Python Smart Terminal

From OpenCircuits
Jump to: navigation, search



First beta release, with automatic mode still alpha, code at: GitHub Or better yet email User:Russ_hensel Unless I figure out an easier way to keep git hub up to date I will use some other repository.


Almost all my Arduino and other microcontroller projects use serial communications for a least debugging. And in many cases I pair the Arduino with a Raspberry Pi for a very flexible system. A good serial monitor, or terminal program is useful in this sort of project. Because I wanted features not in most terminals and the ability to program it myself, I started one from scratch using Python.

The program is also designed to be a stand alone data logging, environmental monitoring program. In this case it will kick off and run without an operator. Data will be access over the web. I will largely leave a discussion of these features to another page, but probably about half the code is devoted to these features.

Currently the terminal waits for a cr ( or lf i will check ) until it displays ( or make available for processing ) the received string. This make sense for my application, it help the processing. This may not work best for you, let me know.

So what are the features?

  • Free open source
  • Runs across OSs Linux ( inc Raspberry Pi ), Mac or Windows
  • Python
  • Easily adjusted serial communications parameters
  • Multiple, preloaded with data entry fields.
  • Clear ( erase ) receive area for removal of clutter.
  • Copy all or part of receive area.
  • Programmable
  • Database Interface
  • Easily Modified or Replaceable GUI
  • Parameter file for wide range of modifications of program behavior.
  • Easy to run multiple instances with different parameters.
  • Uses standard Python logging class.
  • Includes some advanced data logging features in addition to database data logging.

A much earlier version of this terminal was described in my instructable [Python Terminal for Cheap Pi Arduino Connection] It may have some information that is useful, but the program has grown a lot since then.


This program is intended for those who at least occasionally develop in Python. I expect that they already run some things in Python and will just add this as an additional project. There is no install program you just download the files, place where you keep your projects and run. A bit more later in this section.

Before you begin to install you should know a bit about the environment that I have used to build, test and run the terminal. If your environment differs too much you may have trouble getting it to run.

I run Python mostly using the install that comes with Anaconda Spyder and often use the IDE it installs. This is not necessary, it is just an nice install that downloads a lot of stuff that technical folks find useful. I have use conda an pip to add to this install and do not know offhand all that is in it. It is Python 2.7. You can look at the include statements to get some idea of what you might need to add. Or you can just keep running it and add the packages it complains about.

Download the files ( I have not decided just how they will be on git hub in at least one form ) Uncompress if they are compressed. The directory structure should looks like this

    .... whatever --|
                    |-- rshlib
                    |-- SmartTerminal

Actually the git hub version does not have rshlib so it should look like:

    .... whatever --|
                    |-- SmartTerminal

Put them in your system making "....whatever" anything convenient for your Python. It should run ( at least to put up its GUI ) by running Note that there may be a certain amount of left over, dead code, in the directory I am cleaning out bit by bit, someday it may be nice and neat. For now if you want to tinker look at the design info below first.

Run it until it stops complaining about dependencies ( in the console ), after that ( and perhaps even before ) the GUI should come up. You are installed.

I have run the program on both Windows 10 and Rasperian on a RPi. It should work in most OS's. Let me know about issues.

Some parts of the program think that mySql is available. It should run fine without it ( there will be a message or two in the console ), untill you try to use the database then it is not so gracious. Straight ahead use as a terminal does not use the database.

Configure to Run


Basic configuration of comm parameters like port, baud rate .... is all done in a file called It seemed easier to simply use a Python text file instead of some other format like an ini file. Pretty much all the file does is set instance variables in itself. It is used by the program controller ( smart_terminal.SmartTerminal ) to create an instance of Parameters and then the values can be used. Save the original (, maybe I will include a backup maybe not ) in case you mess it up too much.

I have made yet another pass to clean up and comment the code in parameters. Let me know if you have issues. You should understand some values are being phased out but may still have some implementation and some may be coming in and have little or no implementation. The comments should let you identify these situations.

Parameters starts out with some "meta" parameters. These are defined early in the creation of the objects and may effect other values. In any case you can always define a value twice, the last one always wins. The most important meta parameter is mode, you should not change it from self.mode = "Terminal" unless you understand the implications or do not mind going on a ride.

All the com port values are defined in pretty much one place, find it ( say search on "baud" ) an change it to what you need.

