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by Gert van Loo
Sun Oct 15, 2017 11:52 am
Forum: Nederlands
Topic: Ik wil graag een programma starten bij opstarten ( crontab)
Replies: 8
Views: 645

Re: Ik wil graag een programma starten bij opstarten ( crontab)

moet het niet gewoon in init.d gezet worden? Pit Hangt er vanaf wat voor programma gestart wordt en of het ook gestopt moet worden. init.d is bedoelt voor services. rc.local is het eenvoudigst want het heeft de minste regels/condities/voorwaarden. Dit: https://unix.stackexchange.com/questions/18804...
by Gert van Loo
Tue Oct 10, 2017 8:33 pm
Forum: Troubleshooting
Topic: Re-start with three cores corrupts SD-card?
Replies: 11
Views: 533

Re: Re-start with three cores corrupts SD-card?

I was wondering because the times it was going OK I was using a jessie-light image. Just switched back to full blown jessie, edit cmdline.txt: 1/ Removed console 2/ Added maxcpus=3 Save Sudo halt wait until led is off. Remove power, apply power: reboot and image is corrupt!!! Would appreciate if som...
by Gert van Loo
Tue Oct 10, 2017 8:21 pm
Forum: Troubleshooting
Topic: Re-start with three cores corrupts SD-card?
Replies: 11
Views: 533

Re: Re-start with three cores corrupts SD-card?

Did you wait for the 10 flashes to finish before pulling the power?
Good question but yes, I always do.
(I am not that new to the Pi you know, I have been using them for rather a long time. :-) :-) )
by Gert van Loo
Tue Oct 10, 2017 4:18 pm
Forum: Troubleshooting
Topic: Re-start with three cores corrupts SD-card?
Replies: 11
Views: 533

Re: Re-start with three cores corrupts SD-card?

I only tried with 3 CPUs.

I just tried twice more to start and it was OK.
I thought it was unlikely to be a bug as somebody would have noticed by now
but three times in a row made me suspicious.
by Gert van Loo
Tue Oct 10, 2017 11:38 am
Forum: Troubleshooting
Topic: Re-start with three cores corrupts SD-card?
Replies: 11
Views: 533

Re: Re-start with three cores damages SD-card?

I can restore the SD card by re-flashing.

(Changed the title to reflect this)
by Gert van Loo
Tue Oct 10, 2017 9:22 am
Forum: Troubleshooting
Topic: Re-start with three cores corrupts SD-card?
Replies: 11
Views: 533

Re-start with three cores corrupts SD-card?

I changed the command line to use three cores: maxcpus=3. I found that reboot gave no problems but after a full shutdown+power off at the next full re-start the SD-card appears damaged. This has now happened three times once with a different Pi-3. I can't help but suspect very much that there is a a...
by Gert van Loo
Sat Oct 07, 2017 1:46 pm
Forum: Gertboard classic
Topic: Gertboard with Pi2 Jessie
Replies: 3
Views: 476

Re: Gertboard with Pi2 Jessie

The change in port mapping on the Pi2/3
That remark reminded me: On the Pi2 and Pi3 the peripheral base address has been moved!!

On Pi1 it is 0x20000000 on Pi2 and 3 it is 0x3F000000.

gb_common.c:
#define BCM2708_PERI_BASE ...
by Gert van Loo
Sat Oct 07, 2017 9:01 am
Forum: Gertboard classic
Topic: Gertboard with Pi2 Jessie
Replies: 3
Views: 476

Re: Gertboard with Pi2 Jessie

Have there been any changes/updates to the gertboard software, or is there any reason it doesn't work on the Pi2? The biggest change to all The raspberry-Pi I/O has been a while ago when they added a device tree. I'll be honest: I never understood how that worked but you can no longer 'just' access...
by Gert van Loo
Tue Oct 03, 2017 5:18 pm
Forum: General discussion
Topic: Help: Looking for someone to advise on pi schools space gravity project
Replies: 21
Views: 876

