Posts: 17
Joined: Tue Mar 22, 2016 2:36 pm

I2C / Nano / LCD / Real Time Clock

Wed Mar 23, 2016 2:39 pm


I'm looking for some comments on a board I've created which links a Raspberry Pi and Arduino Nano, it uses a barrel connector for power supplied (I prefer these as have spare adapters lying around but not so many micro usb), it's protected against voltage being applied the wrong way around, takes DC in the range 9v - 20v (depending on choice on onboard voltage regulator / switched mode power supply) and is capable of powering a Raspberry Pi (used model b so far) via the GPIO header pins.


For stand alone projects where the code has been written to the Nano (and the Raspberry Pi is no longer connected), then it would be possible to power this using a cheap 7805 voltage regulator alternatively, a drop in switched mode power supply can power the Raspberry Pi, Nano & interface board. There are 2 couple of jumpers to allow current usage to be seen (using a multimeter).

I2C header pins are available to connect a popular RTC (3231) to both the Nano and the Raspberry Pi and also to connect common 5v LCD's (1602/2004) to the Nano via serial interface boards that piggy back onto the LCD's.

The Raspberry Pi and the Nano can communicate over USB and also using the GPIO 14(TX) and 15(RX) pins. When connecting via GPIO pins 14 & 15, voltage level shifting is done so that 5v signals do not reach the Raspberry Pi.

The board is the same size as a Raspberry Pi, with mounting holes (although spacers are required) but the Raspberry Pi and board can obviously be linked with a suitable ribbon cable, in which case, should work with other models too.

The board also has connectors in the form of Arduino Uno shield (not present in the image above) but not done much testing yet with Arduino shields but SHOULD work.

The Nano in the picture was programmed from a Raspberry Pi that it was mounted on top of using arduino 1.0.5 environment, the Nano is reading the time from the RTC module in the picture (to the left of the 2 green LED's), this can be removed, rotated 180 degrees and attached to the pins further left marked "jRTC (Pi)", which allow the clock to be accessed from the Pi.

I have a few other ideas for what might be added - this isn't the first version !

What do you think ?

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Posts: 335
Joined: Wed Feb 03, 2016 3:36 pm
Location: HU

Re: I2C / Nano / LCD / Real Time Clock

Wed Mar 23, 2016 4:33 pm

I am also thinking to buy a uC-board; but ST-401. It has a lot of more efforts, than arduino. But I have been asking myself what is it for? Do I really cannot solve my idea with raspberry and I need a less efficient stuff? The answer is always no. All this thing can be solved by raspberry itself or it does not really a good idea.
on a Raspberry B+ with whezzy, two Zero with Jessie Light

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