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by BBUK
Fri Jul 06, 2018 2:21 pm
Forum: Advanced users
Topic: performance - using p3b+ as wlan router
Replies: 10
Views: 668

Re: performance - using p3b+ as wlan router

This may sound a little strange given the comments above but I had a similar problem. I found it was caused by the DHCP server on the Pi attempting to give IP addresses over all interfaces rather than just wlan0. Try configuring whichever DCHP server you are using to only apply IP addresses over wla...
by BBUK
Fri May 04, 2018 8:55 am
Forum: Advanced users
Topic: Script for changing raspberry pi hostname during boot sequence
Replies: 4
Views: 305

Re: Script for changing raspberry pi hostname during boot sequence

The only time I have have seen this error is by pasting text into a SSH terminal window from Windows notepad. It was caused by DOS-style line endings. Try converting the line endings to Unix style. Loads of ways of doing this (dos2unix for example). This perl one-liner also works: perl -pi -e 's/\r\...
by BBUK
Thu May 03, 2018 1:26 pm
Forum: Advanced users
Topic: Calling C from Python
Replies: 1
Views: 225

Re: Calling C from Python

Hi Rob.

Although it was a bit of a faff at first, I found building C extensions to be the best route. The two references I used most were:

https://docs.python.org/2/extending/extending.html (there is a similar page for Python3)

http://dfm.io/posts/python-c-extensions/

Have fun

BBUK
by BBUK
Wed Mar 28, 2018 4:28 pm
Forum: C/C++
Topic: mpu6050 with kalman filter
Replies: 6
Views: 2174

Re: mpu6050 with kalman filter

Just a little follow up to anyone that is trying to click the link I posted above - it won't work and the solution has developed. The released version of the code combines the data from two MPU6050s and pushes that to an extended Kalman filter. The main part of the code is now in the "grabber.c" fil...
by BBUK
Fri Mar 23, 2018 4:53 pm
Forum: Automation, sensing and robotics
Topic: A Tower Bell "pullometer"
Replies: 0
Views: 155

A Tower Bell "pullometer"

Hi all. A write-up of my latest Pi project which is a device to aid those learning (and those teaching others to learn) the art of tower bell ringing. It requires a lot of practice to do well. It is true that, fundamentally, you are just pulling on a rope (called a sally in the parlance) but you hav...
by BBUK
Wed Feb 28, 2018 4:53 pm
Forum: Advanced users
Topic: Bluetooth RFCOMM Server not working when using SystemD
Replies: 2
Views: 261

Re: Bluetooth RFCOMM Server not working when using SystemD

I see that the daemon uses stdout. I am not sure where that will end up when executed via systemd and your daemon could well be hanging at any stdout writes. Have you tried the daemon code in a form that does not use stdout (no daemon would normally be attached to a terminal)? As a quick and dirty t...
by BBUK
Wed Feb 07, 2018 2:16 pm
Forum: C/C++
Topic: mpu6050 with kalman filter
Replies: 6
Views: 2174

Re: mpu6050 with kalman filter

Have a look at this file in one of my repos https://github.com/BBUK/Bell-Boy/blob/master/bb_dcmimu/bb_dcmimu.c . Specifically the calculate function. This implements an EKF from https://github.com/hhyyti/dcm-imu with what I found to be really stunning results for my use case. It is not for the MPU60...
by BBUK
Mon Aug 07, 2017 2:31 pm
Forum: Advanced users
Topic: Using an adxl345 accelerometer to detect vibrations within specific frequency range
Replies: 1
Views: 974

Re: Using an adxl345 accelerometer to detect vibrations within specific frequency range

Howdy. I have been messing around *a lot* with accelerometers recently but for a different application. The way I would tackle this is, in theory, straightforward - take samples from the ADXL345 applying a suitable low pass filter (it looks like the device can do this itself) then apply the samples ...
by BBUK
Tue Aug 01, 2017 3:47 pm
Forum: General discussion
Topic: My Raspberry Pi 3 Speed
Replies: 8
Views: 894

Re: My Raspberry Pi 3 Speed

The OP may well be connecting over wifi and wifi throughput increases significantly in the absence of noisy appliances like the "old vacuum" (or in my case the microwave oven). I bet that's what he is experiencing.

