Suggestion on which board to use for app

Hi Guys,

I am trying to build solar cell + inverter + SMPS voltage monitor.

The inputs are:

1. Solar PV cell voltage and current.
2. Input voltage from PT (potential transformer)
3. Current through CT (current transformer)
4. SMPS Voltage and Current.
5. Inverter status (on/Battery low/overload)

The outputs are:

1. SMPS switch (ON/OFF)
2. Inverter switch (ON/OFF and RESET)
3. RS232 interface
4. Ethernet
5. GPS
6. GSM/RF (for remote logging capability)
7. LCD
8. USB

The main point of this project is data logging ie. to be able to send an
update of the front-end (PV/inverter/SMPS) once every morning, every day
remotely. Also should be able to control the system (nos.1 and 2) remotely
i.e. through internet.

Based on this, board should I use? Any suggestions are welcome.

Thanks a lot for your help.

Ignore the OS for the moment, the issue you have with the FriendlyArm
boards is lack of analog input support (doesn't appear to bring any of the
CPU's ADC pins to an external connector. Only 1 to a variable resistor for
testing) and your project needs 4 minimum.

What I did was build an external PCB with a number of I2C based 16 bit
ADC's installed on it. I used the MCP3424 which has internal reference.
They are nice and stable as long as you apply good PCB rules and filter the
AVCC supply input. 

Using this same idea, this external PCB can also have the GPIO for the
control you need.

Depending on your OS of choice and budget, any of the boards should work
for your needs as they all have GPIO and I2C available on connectors that
you can use to connect to your own board.

GPS and GSM will be via external devices. GPS can be serial and the GSM is
a USB dongle.

Good luck with your project. It sound interesting.

Hi Dave,
Thanks for your response.

So looks like I will be needing the following components:

a. ARM Based ADC IC.
b. MAX232 + all the peripheral circuitry
c. Ethernet IC (ENC28J60 or similar)?
d. GPS: MAX2740 or similar?
e. GSM: SIM900 or similar?
f. LCD off the shelf
g. USB which one should I use?

I also found some great boards by Keil.
(http://www.keil.com/boards/cortexm.asp)

Only thing I didn't see is a GSM. Also not sure if there are analog inputs.

Can you please comment on this?

Thanks for your help.

As you asked this on the FriendlyArm forum I was assuming you were
considering one of the boards here.

Sorry, can't help you otherwise as I know nothing of the others.

As I said, you will need a custom interface PCB to use the boards from
here, but you do get a complete OS and only need to concentrate on the
application. The Keil boards don't have an OS as such so you need to do all
the graphics drivers etc.

One of the little boards here with the 4.3" LCD would suit your needs and
you can choose Android or Linux or CE (not free) as your OS.

As you will need to develop an interface board for your needs, you can
included all the parts needed to interface CT's, Solar PV etc etc. You can
also add a GPS module and connect to serial and lastly RS232 level drivers.

The rest is all part of the FriendlyArm board.

Look what you can get with one simpliest thing for mini2440:
http://www.youtube.com/watch?v=Q2mjBy_Yor4

You can read 4 ADC channels from CON4.
Your PHP script can get parameters and form data logger document.

Finely, you can buy a cheap Android phone and do all your work via IOIO
board. It's easy.

Suggestion on which board to use for app

It is rather difficult to understand your two postings.  What application
do you want to run and under which operating system?