Paul's Mutterings and Meanderings: Raspberry Pi

Showing posts with label Raspberry Pi. Show all posts

Sunday, 24 September 2023

The ProgPod Mini

I'm one of these people that needs some music or some sort of sounds playing to get me to sleep. I can sleep through music, a thunderstorm, heavy winds. But a dripping tap, someone snoring or even heavy breathing and I'm wide awake.

I wanted an mp3 player that I could easily drag and drop music onto, some of the discontinued Apple device were great for this even though you had to use iTunes. I wanted a Windows share I could use and so my Pipod Mini-ish was born.

I put together a Raspberry Pi zero, a set of bluetooth earbuds, an SD card, a plastic box, 4 PCB mount switches, some vero board and a few bits of wire. On top of this there's a small board that acts as the psu and of course some hot glue. It's not pretty but it does work.

The physical side is up to you, a 3d printer could come up with quite a nice case and you could look at adding a display too. For this, I wasn't bothered as battery life was important.

When you set the Pi up for the first time with raspi-config set your user to auto login at the console.

First off, get some software installed.

sudo apt update
sudo apt upgrade
sudo apt-get install pulseaudio pulseaudio-module-bluetooth mpg123 mc samba samba-common bluez-tools

Add your user to bluetooth
sudo usermod -G bluetooth -a username

And now time for a restart
sudo shutdown -r now

Once it's back up and running open up a terminal and run.
pulseaudio --start

Then run bluetoothctl
Use "help" if you want more details about the available commands. The first time, you'll have to run the following:

power on
agent on
scan on
wait for the device to be discovered, note it's address (you can then use tab for auto-completion). For example, a set of ear buds I have show as Device 58:B3:BD:18:21:CE A90 Pro
pair 58:B3:BD:18:21:CE
trust 58:B3:BD:18:21:CE
connect 58:B3:BD:18:21:CE wait for the confirmation of connection and then type quit

Now we edit edit /etc/pulse/default.pa
sudo nano edit /etc/pulse/default.pa

Add this to the bottom of the file, then save and exit.

# automatically switch to newly-connected devices
load-module module-switch-on-connect

Then edit edit /etc/bluetooth/main.conf
sudo nano /etc/bluetooth/main.conf

Make sure this is showing at the end.

[Policy]
AutoEnable=true

Edit the bluetooth service with
sudo nano /lib/systemd/system/bluetooth.service

Look for this line:
ExecStart=/usr/lib/bluetooth/bluetoothd
and add --plugin=a2dp to the end so it looks like:
ExecStart=/usr/lib/bluetooth/bluetoothd --plugin=a2dp

Restart the service with:
systemctl daemon-reload
systemctl restart bluetooth

I wanted to be able to switch tracks and control the volume from four keys, switching the tracks was easy and just needed this adding into the /boot/config.txt file.

sudo nano /boot/config.txt

Add this to the end.

dtoverlay=gpio-key,gpio=16,keycode=33,label="Next"
dtoverlay=gpio-key,gpio=19,keycode=32,label="Previous"
dtoverlay=gpio-shutdown

I used similar options for the volume but nothing happened, so a bit of python controls this.

nano mixer.py

Paste this lot in

#!/bin/python
from gpiozero import Button
from signal import pause
from subprocess import Popen

def increase_volume():
global is_muted
if is_muted:
toggle_volume()
Popen(['amixer', 'sset', 'Master', '2%+'])

def decrease_volume():
global is_muted
if is_muted:
toggle_volume()
Popen(['amixer', 'sset', 'Master', '2%-'])

def toggle_volume():
global is_muted
Popen(['amixer', 'sset', 'Master', 'toggle'])
is_muted = not is_muted

def mute_volume():
global is_muted
if not is_muted:
toggle_volume()

is_muted = False #set it off to begin with

button_up = Button(20)
button_up.when_pressed = increase_volume
button_down = Button(21)
button_down.when_pressed = decrease_volume
button_down.when_held = mute_volume
pause()

I've created the music folder with:
sudo mkdir /mnt/Music
sudo chmod 0777 /mnt/Music

Then created a link to the user folder with
cd ~/
ln -s /mnt/Music

Amend the smb.conf file with
sudo nano /etc/samba/smb.conf

Add this to the bottom, then save and exit.

