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by dgoadby
Sat Aug 17, 2019 5:30 pm
Forum: Graphics, sound and multimedia
Topic: Historical high resolution graphics on the Raspberry Pi
Replies: 35
Views: 3094

Re: Historical high resolution graphics on the Raspberry Pi

This is really impressive and it even looks right. I worked on the 4010's when I was with IBM. Rolls Royce Derby (before they went bust the first time) used them to model components for the the RB211 engine. IIRC these units were actually storage scopes with a vector generator to draw the lines on t...
by dgoadby
Wed Nov 07, 2018 1:48 pm
Forum: Advanced users
Topic: Correct time if Internet connection available or not with RTC
Replies: 4
Views: 505

Re: Correct time if Internet connection available or not with RTC

Thanks Dougie, I will try that. In addition I will use a simple ping to make sure that we are connected to the Internet in any case. If the ping fails then I will assume the RTC has to take priority.

Thanks again.
by dgoadby
Mon Nov 05, 2018 2:43 pm
Forum: Advanced users
Topic: Correct time if Internet connection available or not with RTC
Replies: 4
Views: 505

Re: Correct time if Internet connection available or not with RTC

If we are on just RTC (ie internal clock IC) time then we need to be able to set the time in the first place. Also, RTC chips do drift a little, so there may need to be an occasional adjustment to the current time. Even it we connected to an NTP server once (eg post manufacture) then the RTC will ne...
by dgoadby
Sun Nov 04, 2018 3:21 am
Forum: Advanced users
Topic: Correct time if Internet connection available or not with RTC
Replies: 4
Views: 505

Correct time if Internet connection available or not with RTC

I have a system that may or may not have an Internet connection. I want the system to have the correct time regardless of the Internet connection. The logic I want is something like this: During boot-up: Load date & time from RTC (DS1302 or similar) If Internet connection { get NTP time Update syste...
by dgoadby
Wed May 31, 2017 1:04 pm
Forum: General discussion
Topic: RPI 3 using wifi AP just for local laptop
Replies: 1
Views: 285

RPI 3 using wifi AP just for local laptop

I have an RPi3 system with a LAMP stack installed. I use MySQL for configuration of a data collection system as it is easier, and more flexible, to use PHP forms than writing touch-screen code. Usually my clients access the RPi's on the same network using a PC and this works perfectly. I have a cust...
by dgoadby
Fri Oct 28, 2016 11:17 am
Forum: General discussion
Topic: STICKY: USB boot now working on Pi3
Replies: 543
Views: 255094

Update to my last psting

Update: I bought another USB3 adapter which has the ASMEDIA chipset. And, the good news is it works too. I booted the same SSD and no problems at all. In case I was seeing things I tried all of the other adaptors again and none worked. So, it looks like the ASMEDIA/USB3/SSD solution works every time...
by dgoadby
Wed Oct 26, 2016 12:51 pm
Forum: General discussion
Topic: STICKY: USB boot now working on Pi3
Replies: 543
Views: 255094

Re: USB boot now working on Pi3

The addition of the feature to be able to boot from USB devices is very welcome. However, the implementation seems to have created a firestorm of blog entries by Rpi3 users trying to make it work. Some blogs make it look like a black art to get a RPi3 to boot from USB devices. I have been trying to ...
by dgoadby
Mon Dec 17, 2012 1:43 am
Forum: Automation, sensing and robotics
Topic: Raspi-powered seismometer/seismograph
Replies: 63
Views: 38143

Re: Raspi-powered seismometer/seismograph

It's a version of a fairly standard design called a Shackleford-Gundersen Seismometer. This is a 1975 design but I have updated the electronics and done all of the later improvements. A lot of folks build what is called a "swinging gate" design attributed to Lehman and it works well too but the SG u...
by dgoadby
Sun Dec 16, 2012 12:34 pm
Forum: Automation, sensing and robotics
Topic: Raspi-powered seismometer/seismograph
Replies: 63
Views: 38143

Re: Raspi-powered seismometer/seismograph

Oh yes; I'm still tweaking the mechanics and the electronics to try and get a stable platform. I think I'm about there so the RPi interface is now on the bench. I have a Wifi AP in range of where the seismometer will be permanently sited and a large solar cell designed for charging car batteries whi...
by dgoadby
Tue Jul 10, 2012 6:29 pm
Forum: Automation, sensing and robotics
Topic: Raspi-powered seismometer/seismograph
Replies: 63
Views: 38143

Re: Raspi-powered seismometer/seismograph

All good and gratefully received. I already have the RPi serial port sorted out but I really want to use the I2C interface for capture if possible to simplify the process as much as possible. One option is to use the RPi with I2C to capture, filter and store the data and then the serial interface to...
by dgoadby
Fri Jul 06, 2012 3:23 pm
Forum: Automation, sensing and robotics
Topic: Raspi-powered seismometer/seismograph
Replies: 63
Views: 38143

Re: Raspi-powered seismometer/seismograph

Good to hear from you Paul; thanks for the information. I will see what the local schools are doing too and maybe offer some input to them as we are in a 'quake zone. To your code offer then yes please. I use Python a lot in my day job so I was hoping to keep to a language I have the tools for. I wi...
by dgoadby
Thu Jun 21, 2012 1:02 am
Forum: Automation, sensing and robotics
Topic: Raspi-powered seismometer/seismograph
Replies: 63
Views: 38143

Re: Raspi-powered seismometer/seismograph

Hi, Thanks for your input. I do have the materials for a Lehman but decided on the Shackleford-Gunderson design as it's smaller footprint suited my initial location. As I am in an area the does gets quakes (Gwynedd North Wales) the higher frequency response is something I will have to cater for. Onc...
by dgoadby
Fri Jun 15, 2012 6:02 pm
Forum: Automation, sensing and robotics
Topic: Raspi-powered seismometer/seismograph
Replies: 63
Views: 38143

Re: Raspi-powered seismometer/seismograph

Thanks for the information. I am aware of the Infiltec design but there is no software source so it's going to cost at least $210 + import duties which is a lot more than my parts to-date. However, I do like the use of the MAX7401 filter and may use it as it will save on parts and it is easy to chan...
by dgoadby
Mon Jun 11, 2012 2:48 pm
Forum: Automation, sensing and robotics
Topic: Raspi-powered seismometer/seismograph
Replies: 63
Views: 38143

Re: Raspi-powered seismometer/seismograph

You are right, but, since I live near the sea I am also interested in the changes in the earth tilt due to the tides. To do this I will be monitoring very slow moving data. I also have one to hand as it happens. ;-) The general consensus seems to indicate that we are only interested in frequencies b...
by dgoadby
Sat Jun 09, 2012 3:52 pm
Forum: Automation, sensing and robotics
Topic: Raspi-powered seismometer/seismograph
Replies: 63
Views: 38143

Re: Raspi-powered seismometer/seismograph

I am building a Shackleford-Gunderson Seismometer. I am also proposing to use a RPi to do the data capture and storage with a small HTTP server providing a web-page with recent plots. The route I chose was not to do audio capture but use the I2C interface to an A->D converter IC. I haven't selected ...

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