Re: Help: Looking for someone to advise on pi schools space gravity project

... can stop the motor by lightly rubbing against it If you use stepper motors there are two ways of 'stopping': with or without power. Without power you can move the shaft. I you want to shaft to stay put you have to keep the motor powered. The problem with that is that the motor coils then behave...
by Gert van Loo
Fri Sep 29, 2017 12:40 pm
Forum: Nederlands
Topic: Ik wil graag een programma starten bij opstarten ( crontab)
Replies: 8
Views: 645

Re: Ik wil graag een programma starten bij opstarten ( crontab)

Ik heb het voor de zekerheid nog eens geprobeerd en zie geen problemen. Dit heb ik in /etc/rc.local toegevoegd: /bin/cat /etc/rc.local >/home/pi/cat_output.txt Zoals je ziet geef ik het volledige pad van ALLE onderdelen. Zowel van het command "/bin/cat" (dus niet alleen maar "cat") als ook de file d...
by Gert van Loo
Thu Sep 28, 2017 12:09 pm
Forum: Nederlands
Topic: Ik wil graag een programma starten bij opstarten ( crontab)
Replies: 8
Views: 645

Re: Ik wil graag een programma starten bij opstarten ( crontab)

rc.local gebruiken is de correcte manier om een programma te starten na boot. (Googelen naar 'raspberry pi execute program on startup' geeft deze link: https://www.raspberrypi.org/documentation/linux/usage/rc-local.md ) 'cron' wordt gebruikt om regelmatig bepaalde taken te runnen, niet voor eenmalig...
by Gert van Loo
Thu Sep 28, 2017 11:50 am
Forum: General discussion
Topic: Help: Looking for someone to advise on pi schools space gravity project
Replies: 21
Views: 876

Re: Help: Looking for someone to advise on pi schools space gravity project

struggling to get the two motors and power all hooked up and controlled. I assume the keyword is 'controlled'. Maybe you can elaborate a bit about what kind of control you are looking for. I have a bit of self interest as developed a motor control board and it can do some nifty stuff requiring no r...
by Gert van Loo
Sun Sep 03, 2017 5:32 pm
Forum: Advanced users
Topic: I2S - Clock trouble
Replies: 11
Views: 818

Re: I2S - Clock trouble

Yep! Sorry I used 26 and 27 not 0x26 and 0x27. My fault.
by Gert van Loo
Fri Sep 01, 2017 1:48 pm
Forum: Advanced users
Topic: I2S - Clock trouble
Replies: 11
Views: 818

Re: I2S - Clock trouble

This would result in addresses 0x20101026 and 0x20101027 being modified, is that right? No, that is wrong (This is where you find out if you know C-code a bit or a bit more :D ). clk is a (volatile) pointer to unsigned (int is implied). sizeof(unsigned) is four, thus adding 0x26 or 0x27 to a pointe...
by Gert van Loo
Sat Jul 22, 2017 8:02 pm
Forum: Gertboard classic
Topic: Gertbot
Replies: 70
Views: 14316

Re: Gertbot

Brych2011 wrote:Everything works like a charm!
Thank you for making the board and all your support,
Bogdan
Thank you.
It is always nice to hear that things work.
Too often there is only silence after my answers.
by Gert van Loo
Fri Jul 21, 2017 4:59 pm
Forum: Gertboard classic
Topic: Gertbot
Replies: 70
Views: 14316

Re: Gertbot

You could try series resistors. I use them for my stepper motors too. What would also be possible is to use a higher voltage (8V) and then make sure you do not exceed a certain mark space ratio (75%). It is a bit more dangerous, but technically perfectly safe, (I know that sounds contrasting). The r...
by Gert van Loo
Fri Jul 21, 2017 5:52 am
Forum: Gertboard classic
Topic: Gertbot
Replies: 70
Views: 14316