[Music]
comment = MP3 Files
path = /mnt/Music
guest ok = yes
browseable = yes
create mask = 0777
directory mask = 0777
read only = no

Last thing is to get it all playing on startup.

I made a file to run at startup with:

sudo nano /usr/local/bin/runmusic

This is the contents of the file:

#!/bin/bash
cd /home/username/Music
pulseaudio --start
amixer sset Master 40%,40% on
python /home/username/mixer.py &
mpg123 -CvZ --stereo --gapless *.mp3

Save that and then run:
sudo chmod +x /usr/local/bin/runmusic

Next up is:
sudo nano ~/.bashrc

Add this to the end:
/usr/local/bin/runmusic

And finally, make a file called winstall.sh or something, it really isn't important.

nano winstall.sh

Copy this lot into it

mkdir ~/temp
cd ~/temp

echo "Installing Window Networking Service"
wget https://github.com/christgau/wsdd/archive/master.zip
unzip master.zip
sudo mv wsdd-master/src/wsdd.py wsdd-master/src/wsdd
sudo cp wsdd-master/src/wsdd /usr/bin

echo "[Unit]">wsdd.service
echo "Description=Web Services Dynamic Discovery host daemon">>wsdd.service
echo "; Start after the network has been configured">>wsdd.service
echo "After=network-online.target">>wsdd.service
echo "Wants=network-online.target">>wsdd.service
echo "; It makes sense to have Samba running when wsdd starts, but is not required">>wsdd.service
echo "Wants=smb.service">>wsdd.service
echo "[Service]">>wsdd.service
echo "Type=simple">>wsdd.service
echo "ExecStart=/usr/bin/wsdd --shortlog">>wsdd.service
echo "; The following lines can be used for a chroot execution of wsdd.">>wsdd.service
echo "; Also append '--chroot /run/wsdd' to ExecStart to enable chrooting">>wsdd.service
echo "; AmbientCapabilities=CAP_SYS_CHROOT">>wsdd.service
echo "ExecStartPre=/bin/mkdir -p /run/wsdd">>wsdd.service
echo "ExecStartPre=/usr/bin/install -d -o nobody -g nogroup -m 0700 /run/wsdd">>wsdd.service
echo "ExecStopPost=rmdir /run/wsdd">>wsdd.service
echo "[Install]">>wsdd.service
echo "WantedBy=multi-user.target">>wsdd.service

sudo mv wsdd.service /etc/systemd/system/wsdd.service
sudo systemctl daemon-reload
sudo systemctl start wsdd.service
sudo systemctl enable wsdd

sudo systemctl daemon-reload
sudo service smbd restart

cd ~/
rm -rf temp

run it with sh winstall.sh

Once completed you should find the Raspberry Pi visible in the Windows Network

Save and then reboot.

To get my headphones to connect I have to put them back in the case and take them out once the Pi has started up. You could use the audio out on a Pi 3 or Pi4 or add a USB sound card to your Pi Zero. I don't really want any more wires.

Last thing I'll be doing is adding a charge socket to the bottom and power off button to shut it down cleanly.

I'm not clever enough to think this lot up by myself so thanks to Actuino at https://gist.github.com/actuino/9548329d1bba6663a63886067af5e4cb for the initial guidance and someone else for the python mixer script.

Tuesday, 1 August 2023

Raspberry Pi Access Point

So you go on holiday and you take your tablets, laptop, phones and other stuff that connects to wifi. You then have to go and enter the new network details into each device to the new network and you put the details away and then find there's something else you haven't connected.

Wouldn't it be nice to take your own wifi connection with you.

So, I had a spare Raspberry Pi zero W version 2, broken camera port, a nice little case, a micro USB to large USB adaptor and some hot glue. All I needed was a second wifi adaptor.

I got this one from our friends at Amazon.

You don't have to get this one, I bought it and it works but feel free to try out any other ones.

First thing of course is to install Raspbian onto the Pi. I've gone for the lite 32 bit version. No desktop but it really isn't a problem. I'm not going through the setup process as if you can't do that you shouldn't do this. And all the config is done through ssh to the onboard wifi. Anything below that's in bold and italics is ok to copy and paste.

Once you have finished setting it up, plug the adaptor in and you'll find like I did that although it's detected it doesn't work, yet.