BBUK
by BBUK
Fri Jul 21, 2017 1:39 pm
Forum: General discussion
Topic: WANTED: Wifi testers!
Replies: 12
Views: 1400

Re: WANTED: Wifi testers!

Heater, I only had a quick scan myself but the TL;DR seems to be that some IP packets going through the brcmfmac driver have a priority setting. When that setting is at 0x10 or 0x08 some packets are silently lost, causing wifi issues. The PR (now merged with 4.12) forces the setting to 0x00. This is...
by BBUK
Fri Jul 21, 2017 1:15 pm
Forum: General discussion
Topic: WANTED: Wifi testers!
Replies: 12
Views: 1400

Re: WANTED: Wifi testers!

Happy to help.

Unless you have any objections, I'll test on 4.9 and the Zero W as that matches a particular use case that I am looking to use internal wifi for. I can apply the change directly to the 4.9 source (it's only one line!)

BBUK
by BBUK
Tue May 09, 2017 3:50 pm
Forum: Automation, sensing and robotics
Topic: Poor man's ADC
Replies: 4
Views: 867

Re: Poor man's ADC

Thanks Joan (and triphil). I suppose I cannot argue much against the ease of a solution that uses a cap and a resistor rather than two resistors but for monitoring battery voltage there is a problem with timing the charging of a cap in that we can't have the cap charging much above 3.3V to protect t...
by BBUK
Tue May 09, 2017 11:18 am
Forum: Automation, sensing and robotics
Topic: Poor man's ADC
Replies: 4
Views: 867

Poor man's ADC

Hi all. I have a RPi zero powered through a PP3 9v battery and a switcher to take the voltage down. I would like to monitor the remaining power of that battery by measuring its voltage. A quick and easy way to do this would be with a resistive divider connected directly to a GPIO pin. From what I ca...
by BBUK
Wed Feb 08, 2017 1:56 pm
Forum: General discussion
Topic: How to connect a SDR to a pi3 then wirelessly access it?
Replies: 6
Views: 1521

Re: How to connect a SDR to a pi3 then wirelessly access it?

I think Snapcast would be a good solution for this https://github.com/badaix/snapcast . As long as the output from the SDR software can be piped to a file then the Snapcast server can pick it up and send it over the network to a device that has a Snapcast client running on it (there is a client for ...
by BBUK
Tue Dec 13, 2016 11:31 am
Forum: Python
Topic: why does Pygame script wait for ESC key press on auto start
Replies: 3
Views: 967

Re: why does Pygame script wait for ESC key press on auto st

Hi windy54.

Your problem does not look exactly like one that I was experiencing but try my solution here: http://stackoverflow.com/questions/1703 ... it-display

Have fun

BBUK
by BBUK
Sun Oct 09, 2016 5:55 am
Forum: Graphics, sound and multimedia
Topic: Virtual Window with Parallax
Replies: 2
Views: 628

Re: Virtual Window with Parallax

I hadn't posted any code as I just have a slow updating proof of concept that will need a load of work. It was more of a generic, "Have fun with life" :lol:
by BBUK
Sat Oct 08, 2016 4:00 pm
Forum: Graphics, sound and multimedia
Topic: Virtual Window with Parallax
Replies: 2
Views: 628

Virtual Window with Parallax

Hi all. I have been playing around with something this afternoon. I had an idea to convert a TV to a virtual window using a Pi. The nice bit is that the display changes as the viewer moves his/her head to simulate what would happen in a real window (you can see more of the outside when you are close...
by BBUK
Thu Oct 06, 2016 7:19 am
Forum: Graphics, sound and multimedia
Topic: "Bakelite" Pi Music Player with Touch Screen
Replies: 2
Views: 1478

