Raspberry Pi Forums

grahamed

Does this apply?

https://tecadmin.net/install-mysql-serv ... 9-stretch/

grahamed

So I say want to use MySQL so I can use Workbench and the advice is use sqlite. Yeah sure.

grahamed

Hi What is the latest re MySQL on Pi? I have a working system using Maria installed about a year ago (might be more). At the time I could access it from MySQL Workbench on my PC (Workbench came with MySQL V5.7.25 but I think Workbench had a different number). I could also access MySQL server on my P...

grahamed

There are a number of posts here implying that the OP is little short of an idiot. This is completely unfair - he asked a sensible question about a device he found on line. In fact I feel there is a lot of confusion in the responses here. The device is clearly stated to use phase angle firing to con...

grahamed

The current for the USB-serial is suspiciously large, not more than 50mA and probbly more like 25mA.

The current draw of the devices is the same whether they are pugged into the Pi USB ports or elsewhere; why assume a fully loaded Pi and then count them twice?

grahamed

Variable resistors are there to set voltage, i.e. to conteract volts-drop. hence my question.

Agree with all the rest.

3V3 is fine, could do 5V plus 3 diodes if the mood takes you.

I suggest resistors in series with inputs also good to protect inputs..

grahamed

Variable resistors to set voltage? Current through wiring and switch is less than 330uA. How much volts drop are you expecting?

grahamed

Last week I made a new Pi image c/w MySQL (actually MariaDB but hey). I created the mount points, I edited fstab, I edited my.conf. I rebooted. I checked datadir variable. Shows it is using the USBstick. I imported the data using MySQL Workbench. I read, wrote, etc the data no problem. Left the thin...

grahamed

Rpi3B+, latest Raspian (13-030-2108), updated and upgraded just now sudo apt-get install motion >>> " E: Unable to locate package motion" sudo apt-get install motion-mmal >>> " E: Unable to locate package motion-mmal" (from https://embeddedday.com/projects/raspberry-pi/a-step-further/install-motion-...

grahamed

I use 433MHz a lot. I send the packet maybe 10 times to ensure it gets through at least once. Like the shop-bought remotes and sockets do. My antennae a better than the bitty things within the units. I actually use a PIC micro so timing is not a problem. It's just not terribly good. And that's only ...

grahamed

Hi So this topic is still running and generating more hot air than most. Having read through it again I see there are any number of factual errors, false assumptions, etc which are then corrected, possibly ignored, forgotten about, resurrected, recycled as firelighters, whatever. For my $2/100 - the...

grahamed

Hi Obviously it should not get hot when turned off, but I don't think this is the best device to connect to a 3V3 sysem. i_o characteristics.jpg (http://www.infineon.com/dgdl/irfp3206pbf.pdf?fileId=5546d462533600a401535628d64a1ff0) Unless used in a very hot place the line does not go much below 4V. ...

grahamed

How is this doorbell receiver powered?

grahamed

Hi I guess there might be a Windows program that can copy *x partitions but I am not aware of it. For Windows to copy the partition sparsely, i.e. not copy unused space, etc, it would have to understand the structure. I have used an old Partition Magic live CD but it cannot change the write-protecte...

grahamed

Hi Adjusting the size of the partition is part of the solution. You then have to copy from old card to new card. Windiskimager copies card not partitions so you end up using dd or such and that means having a spare Linux machine to hand. Actually early versions of Windiskimager did not check sizes r...

grahamed

Hi Further findings a USB stick attached during failed SDcard copy was also found to be read-only in the Pi and by Windows, however Windows disk manager recovered it. W10 disk manager says the SDCARD is found, 2 healthy partitions. I can create a new file on the (still read-only) SDCARD boot partiti...

grahamed

Hi drgeoff

I know it's not, that's why I'd really like Raspian to allow expansion to nominal size less 10%. I don't think that will happen either. At this time I do not trust SCARD copier in accessories. I don't like what it does either, copy a live file system... never did that in my day.

grahamed

Hi hippy I think you are correct. I also think it was SDCARD copier what done it. I have no evidence for this excepting that I saw it immediately after a failed attempt to copy a card. But how to undo it? Googling gets many hits re the w/p switch found on full size cards, and many references to Wind...

grahamed

Hi Thanks I never buy such things from eBay - I know people who do and are surprised when their incredibly well-priced card/stick turns out to fill up quicker than its alleged capicity would suggest. Unless two cards are the same size one will be bigger than the other.....irrespective of other quali...

grahamed

Hi again

SDformatter says the card is write-protected.

So I shall buy some more 16G cards.....and hope the new 16G is as big as the old 16G, or has that problem been sorted? - but please do not say use SDCARD copier.

grahamed

Hi OK, thanks for the reply. I was hoping that Linux had somehow become read-only and could be reset. Unless it's an amazing co-incidence it happened during SDCARD COPIER which is a bit worrying, I will use Win32DiskImager to copy off this card, format it with SDformatter, write the earlier backup b...

grahamed

Hi I am quite sure that i have got hold of the wrong end of the stick here; otherwise something rather odd is happening. Well I think it's odd, maybe it is well-known. If I edit a file (such as /etc/rc.local as root), save it, reopen it, see it has changed, reboot, reopen it find it has changed back...

grahamed

Hi The sensor is a current transformer (CT). The CT produces a secondary (output) current proportional to the primary current according to the turns ratio. In this case 1:2000 so 30A will give 15mA in the secondary. The user must choose a suitable resistor to convert this current into a voltage. 1k ...

grahamed

Hi

Where are you connecting the meter? Is it across the battery terminals or across the input of the ADC?

grahamed

Hi

Looks like a K-type thermocouple. If it is then MAX6675 looks like a good solution. The plug is often a clue.

Search found 277 matches

Re: I want MySQL instead of MariaDB

Re: I want MySQL instead of MariaDB

What is the latest MySQL on Pi?

Re: PWM AC Dimmer

Re: What battery do I need based on these components?

Re: connecting multiple magnetic switches

Re: connecting multiple magnetic switches

Re: moving mysql database to a usb drive

motion

Re: Raspberry and Arduino RF Communication range problem with rc-switch

Re: Automatic Car Battery Cut off to prevent rundown andAAA

Re: Controlling two 12 v cabinet locks

Re: using my doorbell to trigger music that wakes me up

Re: Strange things after SDCARD backup

Re: Strange things after SDCARD backup

Re: Strange things after SDCARD backup

Re: Strange things after SDCARD backup

Re: Strange things after SDCARD backup

Re: Strange things after SDCARD backup

Re: Strange things after SDCARD backup

Re: Strange things after SDCARD backup

Strange things after SDCARD backup

Re: Monitoring electrical device activation times

Re: PCF8591P and 50-70mV difference

Re: Two wire temperature sensor