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by mosespi
Thu May 03, 2018 10:06 pm
Forum: General discussion
Topic: UPS for a 3B & WD PiDrive Foundation Edition
Replies: 14
Views: 1466

Re: UPS for a 3B & WD PiDrive Foundation Edition

Thanks Moses, That means that in order to power the WD drive I'll need the UPS to have a 5V ~700mA output to USB in addition to whatever's needed for the pi itself, and another different Y cable to inject power in from both UPS and the supply?? Current cabling: Y Splitter from 3A WD PSU, one leg go...
by mosespi
Thu May 03, 2018 5:00 am
Forum: General discussion
Topic: UPS for a 3B & WD PiDrive Foundation Edition
Replies: 14
Views: 1466

Re: UPS for a 3B & WD PiDrive Foundation Edition

Looks like the ideal diode present in prior models of Pi was removed from the 3B+. My 3B+ does backfeed from the GPIO to the micro-USB, while a 3B I tested does not.

Regards,
-Moses
by mosespi
Wed May 02, 2018 11:29 pm
Forum: General discussion
Topic: UPS for a 3B & WD PiDrive Foundation Edition
Replies: 14
Views: 1466

Re: UPS for a 3B & WD PiDrive Foundation Edition

Hmmm - the official WD supply I have is 3A, and I get occasional lightning bolts with that when I have no other peripherals than the wd drive, and with the pi not working hard on anything other than periodic internet accesses and a little bit of read-write to the drive based on what it reads. I'm n...
by mosespi
Wed May 02, 2018 11:16 pm
Forum: General discussion
Topic: UPS for a 3B & WD PiDrive Foundation Edition
Replies: 14
Views: 1466

Re: UPS for a 3B & WD PiDrive Foundation Edition

A UPS on the 5v GPIO will indeed backfeed power to the microusb connector and on to anything else that is there. Doesn't it depend on the Pi model? From the 1B+ onwards (so 1A+, 1B+, 2B, 3B, 3B+) there is a perfect diode which should prevent backfeeding power from GPIO to microUSB. This is not pres...
by mosespi
Wed May 02, 2018 10:18 pm
Forum: General discussion
Topic: UPS for a 3B & WD PiDrive Foundation Edition
Replies: 14
Views: 1466

Re: UPS for a 3B & WD PiDrive Foundation Edition

Hi all, We had a power outage the other day, which my pi didn't like at all! Is anyone able to suggest a UPS which will: + keep the pi and WD PiDrive Foundation Edition hard drive working long enough to survive short glitches without needing to reboot + when battery getting low, to shut down the pi...
by mosespi
Wed May 02, 2018 9:46 pm
Forum: General discussion
Topic: MoPower UPS version 2 in development
Replies: 5
Views: 897

Re: MoPower UPS version 2 in development

Folks, Some more pictures of the new UPS boards. http://www.allspectrum.com/mopower/MOPOWER-HARDWARE-V2-P2/ I have an extra board that I want to give away to an educator for use in school. If you are a teacher or educator in the US and your Pi project needs some sort of UPS or battery power (solar/e...
by mosespi
Sat Apr 28, 2018 8:26 pm
Forum: General discussion
Topic: MoPower UPS version 2 in development
Replies: 5
Views: 897

Re: MoPower UPS version 2 in development

An update: For those who might want to enclose their Pi the UPS fits in some cases with a little bit of modification. Here is a picture of a 3B+ in a case made by Hammond. Modifications took just a few minutes with a drill and snips, including making holes for the power input (barrel connector just ...
by mosespi
Fri Apr 27, 2018 12:46 am
Forum: General discussion
Topic: Advice required please - School House Point project
Replies: 7
Views: 417

Re: Advice required please - School House Point project

Sounds like you need to run from batteries. As mentioned earlier a Pi is fairly power hungry in it's regular form, at least for most ideas of 'battery powered'. Solar is another option, but not indoors. With external components you can shut down and power up Pi when needed, but this takes 5-10 secon...
by mosespi
Wed Apr 25, 2018 8:10 pm
Forum: General discussion
Topic: Connecting several RPi 3 model B via USB
Replies: 28
Views: 2017