Re: Gertbot

What voltage are your motors?
The gertbot needs at least 8V.
by Gert van Loo
Thu Jul 20, 2017 7:19 pm
Forum: Gertboard classic
Topic: Gertbot
Replies: 70
Views: 14316

Re: Gertbot

Is there anyway to fix this? Not until I have some idea what the error might be. I need to think on that a bit. (Actually, I need to think on that A LOT) Can you give me some input about what fluctuations you see? And do you know why if I call "quad_on" command but not use "quad_limit" after that, ...
by Gert van Loo
Wed Jul 19, 2017 7:01 pm
Forum: Gertboard classic
Topic: Gertbot
Replies: 70
Views: 14316

Re: Gertbot

Do you get errors?
The Gertbot increments an error counter when it detects an illegal transition |(e.g. 00 to 11 is illegal)
If so, the most likely cause is that the code changes faster then the 1000 Hz max speed.

(And yes, I am back from my business trip).
by Gert van Loo
Wed Jul 19, 2017 6:40 pm
Forum: Gertboard classic
Topic: Gertbot
Replies: 70
Views: 14316

Re: Gertbot

So do you have any suggestion when using Gertbot with a magnetic encoder?
There is no solution, at low speed you magnetic flux change will be slow.
To use a famous quote: "I can't change the laws of physics" ( https://youtu.be/nfZ12UGiisM?t=23)
by Gert van Loo
Tue Jul 18, 2017 6:58 am
Forum: Gertboard classic
Topic: Gertbot
Replies: 70
Views: 14316

Re: Gertbot

I'll give a longer answer later. I am travelling at the moment. As my understanding when I read from the quadrature encoder, the ouput value should be in the range of 0 to 3200 or (-1600 to 1600) No that is wrong. It gives 3200 per revolution. Thus after ten revolutions the counter is 32000. That is...
by Gert van Loo
Tue Jul 11, 2017 6:08 pm
Forum: Gertboard classic
Topic: Gertbot
Replies: 70
Views: 14316

Re: Gertbot

I think I have enabled the encoder but I can't work out how to read them. You must use the 'quad_read' command. See the example usage in the test_driver.py code. Where could I download the file "test_driver.py"? I could not find it on Gertbot's website. Is there any C or C++ version of it? Thanks! ...
by Gert van Loo
Sat Jun 17, 2017 7:17 am
Forum: Add-ons
Topic: Relay not working as expected
Replies: 16
Views: 1206

Re: Relay not working as expected

You are very likely to be OK as I see a transistor/FET on the board (but I can't be 100% sure unless I have a schematic.) This means it will need only a very low voltage (~1Volt) to switch and thus it will work from 3V3. In that case you also should connect it back to the 5V as on 3V3 it may not wor...
by Gert van Loo
Wed Jun 14, 2017 12:50 pm
Forum: Gertboard classic
Topic: gertbot request for enhancements
Replies: 16
Views: 4240

Re: gertbot request for enhancements

The problem may be in the name. Those encoders are called 'quadrature encoders' See section 3.7 of the manual ( https://www.gertbot.com/gbdownload/man/Gertbot.pdf ): connecting Quadrature encoders. The Gertbot has full support for working with quadrature encoders. You can specify a zero position and...
by Gert van Loo
Sat May 20, 2017 7:29 pm
Forum: Beginners
Topic: STICKY: Using a Gert VGA 666 adapter - [HOWTO]
Replies: 145
Views: 70069

Re: Using a Gert VGA 666 adapter - [HOWTO]

amichel72 wrote:News about how to use gert VGA and joystick controls on GPIO's both?
Not without some type of I/O expander, there are not enough pins.
Some suggestions have been made but you seem to keep asking for the impossible.
You can't get en elephant into a Volkswagen, it has been tried :-)
elephant_vw.jpg
elephant_vw.jpg (55.99 KiB) Viewed 3627 times

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