Use of cayenne to automatize laboratory devices


#1

greetings to all

My project is to instrument a laboratory test used in civil engenieering.
so basically i have three water pressure sensors and a flowmeter.
I intend to connect all these devices to a RPI3
my question- is it possible to do this in Cayenne considering that:
(1) i need to make simultaneous measures of all the devices every second (or other time interval that i choose)
(2) i want to see in real time a graph of variables calculated in each reading from several devices (for example, in 6a given time show meanpressure = (pressure 1 + pressure 2)/2
(3) collect the test results in a file

From what ive read cayenne cant yet do it alone right?
what do you recommed as workflow

use node red -> mosquitto -> cayenne?

im a little confused
thanks


#2

Hi @ricardos.geral and welcome to the Cayenne Community.

Right now our Line Chart (graph) widgets can only display one sensor’s data part per widget, so I think you’d have trouble with it alone based on this requirement, yes.

Using our MQTT API you can build a client in many languages including C which could allow for very fast sensor measurements, so your ability to poll simultaneously would be as good as your ability to write software to do so. You could store readings in local variables first before sending to Cayenne (which would necessary add a degree of latency to individually process and transmit each publish statement)


#3

Real Time means latency less than 1 or 2 seconds. Do you need really this time, because as @rsiegel says, you can use MQTT and fetch your data. :slight_smile: