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1  Using Arduino / Installation & Troubleshooting / Re: Mega working fine when usb powered but not when jack. on: July 02, 2013, 05:11:29 pm
So long ago, but for closing. I swapped to a 1 Amp power source and everything was fine.

Regarding monitoring input voltage you could use some resistors. with a couple of them you can build a voltage divider, and then get, for instance, half of your battery voltage. Remember that if you apply more than 5V to an input you can fry it easily. Nevertheless this way is not so accurate, 'cause probably your battery is alive with 9 v and dead with 8. This is from 4.5 to 4 using a voltage divider factor 2. And this .5 volts full scale from top charge to fully discharged may be not enough.

In this case you shoud use a slightly more complex circuit, with a zener diode to get a reference, and an amplifier giving you a 0-5 output with this 0.5 v reading.

Sensing current is more or less the same. you should put a (small) resistor in series with your main 9v supply. This resistor makes a small voltage drop, wich is related to the current flowing. Then, amplifier and... ta-da!.


2  Using Arduino / Networking, Protocols, and Devices / Modbus RTU + Webserver Possible? on: May 23, 2013, 10:27:15 am
Hi All,

I´m working in a tiny webserver. This webserver should be able to report data from a boiler. This boiler has RS485 (modbus rtu 8n1) communication, and I have the whole table. I´m getting into Modbus for first time... smiley-roll-blue

I also have a RS 485 breakboard from sparkfun. I´ve found some libraries wich should be able to work fine, like juan bester´s one:


a) All these libraries are intended for using rx and tx channel (0-1 pins), so, probably, adding a ethernet and willing to use both ethernet and SD card would mess things a lot. That´s why I´ll use a mega 2560. All you know why. Nevertheless, I don´t know how to change those settings in order to select other rxtx channell from mega board.

b) How can I get from boiler just the lines I need at once but not all?

Could you send me some "must read" links to go straight into it?
Any other suggestion?


3  Using Arduino / Networking, Protocols, and Devices / Re: Excellent Arduino Ethernet Shield Web Server Tutorial on: May 23, 2013, 10:15:28 am
Thanks for sharing! You made my day!


4  Using Arduino / Installation & Troubleshooting / Re: Mega working fine when usb powered but not when jack. on: April 12, 2013, 03:49:08 pm
Errr... I´ll try... I was using a spare 9V 400 mA power source from a broken router. Tomorrow I´ll try with the lab power source. I haven´t found any overheating and I can see proper green light in the power leds...
I´ll try. Hope this solves the problem...


5  Using Arduino / Installation & Troubleshooting / Mega working fine when usb powered but not when jack. [solved] on: April 12, 2013, 03:23:50 pm
Hi all!.

I´ve mounted a datalogger with a mega 2560, a gps from libellium and a ethernet shield (just for using the sd card).

I´ve got the system up and running ok, reading and saving properly.
When I power the system with the USB cable, system is working fine (I have a led blinking each time a string is saved), and it´s properly blinking. If I connect serial monitor I can see the live values with no problem and, after that, I can retrieve the values from the *.csv file.


I was packing the system to do some field recordings and when I power the system via the jack (9 v power supply), I have the "ON" led but no blinking led... no readings.. no data. Switch to USB and.. data led starts to blink..

What´s wrong? Is there any bug? I'm puzzled...

Thanks, folks,

6  Using Arduino / Project Guidance / Re: GPS Libellium. Fuzzy Speed readings on: April 11, 2013, 08:10:36 am
Hi all...

I´ve surfed the web a bit and I´ve swapped to tinygps librarie, with much better results.


7  Using Arduino / Project Guidance / GPS Libellium. Fuzzy Speed readings on: April 11, 2013, 06:02:41 am
Hi all.

I am building a datalogger with a libelluim GPS.

I have proper location readings using the examples (TIP: remember to open with old pre-ino soft...) but fuzzy readings of speed. Does anyone have experience with using this shield and logging with it?


8  International / Español / Re: CAN BUS: Red de Arduinos on: December 29, 2011, 06:20:16 am
Gracias mil! Y unas birras!.

Ya iré comentando... tiempo? espero que los dias tengan mas de 27 horas...

9  International / Español / Re: CAN BUS: Red de Arduinos on: December 29, 2011, 03:15:02 am
Hola Igor y compañía. Tremendamente interesante el trabajo que estais realizando.
Tengo previsto, en el momento que tenga algo de tiempo (recurso escaso donde los haya, pardiez..) en meterme con el toyota príus. Si alguien sabe algo (velocidades, mapa de direcciones, etc etc) agradecería feedback.


10  International / Español / Re: Minibloq: Nuevo entorno de programación gráfica para Arduino on: April 13, 2011, 07:34:02 am
Buenísima pinta.

Sería mucho pedir intentar conseguir un estilo de programación similar a KOP? (esquema de contactos usado en la programación de autómatas programables s7). Es totalmente intuitivo.

Un saludo de un absoluto novato,

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