• Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

serial port interfacing

Status
Not open for further replies.

vikram Gurjar

New Member
guys. i am doing a project "FUSE BLOWN INDICATOR" and wants to see my fuse status on pc..so connecting the fuse output via serial port.
now is this possible to read input voltage using python or any language???
plz help me out..i am from electrical background
 

RoboWanabe

Member
I think you should be able to do this with a raspberry Pi? and some conditioning circuit around the fuse to make sure you don't damage the Pi. The language of choice for the Pi is python so shoudl be easy
 

KeepItSimpleStupid

Well-Known Member
Most Helpful Member
Well, "fuse blown indicator" can mean a lot of things.

Indicating fuses have a plunger that activates a switch.

A LED across a fuse will "sometimes" work as a blown fuse indicator if all of the other stuff is satisfied. Neon light were used many moons ago.

Breakers with an AUX contact work too.

So, all of these give digital inputs. Your first step.

You don't actually have to read the voltage, Window comparators and power supervisory circuits work too.

So, what are we dealing with 1.8 V or 100 kV, AC or DC or something in between?
 

NorthGuy

Well-Known Member
Long time ago, I used an external modem (should be lots of old ones around). PC can detect whether the modem is powered or not by reading its DSR line. Not very neat, but doesn't require any circuits to build.
 

MrAl

Well-Known Member
Most Helpful Member
Hi,

Probably the simplest way assuming you really want to read voltage and not simply the state of the fuse, is to use a microcontroller that you connect to the circuit under test and the serial RS232 port on the computer. This means you need one single 8 pin dip chip, a cheap opto isolator, and some 1/4 watt resistors.

If you just want to detect the state of the fuse (open or closed) you might get away with an oscillator and a comparator chip or maybe even just a transistor to detect the state.
The oscillator has to be stable however, within something like 2 percent over time. That's so the RS232 does not misread the code, which you would send as 01010101...unless the comparator trips and then that would kill the signal or take out some more bits making them zero. I havent done this but it could work.

The PIC chips have a fairly stable built in oscillator which should work ok once it is calibrated. That would be a more reliable way to do it than with the oscillator, and there's no doubt at all that this would work ok.

The RS232 port on the computer is readable by the Windows API and there are probably examples on the web. This means that you can use any language that can link to the required dll file(s), call their functions, and interpret their return values (includes C and other simpler languages).
 

Reloadron

Well-Known Member
Most Helpful Member
guys. i am doing a project "FUSE BLOWN INDICATOR" and wants to see my fuse status on pc..so connecting the fuse output via serial port.
now is this possible to read input voltage using python or any language???
plz help me out..i am from electrical background

As was mentioned this would go much better if the voltage across the blown fuse terminals was known.

Aside from the data lines on the RS232 port there are a few other pins that can easily be used and read with some very basic software. CTS (Clear To Send) pin 8, DSR (Data Set Ready) pin 6 and DCD (Data Carrier Detect) pin 1 are all able to be used as digital inputs. Given a choice on how to go about this I would just use a digital input, any of those 3 lines with an opto coupler. When the fuse opens (blows) there will be a voltage across the opto coupler input turning it on. The output of the opto coupler will change the normally high logic level on one of those 3 pins to a logic low. From there you can do whatever you want to do.

Been several years but I did write some basic code in VB that reads those pins on the port, The old code could easily be modified to read or do whatever you want to do. If you want a simple demo program just let me know. I do plan to be gone for an extended Fourth of July weekend but other than that I'll be around.

Ron
 
Status
Not open for further replies.

Latest threads

EE World Online Articles

Loading

 
Top