The documentation with the adaptor gives you a link to the manufacturers website.

On the webpage it tells you to run the following.

sh -c 'wget linux.brostrend.com/install -O /tmp/install && sh /tmp/install'

It takes a while and then it just works, you'll have the onboard adaptor of wlan0 and this one wlan2.

Now we start doing other things and getting some software installed.

sudo apt install hostapd dnsmasq mc

I like mc, it's like Xtree Gold from the old dos days and is a great way to navigate the file system.

Now we run this.

sudo DEBIAN_FRONTEND=noninteractive apt install -y netfilter-persistent iptables-persistent

After that reboot with sudo reboot.

Once it's restarted more configuring files to get it all working.

sudo nano /etc/dhcpcd.conf

Paste all this in at the end.

interface wlan1

static ip_address=192.168.4.1/24

nohook wpa_supplicant

Save the files each time you finish, then onto.

sudo nano /etc/sysctl.d/routed-ap.conf

Paste this in and then save.

# Enable IPv4 routing

net.ipv4.ip_forward=1

Add a firewall rule with

sudo iptables -t nat -A POSTROUTING -o wlan0 -j MASQUERADE

Save the firewall rules with:

sudo netfilter-persistent save

And now setup DHCP and DNS stuff

sudo mv /etc/dnsmasq.conf /etc/dnsmasq.conf.orig

sudo nano /etc/dnsmasq.conf

Add the following to the file and save it.

interface=wlan1

dhcp-range=192.168.4.2,192.168.4.20,255.255.255.0,24h

domain=wlan

address=/gw.wlan/192.168.4.1

Now we setup the access point software.

sudo nano /etc/hostapd/hostapd.conf

Paste this in, changing the country code to where you live, the ssid to the same as your home one if you want and the passphrase needs to be changed too.

country_code=UK

interface=wlan1

ssid=SSID

hw_mode=g

channel=7

macaddr_acl=0

auth_algs=1

ignore_broadcast_ssid=0

wpa=2

wpa_passphrase=PWD

wpa_key_mgmt=WPA-PSK

wpa_pairwise=TKIP

rsn_pairwise=CCMP

Now we run this to get it starting up when the pi boots.

sudo systemctl unmask hostapd

sudo systemctl enable hostapd

sudo systemctl start hostapd

Then give it one final reboot and you should see a new wifi connection pop up.

That's about it really.

Thanks to hackster.io for the initial guidance and Github for a little help in making it work.

You can use just about any Pi for this, seems to work quite well and I may even add a connection to my vpn from it.

If you want to connect the Pi to a different wifi connection when you're away and travelling, boot it up, ssh into it and run

sudo raspi-config

Select option 1

Then select S1 and enter the wifi connection details there. There may be a more elegant way like setting up a graphical desktop but this is nice and minimal and it works.

Here's some pictures of the complete thing with a few magnets attached to the back to make it easy to stick to things. And yes, I went overboard with the hot glue gun as I was going to make something that was waterproof first.

Hope this all makes sense to you and have fun.

Saturday, 1 January 2022

Raspberry Pi Music Streaming

I want to be able to play music from my PC, phone tablet to my hifi system which is on the other side of the room. Bluetooth seems to drop out and I mostly use Spotify or Itunes as a music player.

I thought I'd have a look at what could be done with a Raspberry Pi and an external sound card to improve the standard sound quality. In the end I tested this out with a Raspberry Pi zero W which worked quite well and ended up running it on a Raspberry Pi Zero 2.

For Spotify to work you do need Spotify premium but iTunes will work quite happily with local files.

I'm not going through with how to install Raspbian onto an SD card and configure the wifi settings here.

Here's the sound card I got hold of from Amazon. £6.99 and it seems to work quite well. You'll also need an adaptor to connect this to the micro USB socket if you're using a Pi Zero.

Once that's all connected it together and you have Raspbian Lite installed on an SD card it's time to get it up and running

As always let's update the os first.

sudo apt-get update

sudo apt-get upgrade

Then we use the following line to install raspotify

curl -sL https://dtcooper.github.io/raspotify/install.sh | sh

Once it's completed we can edit some settings with:

sudo nano /etc/raspotify/conf

Look for the following line.

