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by BudBennett
Tue Jun 11, 2019 2:22 am
Forum: Automation, sensing and robotics
Topic: 24-bit 16Channel ADC with 16 digital I/O expansion PCB
Replies: 24
Views: 15661

Re: 24-bit 16Channel ADC with 16 digital I/O expansion PCB

Yes, It’s been a long while since I started this thread. There are a lot of other solutions now that might be better. My board has been running continuously over the last 4 years. I recently upgraded the Raspberry Pi to Stretch and there are no problems with the I2C communication. It’s odd that the ...
by BudBennett
Mon May 27, 2019 4:52 pm
Forum: Automation, sensing and robotics
Topic: Detecting 250VAC voltage/current of deep well pump motor
Replies: 45
Views: 17176

Re: Detecting 250VAC voltage/current of deep well pump motor

Hmmm...that solution won't fit in the space that I have available.
by BudBennett
Sun May 19, 2019 11:02 pm
Forum: Other projects
Topic: Small UPS for Raspberry pi
Replies: 19
Views: 1768

Re: Small UPS for Raspberry pi

Mentioned it before? Where in this post? If you can’t solder SMD then you should seriously consider a pre-made UPS. Almost all of the IC solutions created this millennium have been SMD parts. The newest/best stuff is all SMD. —Bud
by BudBennett
Sun May 19, 2019 4:02 am
Forum: Other projects
Topic: Small UPS for Raspberry pi
Replies: 19
Views: 1768

Re: Small UPS for Raspberry pi

Check this out. The UPS is powered by a single supercapacitor that will provide power for about 30seconds, depending upon the size of the supercap and the current drain of the Raspberry Pi. A 100F super capacitor works just fine for a Raspberry Pi Zero W. You will need a larger supercap for a Raspbe...
by BudBennett
Sat May 18, 2019 4:04 am
Forum: Automation, sensing and robotics
Topic: Detecting 250VAC voltage/current of deep well pump motor
Replies: 45
Views: 17176

Re: Detecting 250VAC voltage/current of deep well pump motor

I believe the simplest approach would be to change the two 270kΩ resistors to 120kΩ. I think the circuit would not care if one of the leads was neutral as long as the differential voltage was 110VAC @60Hz. Probably still a good idea to use the Stackpole resistors for safety reasons. — Bud.
by BudBennett
Thu Mar 14, 2019 3:56 am
Forum: Automation, sensing and robotics
Topic: How to register high voltage switching?
Replies: 2
Views: 276

Re: How to register high voltage switching?

I've done this before. Check out this post:
viewtopic.php?p=412103
by BudBennett
Thu Apr 26, 2018 7:35 pm
Forum: Automation, sensing and robotics
Topic: 24-bit 16Channel ADC with 16 digital I/O expansion PCB
Replies: 24
Views: 15661

Re: 24-bit 16Channel ADC with 16 digital I/O expansion PCB

The LTC2499 is S-L-O-W, with a conversion SPS of 7.5Hz. I believe that I stated previously that the ENOB was about 18 bits. It can be improved by averaging multiple samples, if you are measuring slow moving signals like temperature. As for cost...the PCB is around $10. The LTC2499 is $7.25 and the L...
by BudBennett
Tue Apr 24, 2018 9:27 pm
Forum: Automation, sensing and robotics
Topic: 24-bit 16Channel ADC with 16 digital I/O expansion PCB
Replies: 24
Views: 15661

Re: 24-bit 16Channel ADC with 16 digital I/O expansion PCB

Whoa!!! I haven't been watching this posting, since it was nearly 4 years ago. The module is not for sale, but you can order PCBs from OSH park and make one. Unfortunately, I don't have a bill of materials and I removed the schematic from my Dropbox account some time ago. Making this module is not f...
by BudBennett
Sat Jan 13, 2018 1:36 pm
Forum: Other projects
Topic: earthquake sensing - Rasperry Shake and PS3 Eye webcam
Replies: 9
Views: 3240

