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by MarkDH102
Thu May 09, 2019 6:31 am
Forum: Beginners
Topic: Sending e-mail notifications when temperature is over 8°C
Replies: 1
Views: 65

Re: Sending e-mail notifications when temperature is over 8°C

This is what I use to email temperature alarms from my sensor. import smtplib from email.mime.text import MIMEText from email.mime.multipart import MIMEMultipart from email.mime.image import MIMEImage import signal class TimeoutException(Exception) : pass def _timeout(signum, frame) : raise TimeoutE...
by MarkDH102
Tue Apr 30, 2019 6:13 am
Forum: General discussion
Topic: Problem with range of 433 Mhz receiver
Replies: 8
Views: 307

Re: Problem with range of 433 Mhz receiver

Signal levels are so weak, and the "modulation method" so simple, that even if 0.001% of a PI generated signal will overwhelm the receiver if its too close. It will simply "see" the 433MHz signal all the time. A "better receiver", (meaning more sensitive) will therefore not help. That's very intere...
by MarkDH102
Mon Apr 29, 2019 6:20 am
Forum: Beginners
Topic: raspberry pi as a server watchdog
Replies: 7
Views: 234

Re: raspberry pi as a server watchdog

The Raspberry Pi is just as likely to go down as your server in my opinion. Too much underlying code. I would look at using an ESP8266 or a similar Arduino solution. I have ESP8266 and Arduino code that has been running for a couple of years with no intervention ( and the internal watchdog has never...
by MarkDH102
Sat Apr 27, 2019 6:15 am
Forum: Troubleshooting
Topic: DHT22 Accuraty.
Replies: 2
Views: 101

Re: DHT22 Accuraty.

I too use the BME280.
I used to use the DHT22 but running the 2 in parallel showed the BME280 seemed to be more accurate.
My DHT22 were always reading about 20% over the correct level - but were consistent...
by MarkDH102
Sat Apr 27, 2019 6:07 am
Forum: General discussion
Topic: weight scales: Do-able with Raspberry?
Replies: 5
Views: 319

Re: weight scales: Do-able with Raspberry?

I have successfully used a Wii Fit board (Bluetooth to the Pi). I control power to the Wii Fit via a relay (which required dismantling the Wii Fit (very easy) ). I use it as a personal weigher. The other thing I had to do was attach a 1000uF capacitor across the 5V rail of my Pi zero W as when the W...
by MarkDH102
Tue Apr 09, 2019 6:25 am
Forum: General discussion
Topic: GIVE YOUR RASPBERRY PI SD CARD A BREAK: LOG TO RAM
Replies: 19
Views: 1897

Re: GIVE YOUR RASPBERRY PI SD CARD A BREAK: LOG TO RAM

In all of my data logging pi's, I log the data to RAM for 24 hours and then commit it to SD card (and email a copy) at midnight. Other than that my applications do not write to the SD card. These Pi's are also UPS protected... But I have had a couple of SD cards go write only on me (and only after a...
by MarkDH102
Fri Mar 29, 2019 8:07 am
Forum: Troubleshooting
Topic: VNC Interface won't stay enabled
Replies: 15
Views: 567

Re: VNC Interface won't stay enabled

No, I'm using the standard REALVNC. 3 * Pi0w are all exhibiting the same problem. All my pi's - Stretch - are updated once a month. I can't say when the problem started, as I had a power cut, all my pi's rebooted. Then found I couldn't connect. I only have a screen plugged into one of them and after...
by MarkDH102
Fri Mar 29, 2019 7:15 am
Forum: Python
Topic: RF Communication with Python (Send Only)
Replies: 11
Views: 2067

Re: RF Communication with Python (Send Only)

I actually use a homebrew ATMEGA328p internal Xtal, minimum components and a RFM12B module to do the sending/receiving and then connect it to my Pi0W via the serial port and 3v3 and drive all "send RF" comms that way.
by MarkDH102
Fri Mar 29, 2019 7:11 am
Forum: Troubleshooting
Topic: VNC Interface won't stay enabled
Replies: 15
Views: 567

