All,
I have been reading and reading and would now like some help in making my first project.
Basically I am talking two 4-20 mA signals from two devices and would like to have the data logged on a SD card and have the data from the available on WIFI. I was hoping someone could give me recommendations on a parts list. I see that there are many options and it is somewhat overwhelming.
4-20 ma signals will be powered by the device, no need for the arduino to do this
TIA
What is the bandwidth of the data?
Do you have current-loop conversion hardware?
AWOL:
What is the bandwidth of the data?
Do you have current-loop conversion hardware?
What do you mean by bandwith ?
In regards to loop conversion, I was just hoping to connect the two wire 4-20 wires directly to an Arduino board or convert to 1-5 v with a 250 ohm resistor (i hope that answers your question).
waketech:
What do you mean by bandwith ?In regards to loop conversion, I was just hoping to connect the two wire 4-20 wires directly to an Arduino board or convert to 1-5 v with a 250 ohm resistor (i hope that answers your question).
Not "bandwith" but "bandwidth".
The data rate; the amount of data per second the two signals represent.
AWOL:
Not "bandwith" but "bandwidth".
The data rate; the amount of data per second the two signals represent.
Realistically I would only need the data every min
An arduino managing wifi and ethernet at the same time thats not going to be easy, Id rather choose one of them.
mart256:
An arduino managing wifi and ethernet at the same time thats not going to be easy, Id rather choose one of them.
Let's go with WIFI
Proceed in steps. Plan on days to weeks to get everything working.
Learn Arduino programming by following the basic examples in the development software.
Make the electrical connection to the devices and make sure that you can read and understand the measurements.
Get a wifi shield and learn to connect to the network and send data.
Combine 1 and 2.
THE 4-20MA CURRENT LOOP
After the 250Ω resistor, should use a series resistor (3.3K-10K) to protect Arduino's input. This is because if the sensor generates 24+ mA, there will be 6V+ on Arduino's input. The series resistor will allow Arduino's input protection diodes to do their job without blowing them.
jremington:
Proceed in steps. Plan on days to weeks to get everything working.
Learn Arduino programming by following the basic examples in the development software.
Make the electrical connection to the devices and make sure that you can read and understand the measurements.
Get a wifi shield and learn to connect to the network and send data.
Combine 1 and 2.
Any suggestions on hardware for my requirements, space is not an issues
Instead of an arduino, Id go for a nodemcu board, has wifi and analog and digital io.
I would like to stay with Arduino if possible
waketech:
I would like to stay with Arduino if possible
Do you mean stay with the Arduino IDE, or an Arduino board like Uno?
The NodeMcu boards can be used with Arduino IDE, so its pretty much the same experience as using, say, an Arduino Nano.
I use Wemos D1-mini. These are very compact and inexpensive.
Problem with both the Nodemcu, Wemos and all ESP8266-based boards is that they only have one analog input. There may be ways around this, depending on how your sensors work. Can you give more details, links etc?
Here are some temperature/humidity/pressure sensor circuits i am working on. They report the readings to a website every 15mins, running on li-ion batteries, which should last several weeks despite their small.size.
Paul
PaulRB:
Do you mean stay with the Arduino IDE, or an Arduino board like Uno?The NodeMcu boards can be used with Arduino IDE, so its pretty much the same experience as using, say, an Arduino Nano.
I use Wemos D1-mini. These are very compact and inexpensive.
Problem with both the Nodemcu, Wemos and all ESP8266-based boards is that they only have one analog input. There may be ways around this, depending on how your sensors work. Can you give more details, links etc?
Here are some temperature/humidity/pressure sensor circuits i am working on. They report the readings to a website every 15mins, running on li-ion batteries, which should last several weeks despite their small.size.
Paul
Paul,
As I am new to this my intital assumption was that I could just get a Arduino Mega, slap a few 4-20ma/1-5 volt input boards and then add a WIFI board. Again this is based on the limited knowledge I have. At this point if someone could tell me use this, this and this is kind of what I am looking for...
The transmitters I am hooking up to provide their own power to power the device and they send back a 4-20 mA signal that I would like to log. Because it is 4-20 ma I can convert to 1-5v if needed.
After this project is done I will be looking at something similar to your temp/hum sensors (nice work).
So, you want only advice that matches your preconceived ideas?
Why a mega? You say only a few signals reading, then mega is overkill. Uno plus wifi shield or esp8266 is enough.
Paul: how can you power those esp modules with only 1 batterie? Ive read esp modules need strong power supplies, around 500 ma due power spikes and stuff.
jremington:
So, you want only advice that matches your preconceived ideas?
Yes, as long as what I have pictured is doable, if not then I am looking for guidance.
mart256:
Why a mega? You say only a few signals reading, then mega is overkill. Uno plus wifi shield or esp8266 is enough.Paul: how can you power those esp modules with only 1 batterie? Ive read esp modules need strong power supplies, around 500 ma due power spikes and stuff.
Mega = just what I found looking, not dead set on the idea and cost is no that much of an issue, for example if it goes from 30-40 dollars is not much of a concern. If I went with the uno plus wifi can this handle the two 2-40ma/1-5 v input signals ?
mart256:
Paul: how can you power those esp modules with only 1 batterie? Ive read esp modules need strong power supplies, around 500 ma due power spikes and stuff.
Hard for me to tell with no scope and only a multimeter, but I suspect the current is not higher than 250~300mA max. The 10440 batteries seem to be able to supply this without problems. They are "unprotected" li-ion cells. The WeMos modules have some modest smoothing caps: several 10uF & 100nF.
