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by dentex
Sat Feb 07, 2015 6:02 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Sainsmart 16x2 I2C lcd
Replies: 27
Views: 33559

Re: Sainsmart 16x2 I2C lcd

I found that duplicating the line

Code: Select all

lcd = pylcdlib.lcd(0x27,1)
lcd = pylcdlib.lcd(0x27,1)
makes the script to work good every time, but why?
by dentex
Sat Feb 07, 2015 4:20 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Sainsmart 16x2 I2C lcd
Replies: 27
Views: 33559

Re: Sainsmart 16x2 I2C lcd

...well, it works, but if you run the same simple script, as the one above, one time it prints the right text and the next time it prints random symbols and so on, in sequence. Does anyone know why? Sorry I'm a beginner with python, I searched a lot but with no results.

Thanks.
by dentex
Sun Feb 01, 2015 7:30 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Sainsmart 16x2 I2C lcd
Replies: 27
Views: 33559

Re: Sainsmart 16x2 I2C lcd

Thank you very much, my LCD works fine with your example code!
by dentex
Tue Jan 27, 2015 2:49 pm
Forum: Other projects
Topic: Control a dimmable ballast for T8 lamps from the RPi
Replies: 18
Views: 7676

Re: Control a dimmable ballast for T8 lamps from the RPi

Thanks for your detailed reply. Anyway, then I switched over LEDs and PWM to control them, being in the end very happy with the result. It was difficult to find those kind of ballasts and I found LEDs more versatile (think about color mixing) and more affordable. ;) [You may take a look at the non-l...
by dentex
Tue Jan 20, 2015 12:48 pm
Forum: Troubleshooting
Topic: yet one more "no space left on device" issue
Replies: 11
Views: 7157

Re: yet one more "no space left on device" issue

I would like to say a big THANK YOU !!! , for the huge HELP received through this thread.
I discovered the awesome ncdu tool and found where the problem was: up to 2,8 Gb of logs into /var/log.

Ciao!
by dentex
Mon Jan 19, 2015 7:25 am
Forum: Troubleshooting
Topic: cannot execute binary file
Replies: 17
Views: 10554

Re: cannot execute binary file

I've been able to "circumvent" this issue running the root filesystem from an external USB pen drive. There's a good explanation here on the forum: somewhere. Sorry I'm not putting the link now, I'm on the go http://www.raspberrypi.org/forums/viewtopic.php?f=29&t=6125 This way, I've been running my ...
by dentex
Sat Jan 17, 2015 10:08 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: I2C to 16x2 LCD converter - voltage and RPi connection.
Replies: 19
Views: 9047

Re: I2C to 16x2 LCD converter - voltage and RPi connection.

Thanks for the link, I've just had a look: LCD seems the same, while I'm not so sure about the I2C module. I think I'll go for it, anyway.

... and of course you did right to point out the precise definition about connections.
by dentex
Sat Jan 17, 2015 9:31 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: I2C to 16x2 LCD converter - voltage and RPi connection.
Replies: 19
Views: 9047

Re: I2C to 16x2 LCD converter - voltage and RPi connection.

Hello guys,
I've got the same LCD + I2C pack.
I'm sorry I don't understand if it's safe or not to connect the VCC pin directly to a RPi's 5V gpio pin.
Oh another thing (...this stuff comes with no instructions :D ); is the "LED" jumper to enable/disable the power-on LED?

Thanks for any help.
by dentex
Sat Dec 20, 2014 8:05 am
Forum: Automation, sensing and robotics
Topic: 24V to 5V DC to DC conversion
Replies: 21
Views: 20862

Re: 24V to 5V DC to DC conversion

Thanks for the feedback!

Actually I took already the 1st one and the the other converter from 1st post.
;)
by dentex
Fri Dec 19, 2014 9:24 am
Forum: Automation, sensing and robotics
Topic: 24V to 5V DC to DC conversion
Replies: 21
Views: 20862

Re: 24V to 5V DC to DC conversion

Although I'm sure I'll receive them next year. (China is far away :) )
by dentex
Fri Dec 19, 2014 8:41 am
Forum: Automation, sensing and robotics
Topic: 24V to 5V DC to DC conversion
Replies: 21
Views: 20862

Re: 24V to 5V DC to DC conversion

Bought the converter from the 1st post + the same UBEC sold by adafruit (they say has been tested and it's fine).
Yeah. :mrgreen:
by dentex
Wed Dec 17, 2014 1:10 pm
Forum: Automation, sensing and robotics
Topic: 24V to 5V DC to DC conversion
Replies: 21
Views: 20862

Re: 24V to 5V DC to DC conversion

thank you very much Stupotmcdoodlepip,
this kind of calculations about Watts, Volts and Ampere is exactly what I needed, due to me substantially being a newbie in DIY-electronics and RPi-hardware.
by dentex
Wed Dec 17, 2014 9:38 am
Forum: Automation, sensing and robotics
Topic: 24V to 5V DC to DC conversion
Replies: 21
Views: 20862

Re: 24V to 5V DC to DC conversion

Oh, another thing.
Would be bad to connect in series: the 24V main power supply -> the adjustable regulator (from the 1st post) to 12V -> and then the UBEC to have 5V (for the RPi)?
The reason is that I need anyway the 12V and also the UBEC accept 4.75V to 23V input voltage (containing an MP2307).
by dentex
Wed Dec 17, 2014 9:13 am
Forum: Automation, sensing and robotics
Topic: 24V to 5V DC to DC conversion
Replies: 21
Views: 20862