# Device name.

# Raspotify defaults to "raspotify (*hostname)".

# Librespot defaults to "Librespot".

# LIBRESPOT_NAME="Music1"

Uncomment the last line and change the Music1 to whatever you want to call it.

Now we activate the USB sound card

sudo nano /usr/share/alsa/alsa.conf

defaults.ctl.card 0

defaults.pcm.card 0

Change the above to the settings shown below

defaults.ctl.card 1

defaults.pcm.card 1

Save the file and then run sudo alsamixer

This should show the display below, just turn the sound all the way up.

If you now run sudo service raspotify restart you should see the device name showing up in your Spotify client, if you connect the audio output to your hifi you can play music from your devices to it.

Now we're going to add Airplay support for Itunes.

sudo apt-get install autoconf automake avahi-daemon build-essential git libasound2-dev libavahi-client-dev libconfig-dev libdaemon-dev libpopt-dev libssl-dev libtool xmltoman

git clone https://github.com/mikebrady/shairport-sync.git

cd shairport-sync

autoreconf -i -f

./configure --with-alsa --with-avahi --with-ssl=openssl --with-systemd --with-metadata

make

sudo make install

This may take some time.

Once it's completed we just need to make sure the service runs on restart.

sudo systemctl enable shairport-sync

Give it a reboot and it should all be running nice and happy.

You should be able to see the device in Spotify and Itunes as shown below.

Thanks to the Raspotify people and Jeff Thompson for my inspiration

Saturday, 17 April 2021

PiCorder (The Next Generation)

The original PiCorder worked, took ages to start recording and I couldn't hear what I was recording as it was being recorded, it was time for a rethink.

I decided to throw away the original idea and add a small USB sound card, this is what I got in all for it, apart from the Raspberry Pi Zero W of course.

These are fantastic, reversible USB micro leads, not USB C, USB micro, they can go in either way around.

I got them from Amazon, £7.99 for 2, there are probably other places so please shop around/

This is the mic I got, again from Amazon, £7.59, you can probably use any mic with a 3.5mm jack, I didn't have one so this did the job.

Nice little case for it all to go in, as it's transparent you can use the onboard LED as a sort of status thingy, Amazon again and £8.99

Then there's the sound card, there's quite a few of these about, I got two and they seem to work quite well to be fair. Again from Amazon at a cost of £7.59.

You don't have to get one of these but in my mind it makes the sound card fit better with the case. Cost for the two is £5.10 from Amazon.

Power was the next thing on my shopping list, I got one of these, mainly because I liked the look of it and if you press the test button on it then it turns the power back on, more on that later. I managed to get one from Morrisons at £9.99.

And last but not least apart from the Raspberry Pi itself was something to give me a bit of directionality without being too big and intrusive and was light. I looked at bullet mics and parabolic dishes and although the dish itself probably gives the best results I fell back on the idea of the really old hearing aids, basically a funnel. I found these in Poundland and managed to get some grey ones.

You need a micro SD card too of course, I got a 32GB one, I would suggest getting a decent make, I got some cheap ones and they gave up after about a week.

Put together will all the magic stuff from a glue gun and the old favourite Blu Tack and it looks like this, the special effect guys from Blakes 7 couldn't have done better. You have a headphone socket so that you can hear what you're recording and you can collapse the funnel back to make it less obtrusive. It's not brilliant but it works, the funnel does get rid of some outside noise and I'll include some sound samples later on.

I also added some small push buttons, top one is connected to GPIO 3 and ground, the bottom to GPIO 13 and ground. I soldered these directly to the board but you can break it and the warranty is void of course.

Time to put it all together now, I'm not going through how to install the OS onto the SD card, I used Raspbian Lite for it, don't really need a desktop environment and it's all set up by SSH so make sure that's enabled.

We're going to have to get the sound card working first and change the playback and sound levels, run the following:

sudo nano /usr/share/alsa/alsa.conf

defaults.ctl.card 0

defaults.pcm.card 0

Change these to a 1 as shown below.

defaults.ctl.card 1

defaults.pcm.card 1

Run sudo alsamixer and you should see this, select the Speaker and Mic and up the levels and we are now ready to get on with the rest.

We're going to turn off bluetooth as this seemed to be the cause of some electrical noise.