Re: VNC Interface won't stay enabled

This really needs sorting or a sticky being put up somewhere. It seems to be catching a lot of people out.
Is it a bug in the kernel? Why after many years of VNC working fine has it suddenly started happening?
by MarkDH102
Tue Mar 19, 2019 4:34 pm
Forum: Troubleshooting
Topic: SOLUTION: VNC does not start on a headless Raspberry pi.
Replies: 7
Views: 1195

Re: SOLUTION: VNC does not start on a headless Raspberry pi.

Many thanks for this - I've just been redirected here from my own thread.
Works for me...
by MarkDH102
Tue Mar 19, 2019 4:33 pm
Forum: Troubleshooting
Topic: Why does my RealVNC start so late after boot up
Replies: 2
Views: 121

Re: Why does my RealVNC start so late after boot up

Many, many thanks for this pointer.
I now have a working system again.
I was beginning to tear my hair (what's left of it) out!
by MarkDH102
Tue Mar 19, 2019 7:29 am
Forum: Troubleshooting
Topic: Why does my RealVNC start so late after boot up
Replies: 2
Views: 121

Why does my RealVNC start so late after boot up

Here is my syslog from boot up to when RealVNC starts up. Obviously, I can't VNC in to my Pi until the service starts... To my untrained eye, I can't see anything untoward. Maybe the entries prior to reboot give a clue to somebody? Stretch - completely up to date, Pi0W. Mar 18 16:41:51 scraper vncse...
by MarkDH102
Wed Mar 13, 2019 3:43 pm
Forum: Troubleshooting
Topic: Pi0 W showing "no wireless interface" and won't connect via VNC
Replies: 2
Views: 117

Re: Pi0 W showing "no wireless interface" and won't connect via VNC

Ok, I am now beyond angry. I burned an old image from 3/3/18 to a backup card and it all worked. I then did an update & upgrade which took a looooooong time. It all still worked. I then did a dist-upgrade. Now, I can't get into VNC no matter what I do. It boots up, displays the desktop on my monitor...
by MarkDH102
Wed Mar 13, 2019 11:16 am
Forum: Troubleshooting
Topic: Pi0 W showing "no wireless interface" and won't connect via VNC
Replies: 2
Views: 117

Re: Pi0 W showing "no wireless interface" and won't connect via VNC

I've now put the SD card back in the original Pi0 W and lo and behold it is no longer seeing the WiFi in that one either.
What on earth could I have done wrong?
Incredibly frustrating - all resulting from an extremely brief power cut.
Thank goodness most of my stuff has been migrated to esp32's now...
by MarkDH102
Wed Mar 13, 2019 9:22 am
Forum: Troubleshooting
Topic: Pi0 W showing "no wireless interface" and won't connect via VNC
Replies: 2
Views: 117

Pi0 W showing "no wireless interface" and won't connect via VNC

My router lists the device. However, if I plug in a (non powered) 3 port USB hub with ethernet (not connected to anything), I am able to VNC in over the WiFi with no problems ??? It still says "no wireless interfaces" and only shows the ethernet connector icon in the menu bar. But it does show wirel...
by MarkDH102
Mon Mar 11, 2019 7:10 am
Forum: Python
Topic: Send hex commands via uart port
Replies: 4
Views: 274

Re: Send hex commands via uart port

The code looks fine to me. I use exactly the same type of thing to talk to a serial LCD. I guess you have the baud rate etc. correct for the camera. It strikes me that the 2 byte command you are sending is a bit "light". Are there no checksums involved or message terminating characters like carriage...
by MarkDH102
Wed Mar 06, 2019 5:32 pm
Forum: Troubleshooting
Topic: How to fix WiFi failure without rebooting
Replies: 2
Views: 93

Re: How to fix WiFi failure without rebooting

To turn off power saving mode with Edimax WiFi dongle, I do the following :

sudo nano /etc/modprobe.d/8192cu.conf

And add the 2 lines below then save.

