Capturing Data from remote sensors

Wireless & IoT
1

We use sensors to measure groundwater parameters including level and temperature.

The level is measured by a pressure sensor connected by an optical cable to a translator to a USB port. The data is collected by proprietary software. The locations may be 3-400 feet remote from the PC. We need data that is realtime so we use optical cables. There may be multiple locations monitored simultaneously.

The sensor is battery powered, the optical to USB translator is USB powered.

I want to replace to cable with a RF . The remote transmitter should be battery powered. I want to replace just the USB cable which connects the optical cable to the USB port.

Not sure of the baud rate, the sensor updates once per minute. Does this seem like a viable possibility?

2

what is the interface into the sensor, i.e., is there a conversion of some type between the sensor connection and the fiber optic cable? Is the sensor itself RS232 or RS485 or 20mA or some such?

If so, this is easy.

3

The sensor is optical, the connection is optical, there is a translator to USB.

There is a telemetry system available, $1500 for each transceiver.

http://www.solinst.com/products/datalog … telemetry/

4

I read a bit on their web site.

The issue is this: after translating optical to USB, you have a USB plug, as would plug into a PC, right?

If so, the question is did they use a standard USB protocol (there are many), such as the USB/serial standard. Their web site suggests they want to keep this info proprietary to cause sales of their cellular telemetry transmitters. I’ve done that quite a bit; it’s easy on the cellular data side.

Here’s what I’d try

Call and ask if the USB plug can go straight into a PC’s USB port, and the result is that the USB connection is serial and Windows/Linux normal driver for a “virtual COMn port” is used. If so, this becomes easy.

Before plugging in your device’s USB, get a standard USB to RS232 adapter (widely available, preferably one that uses an “FTDI” chip inside the cable, as FTDI (corporation) drivers are built into Windows 7 and later, and in most Linux systems.

Prove that this USB to RS232 will install in Windows, no driver issues.

Then the USB on the fiber cable, if it too does USB to virtual COMn, might show up in the Device Manager of windows as COMn (like COM8). If so, then all we need for short range (300’ or so), is one of many wireless serial data extenders - of which I know many that plug and go, no software to develop.

5

The USB plug does go straight in the PC and when it does it shows up in the Device Manager as USB Serial Port COM4

6

I tried the USB to RS 232 but could not get a connection, nothing showed up in the device manager.

7

stevesturdevant:
I tried the USB to RS 232 but could not get a connection, nothing showed up in the device manager.

merely pluggin in a proper USB to RS232 adaptor should yield a new COMn device in the device manager list, even with the RS232 plug disconnected.

Some of these adaptors from Asia are crap.

Try to get one that uses FTDI’s chipset internally.

This one says it uses FTDI

http://www.newegg.com/Product/Product.a … 6812156039

you can also find them on FTDI’s web site.

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Since the real cable says COM4, it will be relatively easy to make this wireless…

8

I got another USB to RS232 and it does get a connection on COM 3.