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That's ok, I have my new products now from a different company and I know I will be much happier using them.  Just curious have you ever been sued?
Because it used a different ethernet library?  You might have to go into that twitter library and change it to work with the ethernet library that works with your ethernet shield.
Generale / Re: Usare stesso pin sda per p...
Last post by djavventura - Today at 09:13 pm
Allora accelerometro: gy-521 per l'accelerometro ;
         barometro: gy-68 per il barometro ;
grazie ancora
I already tested that example and nothing, I am working on it now. Dont know what else i can do
Well, since I didn't actively volunteer for it, it was bestowed upon me, then yes, it can be revoked, I guess.

Just like your membership of this forum.
Displays / Re: ATMega328p sleep mode with...
Last post by bperrybap - Today at 09:10 pm
A schematic of your circuit would be nice to have (you didn't provide one) but since you provided photos, it can pretty much be derived.

Little details really matter.
Not that it matters now, but you had told us that the RTC module contained a LIR2032 but the photos show a module with a CR2032.

Are you really powering your circuit with 4 AA batteries in series like the fritzing diagram is showing?
6v is too much voltage.
Beyond that, the biggest thing I notice is that it seems that what you have hooked up right now is not matching what you previously told us you had connected.

This s/w and h/w is not attempting to turn off the power to the RTC to put it into lower power mode.
And from the photos, there is no wire connecting D7 to the RTC.

In looking at the actual schematic for that RTC module there are some design issues that prevent you from using it "as is" for your application.
The LED (for power), and the charging circuit (which was a bad/broken design) have already been removed but there are some VCC and pullup issues that still need to be resolved.

Here is a link to page with lots information on the subject:
There is lots information there including a schematic of your RTC module and links to other places with additional information.
It is pretty dense so take your time reading.

The key thing to note is about the pullups.
What complicates things is that they are needed but in your application you are using dual voltages for the RTC module (module VCC and backup battery)
The RTC module has pullups on it for i2c and for SQW. These pullups are connected to the RTC module VCC which creates a problem when you use an arduino pin to power the module since when you turn off the power to the RTC module VCC by grounding the signal (which is required to push the RTC into low power mode), the RTC module pullups will now be pull downs since they are now connected to ground.

The page above talks about this and how you will need to make some additional changes to the RTC module in order to be able to power it down and use the SQW signal.
They are not difficult but are required because the module was not designed to be used in lower power mode.

In your case, you can use the AVR internal pullup so no external pullup will be needed on the SQW pin.
Also, the AVR has pullups on the SDA and SCL pins. While they are WAY out of spec, they often do work and it may be worth a try to see if it works without external pullups on the i2c bus signals.
While it most likely will work ok without external resistors on the I2c bus signals using only the internal AVR pullups, keep in mind that it is out of spec so there maybe issues depending on the main battery level, the length of the wires used, and the temperature, so for maximum reliability, you may want to use a pair of 10k resistors.

You also need to address the transistor that you are using to power your servo.
As I mentioned in response #42, you cannot use a 2222 transistor the way you are trying to use it.
The way you are using it can damage the AVR or the transistor.
A NPN transistor works by turning on a switch between collector and emitter when current flows between the base and the emitter.
The important thing to keep in mind is that NPN transistors are current driven. It takes current into the base to turn on the "switch" and the more current you need to switch between collector and emitter, the more current you have to push into the base but you do have to limit the current. The way you have it wired up now, you are not limiting the current so it is overloading the AVR pin.
You need a resistor between the AVR pin and the base transistor pin a 1k resistor would probably be fine.
Keep in mind that the needed current that flows into the base of the transistor is wasted.

Alternatively you could switch to a FET transistor like 2N7000
These work on voltage rather than current.
When you apply a voltage to the gate pin, it turns on the switch between the drain pin and the source pin.

You hook it up like this:
(Device VCC signal connects to VCC)
 (Device GND signal)------------+
 (Arduino Pin)-------------G-|-< (2N7000 FET)

This works the way you were assuming the 2222 worked but it doesn't use/waste any current so it is more power efficient than the 2222.
Not sure where you get parts from but I've been happy with this place for low volume low cost parts like this:

Also, when you add back in the code to turn the power to the RTC module on/off you will need to turn it back on when you wake back up.
The older code that you had was not doing this. While the RTC will work with i2c when running off battery its battery backup power, that isn't what you wanted since I assumed you wanted it to use the main power when being accessed.

Hope that helps.
You are slowly being dragged into the world of having to understand the low level hardware.  :)

--- bill


I was wondering if someone could help.
I have a couple of arduinos I have been sending messages to from my linux computers USB using a python script.
and everything has been working fine.

my computer mother board failed so I have replaced it with a banana pi bit like a raspberry pi.
running the bananian OS which is a minimal debian OS but this computer has no running desktop so I am unable to open the arduino ide there is no x system installed.

I have the arduino software and python software needed installed but I am unable to communicate with the arduino.
the arduino is attached over usb as device
18.051417] usb 2-1: FTDI USB Serial Device converter now attached to ttyUSB0
and /dev/ttyUSB0

but if I run the python script that I have used before.
I get "Trying... /dev/ttyUSB0
Failed to connect on /dev/ttyUSB0"

The python script will try all serial ports. but it is unable to communicate with the arduino board.

but if I use the same board with the same code on my laptop with the same python script everything works fine.

So I am fairly sure its a problem with the bananian operating system. the only difference I can see is on my laptop and my old PC I opened the arduino IDE and selected the board and serial port.
and after that the IDE software was not used.

But with this new OS I am unable to open the IDE program and select the board and serial port.
Is there a way of doing this by command line.

Please dose anyone have any ideas to help me diagnose the problem.



This will be a water injection controller.
Why would you inject water into a running internal combustion engine?
Hardware / Re: problema servo motore
Last post by Super_Mood - Today at 09:09 pm
ho poche conoscenze in ambito elettronico ma buone conoscenze in abito di programmazione, i servo che uso sono i
"tower pro MG995" link:
possono girare sia in un modo che nell' altro e hanno la possibilità di girare a 360° continuo,
uso un arduino uno e una semplice batteria da 9V di quelle che si prendono al supermercato per alimentare i servo , per i servo che si muovono a scatti ho sentito di colegarci un diodo ma non so se faccio bene, inoltre gli unici due servo che ruotano non seguono il programma, prima avevo servo che ruotavano a 180° e funzionava tutto alla perfezione ma erano poco potenti. Sapete cosa può essere? sono sbagliati i servo?
Quello che vorrei fare è un ragno telecomandato
Deutsch / Re: LCD 20x4 (von Saintsmart) ...
Last post by larry_berlin - Today at 09:09 pm

Habe natürlich jedes mal ein Example aus der aktuell installierten Lib verwendet (und zuvor alten Libs weggesichert und IDE neu gestartet).

Und jetzt kommt der Witz, hab jetzt noch eine zweite Lib im Web gefunden, die genauso funktionert bzw. nicht funktioniert (nur 2 x 16 können angesteuert werden) wie eine andere.

Für mich verdichtet sich der Verdacht eines Hardwareproblems. Habe eine neue LCD-Anzeige (gleicher Hersteller) bestellt, wenn die da ist wird diese ausprobiert.

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