# Disable Power Management
options 8192cu rtw_power_mgnt=0 rtw_enusbss=0

I too was plagued by the same problem, but not since doing this.
by MarkDH102
Wed Mar 06, 2019 5:25 pm
Forum: General discussion
Topic: Raspberry Pi3 connectivity from mobile
Replies: 4
Views: 150

Re: Raspberry Pi3 connectivity from mobile

You might wish to try weaved.com
I used it for something similar a while back.
I used it a while back. I have no idea if it still works the way Linux keeps changing the goalposts...
by MarkDH102
Sun Mar 03, 2019 7:17 am
Forum: Beginners
Topic: High CPU usage?
Replies: 7
Views: 317

Re: High CPU usage?

In Python : x = 0 while True : x = x + 1 Will use 100% CPU (on a Pi0) or 25% (on a 4 core Pi model). import time x = 0 while True : x = x + 1 time.sleep(1) # 1 second Will use next to no processing power. However while the sleep is active, your code is not running. Even using (0.01) (10mS) in the sl...
by MarkDH102
Sun Mar 03, 2019 6:59 am
Forum: AIY Projects
Topic: Does Google AIY still work on the Raspberry Pi?
Replies: 7
Views: 739

Re: Does Google AIY still work on the Raspberry Pi?

Also, Dougie, I assume you did not use Google's image file, but instead worked through their HACKING (https://github.com/google/aiyprojects-r ... HACKING.md) instructions? I used the hacking method and had no issues getting it to work with my own microphone (a USB one from a Nintendo Wii game!) and...
by MarkDH102
Fri Mar 01, 2019 7:10 am
Forum: AIY Projects
Topic: Does Google AIY still work on the Raspberry Pi?
Replies: 7
Views: 739

Re: Does Google AIY still work on the Raspberry Pi?

Yes, I found that link yesterday morning and went from scratch. Another complication was that my authorisation key had expired (they do after 6 months of activity apparently). But yesterday morning, I did finally get it all back up and running. Of course, my original code needed some modification th...
by MarkDH102
Thu Feb 28, 2019 12:20 pm
Forum: AIY Projects
Topic: Does Google AIY still work on the Raspberry Pi?
Replies: 7
Views: 739

Re: Google AIY - I've fallen down the LINUX rabbit hole...

Ok, with the original Stretch image from early 2018 that used to work, having been prompted by errors reported by my Python3 app I have installed - one at a time - each one inducing a new error : pip3 install google-auth pip3 install grpcio pip3 install google-cloud-storage pip3 install grpc However...
by MarkDH102
Tue Feb 26, 2019 12:28 pm
Forum: AIY Projects
Topic: Does Google AIY still work on the Raspberry Pi?
Replies: 7
Views: 739

Does Google AIY still work on the Raspberry Pi?

Well, I tried at the weekend to get AIY running on my Pi3 with an up to date Stretch. I followed some instructions from Feb 2018. No joy. All kinds of errors. So, I then dug out a Stretch image that I had successfully used to control lights and play music etc from Christmas 2018. No joy!!! All kinds...
by MarkDH102
Mon Feb 18, 2019 1:55 pm
Forum: General discussion
Topic: Problems with time ... yet again
Replies: 8
Views: 334

Re: Problems with time ... yet again

Ok. Thanks. Is there a way of removing ntp and going back to the timesyncd service (which caused me issues in the first place)...
by MarkDH102
Mon Feb 18, 2019 1:35 pm
Forum: General discussion
Topic: Problems with time ... yet again
Replies: 8
Views: 334

Re: Problems with time ... yet again

Thanks for that.
There are no entries in the journal. I have restarted the service and it has made no difference.
time1.png
time1.png (12.6 KiB) Viewed 195 times

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