Command Line Arguments

If you run with the command line parameters=paramaters_b then after the regular parameters file run, the system looks for and uses that to override values that you might want to tweak ( or completely redo. There are two examples in the directory follow the pattern in them and you should be fine ).

This can be especially useful if you want to run two copies connected to different ports and possibly running in different modes. In this case it is also nice to change ( its in parameters ) the icon and color for each instance of the program. You can write or use the little bat file to start them ( although this leaves a dos console hanging around ) Command line arguments can also be placed in shortcuts. In either case they may take some tweaking to run in/from your file locations.

The above mostly applies to Windows, but the program run fine with Linux ( including the Raspberry Pi ) and I suppose the Mac. Of course the .bat file and shortcuts will not work, but similar facilities exist in the other OSs.

Running It

When you run it it should open a windows a lot like the picture Smart Terminal GUI. Errors may show up in your Python console or the log file ( look in for the name of the log file, typically self.pylogging_fn = "smart_terminal.py_log" ). The most likely errors will point to missing Python modules like pyserial. You should install with pip ( or conda if using Spyder ). Let me know how it goes.

Normally the terminal does not open the com port until you press the <Open> button. The parameters are displayed in the GUI if you do not like them ( for example when you press the <open> button the port open status changes to "open failed", not the desired "open" ) you can shutdown, edit and restart. There is a simpler way.

  • First configure to know the name of a text editor on your system. For mine this is one of:

self.ex_editor   =  r"leafpad"    # linux and pi

self.ex_editor   =  r"D:\apps\Notepad++\notepad++.exe" # for windows.  

It is set up to auto switch between the two os to make copying the whole program back and forth between the windows and linux a bit easier.

  • Now when you run it the button <Edit Parms> should let you edit the file. Edit it and save.
  • Hit the <Restart> button. In a flash the program should restart with the new parameters.

..... more here soon ......

Notes on the Code

In some ways I am proud of the code, it was sometimes a slog, and I had to learn a lot of Python to get it going. On the other hand it kind of sucks, it has lots of dead code, ass backwards was of doing things, poor naming...... There is also a good bit of code on features that I am adding, but that is unfinished. Until I loose interest in it it will probably improve. However, adding features is more part of the life of a programmer than polishing old features; making something better that seems good enough is not always the priority it should be. If you do not like it, mostly keep it to yourself unless it is accompanied by an offer to improve it. I do not need ideas, I need time. That said if you think you have a helpful comment contact me, my page will tell you how: User:Russ_hensel


These notes are here so you can more easily modify the code. Contact me Russ Hensel if you need additional help.

Before modifying the code it is best to understand how it works. Here is an overview of the general plan, details can be filled out by reading the code.

The architecture is called the model view controller or MVC. The class SmartTerminal ( in ) could be viewed as the main class. To run the program run its file ( see code at end of file) SmartTerminal is the controller in MVC it is responsible for all overall control, it directly or indirectly creates all other program objects.

The view component is called GUI ( in ). It creates all the visible components, and relays user input to the controller.

The model component is the component that actually does the communication it is called RS232Driver ( in ) and like the GUI is controlled by the controller.

The GUI is not allowed to directly communicate with the model and vise versa. Thus you can unplug them from the application and plug in new components. Don't like the GUI? You could modify mine, or you could make a modification and choose which one to use. This is sort of like a skin for an application. You can even set up to run with no GUI at all. The RS232Driver like the GUI easy to remove and replace in the program, its use has been parameterized in to the Parameter object, so to use SPI instead of RS232 all we have to do is write an SPI object and change the values in Parameter.

Two other important components are called Logger ( in ) and Parameters ( in ). The controller creates one of each, and make them available to the other components. The other components can interact with them, and uses them respectively for logging events, and getting access to parameters ( those aspects of the application that are particularly easy to change ).

The application is pretty much single threaded running in a Tkinter mainloop. To make it responsive to both the GUI and its processing it uses a psedo event loop or a polling subroutine that is implemented in SmartTerminal.polling(). This is where data is received from there comm port. The frequency which it is called is set in parameters, the relatively low rate of 100 ms between calls ( .1 sec ) seems to give a perfectly responsive application in most cases. I have run it as fast as once every 10 ms. Have not tried to find a limit.

The big pending development is to make the terminal interact with an Arduino to collect and log data. This code is in place in a pre alpha stage. I can get it to work for me, but it is still not ready for even non prime time. I will write a document on how to use this code for those who may want to plan around with it.

Additional Info

Personal tools