox case has space for the Raspberry Pi camera, so running “Broadcast Photo” causes a photograph to be taken and stored on the Pi’s SD card. At the moment, it’s directed to /home/root/photos but maybe that’s something I’ve done wrong – ScratchGPIO running directly sends the files to /home/pi/photos which is a little more convenient (more later on why…).
Now… I could have stopped here, but inspiration has now kicked in. At the time of these early experiments, I was using an external battery pack and then…
…the Raspberry Pi Zero was released!
And the reason I’m now thinking of experimenting further?
Some time ago, I wrote about Bluedot – and now I’ve used this to control the Initio robot.![IMG_20171226_201348727_HDR[1]](https://rpikitchen.files.wordpress.com/2017/12/img_20171226_201348727_hdr1.jpg?w=182&h=243)
My son was fortunate enough to receive a 
![IMG_20170630_094649037_HDR[1]](https://rpikitchen.files.wordpress.com/2017/06/img_20170630_094649037_hdr1.jpg?w=183&h=244)
rPi Kitchen 