Re: earthquake sensing - Rasperry Shake and PS3 Eye webcam

BudBennet, What is your Pi seismo setup? Seems to me it should be easy to make Pi ones from old model A, B's. I got enough off those lying around unused now, they need a use instead of just sitting around. I am using a Pi B+. The processor is somewhere between 25-45% occupied with data gathering an...
by BudBennett
Fri Jan 12, 2018 10:06 pm
Forum: Other projects
Topic: earthquake sensing - Rasperry Shake and PS3 Eye webcam
Replies: 9
Views: 3240

Re: earthquake sensing - Rasperry Shake and PS3 Eye webcam

The quake in Honduras registered 30000 counts on my Raspberry Pi powered seismometer. Myanmar registered as well, but is too far away to be much above the noise floor.
by BudBennett
Sun Nov 19, 2017 5:16 pm
Forum: Automation, sensing and robotics
Topic: power management, crash = reboot, power fail = shutdown, power on = boot, script = Python
Replies: 5
Views: 1219

Re: power management, crash = reboot, power fail = shutdown, power on = boot, script = Python

Then check this post about the watchdog. https://www.raspberrypi.org/forums/viewtopic.php?f=29&t=147501 This functionality seems to change as the OS gets updated, but I think that it would still work for what you are trying to accomplish. You can also use systemd to keep track of whether code is run...
by BudBennett
Fri Aug 04, 2017 4:06 am
Forum: Automation, sensing and robotics
Topic: Will this Ups Design work?
Replies: 4
Views: 645

Re: Will this Ups Design work?

From what I could tell by reading the article you referenced, the circuit doesn't do anything but hold up the 5V supply for a few extra seconds. The Pi is not aware that the power has failed until it's too late and will just hard reset when the voltage drops below its minimum requirement. You would ...
by BudBennett
Fri Aug 04, 2017 12:53 am
Forum: Automation, sensing and robotics
Topic: Will this Ups Design work?
Replies: 4
Views: 645

Re: Will this Ups Design work?

I don't think that it will work for you. The supercapacitors will just hold up the 5V supply for an additional 80 seconds before the power fails, so it will still force a hard shutdown on the Pi. UPS is hard to do. A real UPS has to inform the Pi that the power has failed and allow it to perform a s...
by BudBennett
Sat Jul 22, 2017 10:45 pm
Forum: Other projects
Topic: arduino nano as smart power controller for pi zero
Replies: 5
Views: 2234

Re: arduino nano as smart power controller for pi zero

The concept is obvious, the implementation is not. There are a lot of ways to do what you want and a simple Google search for Raspberry Pi UPS will yield a score of them. I have been having fun developing a set of UPS circuits for my own purposes. They are described on my Hackaday.io site: https://h...
by BudBennett
Wed Jun 14, 2017 1:07 pm
Forum: Other projects
Topic: UPS for RPI using single supercap or Li-Ion cell
Replies: 2
Views: 1586

Re: UPS for RPI using single supercap or Li-Ion cell

Thanks for the kind words BMS Doug. We now have working prototypes of the single cell 14500 Li-Ion battery UPS. With a 2A load it could only provide power for about 3 minutes. About 15 minutes with a 1.25A load. And a lightly loaded Raspberry Pi 2B lasted nearly 1.5 hrs! We're moving on to the much ...
by BudBennett
Thu Jun 08, 2017 10:35 pm
Forum: Other projects
Topic: UPS for RPI using single supercap or Li-Ion cell
Replies: 2
Views: 1586

UPS for RPI using single supercap or Li-Ion cell

A few years ago I constructed a simple Uninterruptible Power Supply using a stack of two super capacitors. It has been running continuously since then, but has some peculiarities and is not the most efficient solution. In addition, recent Raspberry Pi versions have gotten more power hungry and I dec...
by BudBennett
Wed May 24, 2017 8:16 pm
Forum: Automation, sensing and robotics
Topic: Controlled Shutdown at Power Failure
Replies: 72
Views: 54519