Open up the /boot/config.txt file with:

sudo nano /boot/config.txt

Add the following to the bottom of the file

# Disable bluetooth

dtoverlay=disable-bt

# Allows power off and on

dtoverlay=gpio-shutdown

Now we remove the bluetooth software

sudo systemctl disable hciuart.service

sudo systemctl disable bluealsa.service

sudo systemctl disable bluetooth.service

sudo apt-get purge bluez -y

sudo apt-get autoremove -y

Now reboot to continue, once it's back up you should find a press of the top button will shut the Pi down and once it's closed down completely the status lights on the charger will go off. Press the test button on the charger and the Pi will come back on.

I've made a small script called mtbootme which is in the bin folder, makes it easier to add things when it boots up, just run sudo nano /bin/mtbootme and add the following lines

# Turns the light off

echo 0 >/sys/class/leds/led0/brightness

# Makes the light flash

echo heartbeat >/sys/class/leds/led0/trigger

Save it and make it executable with sudo chmod +x /bin/mtbootme

Now we need a way of recording the sound and also of being able to monitor it while it's recording. There's probably a better way of doing it but I came up with this, there's about a second delay.

The bit of shell script I use checks for a file number, if it's not there it starts at 1, if it is there it adds a 1 to it.

sudo nano /bin/mtcapture

Paste this lot in

#!/bin/bash

# shuts down the wifi

ifconfig wlan0 down

# Turns the LED on fully

echo 0 >/sys/class/leds/led0/brightness

echo 1 >/sys/class/leds/led0/brightness

# sorts the file number

FILE=/share/filenum

if [ -f "$FILE" ]; then

echo "$FILE exists."

else

echo "$FILE does not exist."

echo "0"> /share/filenum

read newfile < /share/filenum

echo $newfile

newfile=$((newfile+1))

echo $newfile > /share/filenum

# Records the noises

arecord -f cd - | tee /share/AudioTux1-$newfile.wav | aplay - &

echo $newfile

# updates the file number

echo $newfile > /share/filenum

Make it executable with sudo chmod +x /bin/mtcapture

That's how we start it recording, don't run this just yet as it will turn the wifi off and you'll lose your connection or rem out the wifi line while testing.

Now we do the stop recording file

sudo nano /bin/mtstop

#!/bin/bash

# Kill all recording services

pkill mtcapture

pkill arecord

pkill aplay

# Starts up the wifi

ifconfig wlan0 up

# Flashes the green light so we know recording has stopped

echo 0 >/sys/class/leds/led0/brightness

echo heartbeat >/sys/class/leds/led0/trigger

Save it and make it executable again with sudo chmod +x /bin/mtstop

A bit of python now to monitor the stop start button.

sudo nano record.py

This lot goes in here.

# !/bin/python

import RPi.GPIO as GPIO

import time

from subprocess import call

import os

GPIO.setmode(GPIO.BCM)

GPIO.setup(13,GPIO.IN,pull_up_down=GPIO.PUD_UP)

flag = False

while True:

input = GPIO.input(13)

if(input == False):

if(flag == False):

os.system("/bin/mtcapture")

flag = True

time.sleep(0.4)

else:

os.system("/bin/mtstop")

flag = False

We don't need to make this executable to run it.

Finally we edit the rc.local file to get things working on startup

sudo nano /etc/rc.local

Add these two lines just before the exit 0 at the bottom

python2 /root/record.py &

/bin/mtbootme &

Save it and reboot and you're ready to go, one last thing I've done is to install samba so I can pull the files off it. All the recordings are saved in the directory /share.

Install Samba and MC, it's one of the first things I install as it makes navigating the structure and editing really easy.

sudo apt install samba mc

Once done edit the samba config file

sudo nano /etc/samba/smb.conf

Add this to the bottom[Shares]

path = /share

public = yes

browseable = yes

writeable = yes

delete readonly = yes

force create mode = 777

force directory mode = 777

writeable = yes

directory mode = 777

create mode = 777

Save it and restart samba with sudo service smbd restart

And you are now ready to go, once you've powered it up the green status LED should be flashing, plus some headphones into the socket and press the lower button and it should start recording, you'll hear a delayed sound in the headphones, press it again and it will stop.

It's not supposed to be a professional bit of equipment, it's small, it's light and it sort of works and more than anything it's a bit of fun and it will get you more involved with nature.

