For the logging of data I was originally thinking of running a loop and
constantly sending messages. Then measuring the current consumption with the
multimeter and getting some average over 20 sec. The other option - with the
current sensor would be to do a measurement every 50ms for 20 sec and send
every measurement from the sensor over the serial to my laptop. I might be
approaching this from the wrong side... I like the idea of using a button to
build and send messages. I don't consider myself expert in electronics, but
here is how I was envisioning this in my head (see attached
ProjectDiagram.png). Arduino 3 would be used purely to utilize the current
sensor. It would measure the current consumption of Arduino 1 then the current
consumption on Arduino 2; hence the dashed lines.
Example setup and run (purely theoretical) for measuring current consumption on
Arduino 2:
Arduino 3:
SETUP
set pin 11 as Output (Arduino 2 pin 12)
set pin 12 as Input (Arduino 2 pin 11)
LOOP
if some event (button press or input from Serial) occurs
set pin 11 to HIGH (to start Arduino 2)
start measuring current on Arduino 2
if pin 12 is HIGH
stop measuring current on Arduino 2
set pin 11 to LOW
Arduino 2:
SETUP
set pin 11 as Output (Arduino 3 pin 12)
set pin 12 as Input (Arduino 3 pin 11)
LOOP
if pin 12 is HIGH
read sensor data
construct message (character string or object depending on the method
being tested)
send message
set pin 11 to HIGH
delay(?) not sure for synchronisation???
else
set pin 11 to LOW
Throwing this aside I must admit I'm not familiar with the functionality of Red
Pitaya, but from what you've written it might work in place of Arduino 3 in my
design.
Regards,
Ventsislav
________________________________
From: Robert McWilliam <r...@allmail.net>
Sent: 17 November 2015 13:47
To: Tanev, Ventsislav; 57north-discuss@lists.57north.co
Subject: Re: [57north-discuss] Missing component
On Tue, Nov 17, 2015, at 12:37, Tanev, Ventsislav wrote:
I was originally hoping to measure the current consumption with a multimeter,
but the current consumption might fluctuate too quick for me to register
meaningful data. What I believe will work is to measure how much power will be
consumed with a current sensor (ACS712) and log the data. However as I don't
have such sensor and the estimated delivery for one is way past my deadline I
was hoping that you guys have 1 I could borrow.
In all cases any feedback would be greatly appreciated [??]
I think the current sensor chips are overkill for what you're doing here (and
the power changes you'll be looking at will be a few orders of magnitude from
what they're designed for so might be lost in the noise): the devices you're
looking at are powered by low voltage DC; just put a known small resistor in
the power line and measure the voltage across it.
The (slightly more) complicated part will be logging the data. What kind of
time frame are you talking about for the building and sending the
message/object? I expect it's much shorter than you have any change of getting
with a multimeter, pencil and paper. I have a Red Pitaya[1] in the space that I
think would work for this. It could be set up to grab voltage readings at
whatever period is needed (well, probably: max sample rate is 125MS/s) based on
trigger on the other channel, then put one channel over the resistor and the
other to a button that's also connected to the pi/arduino to trigger message
building and sending. Can have the data output to python or matlab (or some
other places) for further processing.
Robert
[1] http://redpitaya.com/
--
Robert McWilliam r...@allmail.net www.ormiret.com
Cleverly disguised as a responsible adult.
_______________________________________________
57north-discuss mailing list
57north-discuss@lists.57north.co
http://lists.57north.co/listinfo/57north-discuss