Re: Controlled Shutdown at Power Failure

Hi Fisek, Things have moved a long way since I posted my first supercap solution, which BTW is still working fine on with the RPi1 attached to the boiler controlling my heating system. But I am now woking with PaulV to come up with an improved UPS system that can provide the higher currents needed b...
by BudBennett
Tue Feb 14, 2017 11:48 pm
Forum: Other projects
Topic: Designing a Printed Circuit Board on a Raspberry Pi
Replies: 8
Views: 4769

Re: Designing a Printed Circuit Board on a Raspberry Pi

I don't like it when people claim to have a better alternative than what I've posted here. But in this case I can't help it. I've been using Diptrace for a few years and have successfully created several PCBs, some of which are quite complex, using the "free" version. Kicad looks like a toy to me. I...
by BudBennett
Tue Feb 14, 2017 6:41 pm
Forum: Automation, sensing and robotics
Topic: Raspi-powered seismometer/seismograph
Replies: 63
Views: 39231

Re: Raspi-powered seismometer/seismograph

State of the art...really? This is from their press release: " Raspberry Shake can detect and record short period (0.5 – 15 Hz) earthquakes; the farther away an earthquake, the less of that range of frequencies can be recorded." The "shake" is using a geophone with a natural frequency of 4.5Hz. If y...
by BudBennett
Sun Feb 12, 2017 5:44 pm
Forum: Automation, sensing and robotics
Topic: Raspi-powered seismometer/seismograph
Replies: 63
Views: 39231

Re: Raspi-powered seismometer/seismograph

Now that my seismometer is essentially finished and working flawlessly in a corner of the garage, I have begun another seismometer project with a friend who has been working on a Lehman seismometer since the early 1980’s. It’s still not quite working yet, so I’ve been pushing him to finish it. Initi...
by BudBennett
Sat Feb 11, 2017 12:10 am
Forum: Automation, sensing and robotics
Topic: 24bit ADC + 16bit DAC ?
Replies: 6
Views: 3042

Re: 24bit ADC + 16bit DAC ?

I can't help you with the DAC. 24-bits is what I use for my home heating system. In reality I get about 18-bits after the noise is accounted for. I use a LTC2499 to read thermistor data. The LTC2499 has a 16-channel mux included, so 4 inputs would not be a problem. I sample 1/minute, process it with...
by BudBennett
Tue Oct 11, 2016 2:06 pm
Forum: Automation, sensing and robotics
Topic: 24-bit 16Channel ADC with 16 digital I/O expansion PCB
Replies: 24
Views: 15661

Re: 24-bit 16Channel ADC with 16 digital I/O expansion PCB

Quick2wire is still available on GitHub: https://github.com/quick2wire/quick2wire-python-api

I don't use their install script but simply put the quick2wire-python-api-master folder in a convenient location and then add the two export lines to my PYTHONPATH as they recommend.

-Bud.
by BudBennett
Sat Jan 09, 2016 2:39 pm
Forum: Automation, sensing and robotics
Topic: Sensing sump pump activity
Replies: 7
Views: 1940

Re: Sensing sump pump activity

There are several posts that relate to what you are trying to do. Take a look at this: https://www.raspberrypi.org/forums/viewtopic.php?f=37&t=54024&hilit=250v+pump It covers both voltage and current sensing. Any circuitry you build/install must take into account possible events (like surges) and fa...
by BudBennett
Sun Nov 01, 2015 9:00 pm
Forum: Automation, sensing and robotics
Topic: Detecting 250VAC voltage/current of deep well pump motor
Replies: 45
Views: 17176

Re: Detecting 250VAC voltage/current of deep well pump motor

That resistor is too big - it is a 2W resistor that has a body that is too large. Digikey will ship to the UK...for 12 GBP, which is like robbery. Can you try to contact the local Stackpole sales office (sales@vtm.co.uk) maybe they can give you some free samples? I tried to find some appropriate hig...

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