Advantages of the funnel at the end are that it's completely collapsible, you can put it in a pocket and fold it over as shown below and it still works. Disadvantages are that you look like a mad professor when you're out and about with it.

And finally some sample sounds, there's a bit of noise in the background which is from a nearby industrial unit,

Sunday, 28 March 2021

PiCorder

I enjoy getting out and about when I can, nature reserves are a great place to go and I've thought a while about recording birdsong and other noises such as rivers and so on. I could use a phone but where's the fun in that and then once you get the phone out there's the distractions of social media. It's nice to leave those things behind.

I decided to knock up a sound recorder using a Raspberry Pi Zero W, it's never going to be brilliant, there's no display or controls on it so the sound is a fixed level but it had to be tried.

I got hold of one of these from Amazon, no drivers needed, just plug it in and it will work is what was said everywhere. Not quite really but in the end it wasn't too hard to get sorted.

I followed all the initial instructions and nothing happened, just an error so more searching on the Google thing found me this.

sudo nano /usr/share/alsa/alsa.conf

defaults.ctl.card 0

defaults.pcm.card 0

Change these to a 1 as shown below.

defaults.ctl.card 1

defaults.pcm.card 1

Save the file and it, sort of. Loads of noise on the recordings and suggestions of adding capacitors across the USB ports to dampen it down seemed drastic. Not a lot seemed to work, looked like it was going to be a complete failure.

So I had a poo and it came to me, first thing was get the recording level
up, I'm running everything here as root, there's nothing on here that is precious.

Run alsamixer and you should see this:

Press F4 to select the capture device and using the arrow keys increase the gain to the top as shown below.

Press escape to leave it.

As mentioned before, I was getting loads of noise when I tried this earlier, I decided to hard wire power and a record button onto the Pi, this meant soldering the power wires to the board on pins 2 and 6, you can see the complete list of pins here.

And the stop start button soldered to pins 36 and 34 (GPIO 16 and Ground) Don't blame me if you break your Pi while doing this.

I got hold of one of these so I could connect the mic into the Pi, no cables needed, again from them Amazon people.

Then I decided that as I wanted to keep power usage down I would disable the bluetooth connection and remove the bluetooth software.

Open the config.txt file with

sudo nano /boot/config.txt and then add this to the bottom of the file:

# Disable Bluetooth

dtoverlay=disable-bt

Save and close it then run the following to remove all the bluetooth stuff.

sudo systemctl disable hciuart.service

sudo systemctl disable bluealsa.service

sudo systemctl disable bluetooth.service

sudo apt-get purge bluez -y

sudo apt-get autoremove -y

I rebooted and carried out a test recording and there was no electrical noise apart from the odd regular buzz, I disabled the wifi and retested and this time no noise at all.

It was now time to stick it in a box and make it work.

I needed a way of getting the files off afterwards, easiest option was install samba with

apt install samba

Create a directory with

mkdir /share

Open the samba config with

nano /etc/samba/smb.conf

Add the following at the bottom

[Sounds]

path = /share

public = yes

writeable = yes

browseable = yes

Restart Samba with service smbd restart

I decided to create a sound recording service with:

nano /etc/systemd/system/soundrec.service

[Unit]

Description=Sound Recording

[Service]

ExecStart=/bin/mtcapture

WorkingDirectory=/share

StandardOutput=inherit

StandardError=inherit

Restart=always

User=root

[Install]

WantedBy=multi-user.target

I'm not enabling the service to auto start

Create some files in the bin folder:

nano /bin/mtstart

#!/bin/bash

# shuts down the wifi

ifconfig wlan0 down

service soundrec start

# sleep 1

echo 0 >/sys/class/leds/led0/brightness

# Makes the green LED flash so we know it's recording

echo heartbeat >/sys/class/leds/led0/trigger

nano /bin/mtstop

#!/bin/bash

service soundrec stop

# Starts up the wifi

ifconfig wlan0 up

# sleep 1

echo 0 >/sys/class/leds/led0/brightness

sleep 3

# Leaves the green LED on so we know it's finished

echo 1 >/sys/class/leds/led0/brightness

nano /bin/mtcapture

#!/bin/bash

for (( ; ; ))

FILE=/share/filenum

if [ -f "$FILE" ]; then

echo "$FILE exists."

else

echo "$FILE does not exist."

echo "0"> /share/filenum

read newfile < /share/filenum

echo $newfile

newfile=$((newfile+1))

echo $newfile > /share/filenum

arecord -f cd /share/AudioTux1-$newfile.wav

done

This increments the file number each time it's run so we can have as many files as we want until we run out of space.

