Monthly Archives: June 2014

Separate keyboard: Moving toward a dream

I’ve been dreaming about separate keyboard since I first read someone saying that using it could double typing speed. Think it could be the author of great touch typing courses Vladimir Shahidjanyan who said that. This idea sparked in my head as I always was too lazy and hated to lose time when I could save it. So after a while I bought myself Kinesis Freestyle 2! But as a heavy emacs user I failed to adopt to it. It has very long spacebar and thereby makes it hard to use emacs’ cursor movement commands. One should constantly shift from touchtyping default position (‘asdf’ and ‘jkl;’) to reach Control and Meta keys with a thumb.

From the day I failed to use Freestyle I decided to build my custom mechanical separate keyboard as some great people on Deskthority do.

Having limited access to desired components and knowing little bout how to put them all together, building custom separate mechanical keyboard still remains a dream for me.

But having no progress with this project irritated me. So I decided to hack two ordinary membrane keyboards into separate one. First design I thought of was to just to cut body of two keyboards in a half and then just to bend or roll the underlying circuit thereby freeing some space in between two parts. Next I planned to plug in both keyboards and just to start using them.

While searching for keyboards with small spacebar I studied how keyboards work. Especially how keyboard controller works with a key matrix

It’s not very hard in theory, but what has totally upset me was the possibility of race conditions.

I thought that it will totally break my first design idea, cause say pressing a key on the left-hand keyboard could come after the press on a right-hand though it was hit first.

So I came to the hard decision to decipher which matrix row or column does each controller’s output drive. Then I planned to solder pins of both matrices to one controller thus eliminating race conditions. It was possible, but needed a some preparation and actually paused the progress

The whole project would be on hold now If I have not came to David Kadavy’s post on using split keyboard and to the comment from Ryan Buie Blakeley who said he recently started using TWO keyboards at the same time.

So my first design was actually possible!

All I had to do is to check for race conditions.

Lucky I had two rare ThinkPad Travel UltraNav Keyboards both tenkeyless and having small spacebars. So the whole setup for checking for race conditions looks like on the photo.

Using two tenkeyless keyboards as one split erogonomic keyboard

Took it in my girlfriends photo studio but retouched by myself. Don’t be too harsh on me not having perfect photoshop skills 🙂

And you know what? I’m typing this post on this two keyboards and it feels right. No race conditions, and you get accustomed to it in a few minutes (considering you can touch type).

Another nice feature of this setup is that having touchpad and point stick on both of keyboards makes it possible to use both hands to control mouse poiter. I move it with the right touchpad while pressing left ultranav mouse key.

The next thing to try is to implement the first design by actually cutting the body of two keyboards, lucky now I have two HP keyboards with Japanese layout meaning they have really small spacebars.

For those who does not have any special requirements for keyboard layout like having small spacebar, you can try Kinesis Freestyle or any other split ergonomic keyboard (read Davids post on why one should consider trying).

Hope to try the cut-the-half design in a couple of months, so stay in touch!

EditSomebody already implemented my design idea with cutting body and bending circuit underneath a keyboard. See the project on Instructables. That’s great!

Plus from another Instructables project I’ve learned that Goldtouch V2 Keyboard can easily be hacked into truly separate keyboard. I like it’s layout and spacebar size, so it seams soon I’m gonna buy two pieces ^) one for office and one for home.

SQLDeveloper: Handy user report to generate column names and data types for arbitrary query

I’ve already covered the tough question on converting arbitrary query to clob delimited text (Take 1 and Take 2). The resulting function used a code snippet that produced a list of column names and their datatypes in it’s intestines. Based on that snippet here’s a SQLDeveloper user reports that produces a list of column names and their datatypes for arbitrary query. A result of a report is ready to be used in create (temporary) table statement or insert statement (for target columns) and in many other ways.
Here’s the text of a report:

/* http://stackoverflow.com/questions/6544922/column-names-in-an-empty-oracle-ref-cursor */
DECLARE
  v_ref_cur SYS_REFCURSOR;
  v_cur_handle NUMBER;
  v_count NUMBER;
  v_desc_tab dbms_sql.desc_tab;
  v_statement clob := :a_statement;
  v_print_data_type pls_integer := :a_print_data_type;
  DELIMITER constant varchar2( 5 char ) := chr( 13 ) || chr( 10 ) || chr( 9 ) || ', ';
  PROCEDURE print_desc_tab( a_desc_tab IN sys.dbms_sql.desc_tab, a_print_data_type in pls_integer ) as
    v_data_type VARCHAR2(30);
    v_delimiter varchar2( 30 char ) := '';  
  BEGIN
    dbms_output.put_line( '<pre>' );
    FOR i IN 1 .. a_desc_tab.count LOOP
      SELECT DECODE( to_char( a_desc_tab( i ).col_type ), 1, 'VARCHAR2', 2, 'NUMBER', 12, 'DATE' )
      INTO v_data_type
      FROM dual
      ;
      dbms_output.put( v_delimiter || a_desc_tab( i ).col_name );
      if ( 1 = a_print_data_type ) then
        dbms_output.put( ' ' || v_data_type);  
        case a_desc_tab( i ).col_type
          when 1 then
            dbms_output.put( '(' || to_char( a_desc_tab( i ).col_max_len ) || ' char)' );  
          when 2 then
            if ( 0 != a_desc_tab( i ).col_precision ) then
              dbms_output.put( 
                '(' || to_char( a_desc_tab( i ).col_precision ) || ', ' || to_char( a_desc_tab( i ).col_scale ) || ')'  
              );  
            end if;
          else
          
            null;
        end case;
      end if;
      v_delimiter := DELIMITER;
    END LOOP;
    dbms_output.new_line;
    dbms_output.put_line( '</pre>' );
  END print_desc_tab;
  
BEGIN
  OPEN v_ref_cur FOR v_statement;

  v_cur_handle := dbms_sql.to_cursor_number( v_ref_cur );
  dbms_sql.describe_columns( v_cur_handle, v_count, v_desc_tab );
  
  print_desc_tab( v_desc_tab, v_print_data_type );
  dbms_sql.close_cursor( v_cur_handle );
END;

And here’s the link for user report (hosted on Google drive). Once downloaded it can be imported into SQLDeveloper.