"Bakelite" Pi Music Player with Touch Screen

Hi all. A write up of another Pi project I have completed. See video https://www.youtube.com/watch?v=O1h3-DS6LK8 . What you see was originally a Bush DAC10 radio. It was nearly working when I bought it and would have been a pretty easy fix to get it fully functional so I felt quite a lot of guilt in...
by BBUK
Fri Sep 09, 2016 1:58 pm
Forum: Wanted
Topic: Paintball - fake briefcase bomb
Replies: 5
Views: 2322

Re: Paintball - fake briefcase bomb

Hmm again ... the inside of the case will then have to be treated as being exposed to a harsh environment (i.e. people with muddy fingers, pressing things hard and rapidly). You will also have to create somewhere safe and tamper proof for the more delicate elements like the controller, amplifier, ba...
by BBUK
Fri Sep 09, 2016 1:14 pm
Forum: Wanted
Topic: Paintball - fake briefcase bomb
Replies: 5
Views: 2322

Re: Paintball - fake briefcase bomb

Hmm, the internals may be safe but the LED display needs to be visible and keypad has to be accessible from the outside. These are the difficult bits - they can't be just stuck onto the outside and a hole drilled through the case for the wiring (or rather they can but the lifetime in the sort of env...
by BBUK
Fri Sep 09, 2016 12:21 pm
Forum: Wanted
Topic: Paintball - fake briefcase bomb
Replies: 5
Views: 2322

Re: Paintball - fake briefcase bomb

Looks interesting - the software side is trivial and the RasPi would be overkill for something like this (although a Pi Zero, even if overkill may well be the most cost-effective solution). The real issue is hardware. It will be no problem to source "a" keypad but there will be much more work to fin...
by BBUK
Mon Jun 13, 2016 10:24 am
Forum: Graphics, sound and multimedia
Topic: Looking for a 5"x2" display
Replies: 1
Views: 532

Re: Looking for a 5"x2" display

Howdy. I had a similar issue - for me the project is retrofitting a LCD display into a bakelite radio. After a lot of searching on Alibaba, I found a supplier of bar-type LCDs and this is one supplied by them which is pretty close to the size you want (there are others that they sell too). https://c...
by BBUK
Wed Jun 08, 2016 8:41 am
Forum: General discussion
Topic: miniDLNA on Jessie
Replies: 4
Views: 1469

Re: miniDLNA on Jessie

You could insert a delay in the minidlna systemd unit file as tpylkko suggests but the solution I adopted in a similar scenario was to mount the USB drive via systemd see (for example) https://oguya.ch/posts/2015-09-01-systemd-mount-partition/ . The minidlna systemd unit file will then need to have ...
by BBUK
Tue May 31, 2016 10:15 am
Forum: Graphics, sound and multimedia
Topic: Audioplayer for touchscreen?
Replies: 3
Views: 1014

Re: Audioplayer for touchscreen?

Hi frau_mahlzahn I made this some time ago https://www.raspberrypi.org/forums/viewtopic.php?f=38&t=64478 . It's a bit out of date now (and does not use bluetooth) BUT the main python script uses a small touchscreen display as a frontend to MPD (see the youtube link) . MPD can be configured to pass i...
by BBUK
Tue May 31, 2016 9:59 am
Forum: Graphics, sound and multimedia
Topic: Actively biamped wifi speaker with UPS shutdown
Replies: 3
Views: 1773

Re: Actively biamped wifi speaker with UPS shutdown

Hi charlielaub Thanks for your comment! The only reason I went to town on the power/shutdown thing (and I really did!) was that I wanted to avoid SD card corruption if the Pi was not halted properly when power was removed. I personally have never suffered from this but seeing the Pi was in a sealed ...

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