You need to make all these executable with chmod +x filename

Then a little bit of python to get it working

nano record.py

# !/bin/python

import RPi.GPIO as GPIO

import time

from subprocess import call

import os

GPIO.setmode(GPIO.BCM)

GPIO.setup(16,GPIO.IN,pull_up_down=GPIO.PUD_UP)

flag = False

while True:

input = GPIO.input(16)

if(input == False):

if(flag == False):

print "Start"

os.system("/bin/mtstart")

flag = True

time.sleep(0.4)

else:

print "Stop"

os.system("/bin/mtstop")

flag = False

time.sleep(0.4)

Open up the rc.local file with

nano /etc/rc.local

And add the following just before the exit 0 at the bottom

python2 /root/record.py &

Then restart it, once it's up and running, pressing the button connected to the GPIO pins should start it recording. A second press will stop if, while it's recording the wifi will be disabled. If you want you can add a second button connected to pins 5 and 6 (GPIO 3 and Ground), add the following to the bottom of the /boot/config.txt file.

dtoverlay=gpio-shutdown

Reboot and on press on the button will shut the pi down, a second press will restart it.

Here's the finished item, it's not overly pretty as I got the wrong case but it works, the USB mic at the top can be unplugged and put on an extension cable and possibly fitted into a parabolic dish, but that's for another time.

It does work, seems to take ages to start recording as the service has to start and once started it then takes ages to stop the service.

It needed a rethink and so was born "PiCorder, the Next Generation"

Instructions are here.

Some more Pi

Been a while since I've done anything on here, let's face it 2020 was a washout and the first bit of 2021 has gone that way too. It does mean that things at home have come higher up the list of things to do and one of those things was to add a camera to a Raspberry Pi, point it at the sky and take pictures. The main idea was to get some shots of the stars moving but the clouds looked interesting too.

The first attempt was a quick lash up stuck in a plastic bag to give it some water proofing and put on the floor in the garden out of site of the street light at the back. This was a Raspberry Pi 2 and the version 1 camera which can go down to about a 6 second exposure, nothing lower than that so the stars didn't really stand out that well and there is a lot light pollution too.

Here's my first test, not great but it seems to show a bit of promise if we can get a clear night and even more so if we could try somewhere with a darker sky.

The other plan or project was a camera at the from of the house which apart from doing some timelapse would also take a picture every day at dawn, noon and sunset for a year from the 21st of March. For no other reason than it can be done. The noon bit was fairly straight forward, the sunrise and sunset were going to be harder. Until I came across something called "Heliocron". You can use this app to run a task at various times of the day and it calculates sunrise and sunset for you. Many thanks to the author for this.

Let's get started with my SkyCam as I call it, to run properly the Raspberry Pi needs a connection to a network so it can get the correct time. I have a plan B for a travel version but I'll come back to that.

I'm going to build this with a Raspberry Pi 3, a version 2 camera which gives 8Mp and shutter speeds down to 10 seconds. I need a waterproof case so I can stick it outside and a power and ethernet lead out of it. There will be some code which I've borrowed and modified from various searches, I can't remember where I got them but if it's yours then it's much appreciated.

This may not be the best way of doing it but it seems to work.

The finished article looks like this, I've managed to find an old Tripod bush so I can mount it outside and adjust the position.

Using the above mentioned Heliocron, it changes the exposure settings as it gets darker and lighter to keep some detail. I'm not clever enough to get it to take a measurement and do it automatically.

The script that will be taking the pictures is called:

mtshutter

There's going to be a couple of versions of it called mtday, mtdusk, mtearly and mtnight.

I stick the mt in front as it makes them easier to find.

I'm storing them in the /bin folder, I can't see any reason as to why not but if I'm wrong I'm sure somebody will tell me.

They all look fairly similar except for the picture taking settings, starting with mtshutter:

The pictures once taken are stored on a small file server mounted at /mnt/webcam in their own folder called skycam1, there may be another one in the future. You can of course change the location to wherever you want.

#!/bin/bash