Re: Connecting several RPi 3 model B via USB

There are lots of USB to serial converters you may be able to use. Among those you can go TTL for a few meters, RS232 for a few more meters, or RS422/RS485 for hundreds of meters! RS485 will also give you the capability to have multiple stations on the line too. As for software.. they just generall...
by mosespi
Wed Apr 25, 2018 8:51 am
Forum: General discussion
Topic: Connecting several RPi 3 model B via USB
Replies: 28
Views: 2017

Re: Connecting several RPi 3 model B via USB

There are lots of USB to serial converters you may be able to use. Among those you can go TTL for a few meters, RS232 for a few more meters, or RS422/RS485 for hundreds of meters! RS485 will also give you the capability to have multiple stations on the line too. As for software.. they just generally...
by mosespi
Mon Apr 23, 2018 5:15 pm
Forum: General discussion
Topic: MoPower UPS version 2 in development
Replies: 5
Views: 897

Re: MoPower UPS version 2 in development

Harrie, I am hoping to have hardware version 2 available for public release by the end of June. One note I might not have mentioned, the new version will be sold as an assembled module only, as it not well suited for hand assembly. Prototypes are on the bench and testing is going well. Battery lifet...
by mosespi
Mon Apr 23, 2018 5:26 am
Forum: General discussion
Topic: Industrial Reliability for 24/7 Use
Replies: 34
Views: 4624

Re: Industrial Reliability for 24/7 Use

Some long term reliability information.. I've had a model B rev 2 in continuous operation from early 2013 till now. It's on a UPS and I routinely see uptimes of 300+ days. The SD card installed right now is from 2014 and is setup read only. It is a webcam with pictures and logs stored on a USB memor...
by mosespi
Mon Apr 16, 2018 7:22 am
Forum: General discussion
Topic: DC voltage and current datalogger
Replies: 15
Views: 12831

Re: DC voltage and current datalogger

I've used INA219 modules with good results. They talk to the Pi via I2C. Lots of tutorials on the web. Although I have not tried, you should be able to swap out the current sense resistor with a larger current shunt, maybe even off board.

Regards,
-Moses
by mosespi
Mon Apr 16, 2018 6:48 am
Forum: General discussion
Topic: Driving a single WS2811/WS2812 SMD, not a strip
Replies: 8
Views: 1218

Re: Driving a single WS2811/WS2812 SMD, not a strip

You power these with 5v and drive them with the Pi GPIO at 3.3v right? If so.. I seem to remember the high/low transition of these modules needs to be a fraction of the input voltage.. and it was really close to not detecting the 3.3v of the Pi as a data 'high'. If that is your problem you were like...
by mosespi
Tue Apr 10, 2018 3:34 am
Forum: General discussion
Topic: Pi safe shutdown on poweroff
Replies: 4
Views: 1424

Re: Pi safe shutdown on poweroff

A simple resistor divider might not cut it. You can additionally clamp one of the divider resistors with a zener.. it should protect from spikes in a somewhat well behaved automotive/boat power system. Do remember some alternator/automotive systems can be very dirty and in that case you may have pro...
by mosespi
Thu Mar 29, 2018 11:16 pm
Forum: General discussion
Topic: RPi B3+ powering through GPIO
Replies: 7
Views: 1712

Re: RPi B3+ powering through GPIO

I've have a UPS on a 3B+ that feeds 5v to the GPIO through a polyfuse. I've pulled over 1 amp from the USB ports on the Pi and simultaneously stressed out the CPU for an approx 9-11 watt load on the 5v side (about 2 amps or so). All runs well. A side note: The protection employed by most Pi is a pol...
by mosespi
Tue Mar 27, 2018 10:12 pm
Forum: General discussion
Topic: MoPower UPS version 2 in development
Replies: 5
Views: 897