Re: 24V to 5V DC to DC conversion

Thanks everyone for all the inputs! Really useful. Looking at the whole picture, I think I'll use an UBEC. It's cheap, really small (fits easily in my project's enclosure) and can go up to 3A. I found this one (the same item it's on the adafruit store) or this one . While the linked Recom converter ...
by dentex
Mon Dec 15, 2014 5:19 pm
Forum: Automation, sensing and robotics
Topic: 24V to 5V DC to DC conversion
Replies: 21
Views: 20862

Re: 24V to 5V DC to DC conversion

Thanks joan , The regulation screw is something I was thinking about too... is it stable? I also don't know how could the input voltage change. In the mean time I'll also check what is an UBEC. ;) EDIT: found it; so you meant this: http://www.aliexpress.com/item/Universal-RC-Part-Hobbywing-3A-Switch...
by dentex
Mon Dec 15, 2014 5:04 pm
Forum: Automation, sensing and robotics
Topic: 24V to 5V DC to DC conversion
Replies: 21
Views: 20862

24V to 5V DC to DC conversion

Hello. I'm almost ready to use a LED fixture I've built with my RPi (for PWM). I'll be using a 24V, 5A (60W) power supply and three driver (700mA each) to drive some LEDs. So I'll have spare 2,9 amps left. I was thinking about using a step down DC-DC converter to power the RPi with the 5V needed (us...
by dentex
Wed Dec 03, 2014 11:53 am
Forum: Automation, sensing and robotics
Topic: Advise about PWM with LDD drivers
Replies: 9
Views: 3770

Re: Advise about PWM with LDD drivers

Hello again,
just as a follow-up, I've built (but still not tested) a DIY board for those LDD-H drivers.
Later on I'll post also how it is going, if it's working or if I've missed anything. :)
by dentex
Sat Nov 15, 2014 6:08 pm
Forum: Automation, sensing and robotics
Topic: Advise about PWM with LDD drivers
Replies: 9
Views: 3770

Re: Advise about PWM with LDD drivers

Ok, I guess it will work then. I just have to try.

Thanks.
by dentex
Sat Nov 15, 2014 6:02 pm
Forum: Automation, sensing and robotics
Topic: Advise about PWM with LDD drivers
Replies: 9
Views: 3770

Re: Advise about PWM with LDD drivers

Thanks for the reply, I forgot to "watch" the thread.

I meant, in the picture above, under "PWM dimming control" it says H (5V) while below, under "Standard Application" H: >2.5-6VDC or open circuit.

Knowing the gpio pins are 3v3 when "hi", is this the same during a PWM cycle?
by dentex
Wed Nov 12, 2014 12:07 pm
Forum: Automation, sensing and robotics
Topic: Advise about PWM with LDD drivers
Replies: 9
Views: 3770

Re: Advise about PWM with LDD drivers

Thanks for the input, but I was thinking about a high power LED installation and those drivers seems to be proper, from what I read around. They need an external power supply, i.e. 12V or 24V, and will take care of driving the right number of high power LEDs with constant current (depending on the v...
by dentex
Wed Nov 12, 2014 9:55 am
Forum: Automation, sensing and robotics
Topic: Advise about PWM with LDD drivers
Replies: 9
Views: 3770

Advise about PWM with LDD drivers

Hello, I was looking at certain LED drivers by Meanwell, LDD-H : "DC-DC Constant Current Step-Down LED driver" They looks good, considering also they can be dimmed with PWM. About this point, I'm not sure they can be run from the RPi, in regards to the voltage during the HIGH state of the cycle: 201...
by dentex
Wed Nov 05, 2014 2:28 pm
Forum: Automation, sensing and robotics
Topic: Aquarium controller/monitor
Replies: 1
Views: 3081

Re: Aquarium controller/monitor

Hello, I moved the pictures and added the few lines of code to a github repo.
For anyone might be interested: https://github.com/dentex/piac

TODO:
- webserser for information display and remote control (now the shell only is available via ngrok);
- dimmable "main" lighting OR more leds lighting.
by dentex
Wed Nov 05, 2014 2:17 pm
Forum: Automation, sensing and robotics
Topic: Fish Tank Sensor Monitor
Replies: 4
Views: 7387

Re: Fish Tank Sensor Monitor

Hello.
I tried to build my own version too (not related to the fish-pi project).
You can take a look at this post for further info, or head to https://github.com/dentex/piac.
by dentex
Tue Oct 28, 2014 1:52 pm
Forum: Other projects
Topic: Control a dimmable ballast for T8 lamps from the RPi
Replies: 18
Views: 7676

Re: Control a dimmable ballast for T8 lamps from the RPi

Well, now that I was reading something on this 0-10V standard, I think that I had the right answer by iinnovations back in the 2nd post of this thread. From the pdf posted above: [...]Ballasts are the source of the control current. Controllers for this method are variable resistors or an electronic ...
by dentex
Tue Oct 28, 2014 10:06 am
Forum: Other projects
Topic: Control a dimmable ballast for T8 lamps from the RPi
Replies: 18
Views: 7676

Re: Control a dimmable ballast for T8 lamps from the RPi

Thanks again for the informative link.

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