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by philipBC
Fri Mar 15, 2019 2:40 pm
Forum: Troubleshooting
Topic: Ras3 crashes after update
Replies: 38
Views: 4120

Re: Ras3 crashes after update

That update killed the first RPi3 I tried it on. So I didn't update the other 9. I had to completely rebuild my SD card from scratch and re-install non-standard software. Fortunately I do maintain backups. 4 hours of my life I shall not get back. oh. v0.11 has subsequently installed OK, but I am not...
by philipBC
Fri Oct 28, 2016 1:22 pm
Forum: Other programming languages
Topic: Reset 1-wire Bus - DS18B20
Replies: 18
Views: 11258

Reset 1-wire Bus - DS18B20

I have a Pi3 application built in NODE JS which samples readings from 4 DS18B20 temperature sensors. The sensors are connected using all three wires Data, Supply & Ground. I use a single 4.7k resistor to 'pull up' the data line to the 3.3V power line used to power the devices. Initially I used a per...
by philipBC
Fri Oct 07, 2016 1:50 pm
Forum: Other programming languages
Topic: DS18B20 reads -20.5
Replies: 2
Views: 598

Re: DS18B20 reads -20.5

Yes, if I ensure that I don't re-read the same sensor for 1sec (1000ms) then the reading of -22.5 does not occur. I have built my own function (in NODEJS) to interpret the w1_slave file and I now trap readings of ... 85 - occurs upon sensor power reset -22.5 - occurs as described 0, when the resolut...
by philipBC
Fri Oct 07, 2016 1:43 pm
Forum: General discussion
Topic: DS18B20 sensor stops working
Replies: 6
Views: 1366

Re: DS18B20 sensor stops working

I have been working with DS18B20s for some time now using Raspberry Pi 3, Raspbian Jessie Lite and NODEJS. Can you show me the content of the w1_slave file for one of the sensors returning 0. My experience is that getting a zero result comes from the device being in parasitic power mode and not bein...
by philipBC
Wed Oct 05, 2016 5:28 pm
Forum: Beginners
Topic: Dumping nodejs, studying python
Replies: 4
Views: 995

Re: Dumping nodejs, studying python

Check out the nodejs onoff package. I use it to access GPIO pins on a Raspberry Pi 3.
I do all my Pi stuff in nodejs.

https://www.npmjs.com/package/onoff
by philipBC
Wed Oct 05, 2016 3:39 pm
Forum: Automation, sensing and robotics
Topic: PT100 measurement Project Planning
Replies: 7
Views: 3978

Re: PT100 measurement Project Planning

It would be easier to use a DS18B20 temperature sensor, which connects on the 1-wire bus.

... but maybe the challenge for you is building the interface to a PT100 and A/D Convertor.
by philipBC
Wed Oct 05, 2016 3:15 pm
Forum: Other programming languages
Topic: DS18B20 reads -20.5
Replies: 2
Views: 598

Re: DS18B20 reads -20.5

After a little more research, I think the -22.5 occurs when attempting a second read on the sensor as quickly as possible. So a timing issue. The DS18B20 datasheet states the sensor takes 750ms when in mode 7F to carry out the A/D conversion. What is not clear is how the DT Overlay 1-wire driver han...
by philipBC
Wed Oct 05, 2016 10:59 am
Forum: Other programming languages
Topic: DS18B20 reads -20.5
Replies: 2
Views: 598

DS18B20 reads -20.5

I have a several DS18B20 temperature sensors used on RPi3 on the 1-wire bus using the supplied dtoverlay driver. A couple of the sensors sometimes report the temperature -20.5.. ie the first two data bytes in the w1_slave file are 98 FE. 98 fe ff ff 7f ff ff ff 1c : crc=1c YES 98 fe ff ff 7f ff ff f...
by philipBC
Wed Oct 05, 2016 10:41 am
Forum: General discussion
Topic: How is DS18B20 different on RPI 3 vs RPI2 ?
Replies: 9
Views: 2003

Re: How is DS18B20 different on RPI 3 vs RPI2 ?

The latest kernel(s) and releases of Raspbian Jessie have Device Tree enabled. The only configuration required for DS18B20 temperature probes is a line at the end of /boot/config.txt # Enable 1-wire bus on GPIO 17 dtoverlay=w1-gpio,gpiopin=17 Do yourself a favour and add a comment too, so you rememb...
by philipBC
Wed Sep 14, 2016 3:36 pm
Forum: Other programming languages
Topic: [SOLVED] Long setTimeout in NodeJS on Raspberry PI
Replies: 2
Views: 938

Re: [SOLVED] Long setTimeout in NodeJS on Raspberry PI

I thought I was going nuts until I found your post.
Thanks for sharing, Heater.
by philipBC
Wed Sep 14, 2016 12:36 pm
Forum: Other programming languages
Topic: [SOLVED] Long setTimeout in NodeJS on Raspberry PI
Replies: 2
Views: 938

[SOLVED] Long setTimeout in NodeJS on Raspberry PI

I am developing a NodeJS application on a Raspberry Pi 3, running Raspbian Jesse Lite. I stumbled upon a problem with the use of the timer functions setTimeout and setInterval on this platform. If you set an interval of more than an hour (roughly) then the timed event is never triggered ! After exha...
by philipBC
Thu Aug 18, 2016 6:31 pm
Forum: Troubleshooting
Topic: RP3 Raspian Jessie Lite install RTC DS3231
Replies: 2
Views: 3495

Re: RP3 Raspian Jessie Lite install RTC DS3231

In addition my earlier post, I have arranged that my Pi can become a local network NTP server even when it cannot connect to the internet by adding the local RTC to the NTP configuration. In /etc/ntp.conf add to the list of servers the following lines server 127.127.1.0 fudge 127.127.1.0 stratum 10 ...
by philipBC
Fri Aug 12, 2016 2:27 pm
Forum: Troubleshooting
Topic: RP3 Raspian Jessie Lite install RTC DS3231
Replies: 2
Views: 3495

RP3 Raspian Jessie Lite install RTC DS3231

I have spent several days in forums looking for the 'right way' to install an RTC onto my RPi3 which is running the latest flavour of Raspbian Jesse Lite. I have found many of the explanations are out of date due to the arrival of Device Tree support in Rasbian Jessie and I do not want to disable De...

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