MoPower UPS version 2 in development

Hi Everyone! I have been working on a new hardware revision (v2) of the MoPower UPS and prototypes are on their way! If you are not familiar, this will be a hardware upgrade of the original UPS which you can find here: http://www.allspectrum.com/mopower/ Here is a sneak peak at the top side of the b...
by mosespi
Sun Mar 25, 2018 11:23 pm
Forum: General discussion
Topic: i2c issues with Adafruit Powerboost 1000C
Replies: 1
Views: 445

Re: i2c issues with Adafruit Powerboost 1000C

I don't believe any of the full size Pi models have anything hooked up to the micro-usb data lines. Also, I can't really see how the USB power input would have any direct interaction with I2C.. unless you have some strange power and/or ground problem somewhere that you are effecting by swapping cabl...
by mosespi
Sun Mar 18, 2018 5:11 am
Forum: General discussion
Topic: 3v3 vrail
Replies: 2
Views: 338

Re: 3v3 vrail

Pcmm, You can add a low dropout regulator to the 5v line to get more 3.3v output. But I have a little trouble believing a 2 ma load (isn't that about what a DS18S20 uses?) is causing you problems. I would look to see if maybe something is wrong with your hookup or a defective DS18S20? Regards, -Moses
by mosespi
Sat Mar 17, 2018 8:43 am
Forum: General discussion
Topic: No anti-static bag for 3B+?
Replies: 47
Views: 7293

Re: No anti-static bag for 3B+?

I'm almost certain they need to be in some sort of anti-static bag/box/container. All the ones I've gotten, and I've purchased a good amount, came in anti-static bags. I even remember one or two that came in that anti-static paper bag looking thing, which according to the logo is anti-static. Funny ...
by mosespi
Sat Mar 17, 2018 8:10 am
Forum: General discussion
Topic: UPS solutions?
Replies: 21
Views: 2867

Re: UPS solutions?

PingoBags, I can see it keeping a bit above ambient if it's well insulated. If needed an additional 1 or 2 watt resistor should keep things pretty warm too in the cold months for lithium charging. You likely won't be charging when the power is out, so no need to power the resistor when the power has...
by mosespi
Fri Mar 16, 2018 6:42 pm
Forum: General discussion
Topic: Pi 3 B+ PoE pinout and technical details
Replies: 4
Views: 12939

Pi 3 B+ PoE pinout and technical details

Hi Everyone, Does anyone know the pinout of the 4 pin PoE connector on the 3B+ ? I'm guessing 2 pins tap into the magnetics on the ethernet jack and the other 2 pins are used to inject 5v back into the Pi? Doesn't gigabit have 4 transformers? Maybe all 4 pins go to the magnetics and 5v gets fed back...
by mosespi
Fri Mar 16, 2018 5:19 am
Forum: General discussion
Topic: New Raspberry Pi model 3B+ 1.4 GHz, 330Mbit Ethernet, 802.11ac, PoE
Replies: 376
Views: 66159

Re: New Raspberry Pi model 3B+ 1.4 GHz, 330Mbit Ethernet, 802.11ac, PoE

Does anyone know if there is US stock anywhere right now? I got an order into Newark, but it looks like they have no stock. Maybe I missed the rush..

Regards,
-Moses
by mosespi
Thu Mar 15, 2018 5:53 am
Forum: General discussion
Topic: UPS solutions?
Replies: 21
Views: 2867

Re: UPS solutions?

PingoBags, Indeed if you need AC power as well, it does change things. What I think you are building is essentially a standard offline UPS (one that 'switches' over to the inverter when power fails). I don't believe such a UPS will wear out the battery or inverter without it being used. I have an ol...
by mosespi
Mon Mar 12, 2018 10:38 pm
Forum: General discussion
Topic: UPS solutions?
Replies: 21
Views: 2867

Re: UPS solutions?

PingoBags, If all you are powering is a Pi.. there is no need for an inverter. A simple diode-OR (look it up) arrangement works pretty well for low power DC applications, no 'physical' switching takes place. Look at the schematic for my UPS in the documentation, it has a similar design. I think your...

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