The great Bob Pease made a nice comment at the beginning of his book Troubleshooting Analog Circuits. He says: «(...) an old test manager I used to work with, Tom Milligan, used to tell his technicians, “When you are taking data, if you see something funny, Record Amount of Funny.” That was such a significant piece of advice, we called it “Milligan’s Law.” A few significant notes can save you hours of work. Clues are where you find them; they should be saved and savored».
In Spanish we have a motto: «cada maestrillo tiene su librillo», which could be (badly) translated as «every little master has his own little book». Today I wanted to share with you two very different and complimentary techniques that I have been evolving during decades of electronic design to record the amount of funny.
Notebook
Paper and pencil
When I am designing, I express myself better with a notebook. My favorite one has an A4 size1 fully white: no lines, no squares, no margins: just white paper.
I like to write with a 0.5 mm mechanical pencil with HB leads. A mechanical pencil frees you about the need to sharpen the pen from time to time and allows continuous work. This thickness is a good compromise between detail and robustness: thinner ones tend to break more frequently.
My handwriting is with (very) small letter and I alternate drawing and writing. I like to write down almost anything except when the ideas are not clear: then I use to write down in separate sheets, most of time those that have already been written by one side. When the idea become clear, I copy to the notebook and reject the paper. This has been a long term fight against myself but it is the only way to centralize all the information in a single notebook.
Sometimes I have to include printed material like datasheets, state diagrams and similar, I cut the paper with scissors and glue to the notebook paper. Once again, I do this to avoid having unattached papers to the notebook.
Frequently I use a blue/red pencil (those that have a color in each side of the pen) when I want to highlight something. I am quite old fashioned.
Content organization
From my colleague Josep, I learned a very useful trick: devote the first page of the notebook to create a page index of the content. Requires a periodic update.
The next few pages are dedicated to some text that I read when I start my working. I use to write down things I have found that help me to be more conscious of what to work for and how to do in proper way. How many times reading few minutes have helped me much in working with happiness and meaning! Even the most insignificant thing worth being done with care and love.
I number every notebook in the cover. I also number by hand only the odd pages in the upper right corner. This allows cross referencing like: «this continues in page 47 of notebook#2».
I try to start every new contend I add with the date of the day. Helps to find forgotten material.
In this respect, I had a colleague, Carmen, who very funny and brilliant engineer and better person that once said: «notebooks are nice but it's a pity they do not support a search function». And this is when I started to use an alternate method I use only when I debug in the bench, not during design.
Computer notes: emacs org mode
GNU emacs is an old fashioned text (ASCII) editor that I started to use when writing VHDL thanks to the advice I saw in a Ben Cohen book. Emacs supports may programming languages an includes a Lisp interpreter that allows incredible things. Later on, I discovered the emacs org
mode. It has an unique capability I have seen in no other text editor: the possibility to hide content selectively at any indentation level. Place at the relevant level, press TAB and it will hide/show the things under this level. When there are hidden content, just a discrete three dots (…) are shown.
Emacs allow to include HTTP links, tables and export to nice HTML, PDF, Markdown (MD) and many other formats.
It is true that emacs has a painful learning curve (I wonder if I could start today) but once you have done the investment, it is a superb tool.
I use emacs as a ship's log book, writing down the daily activity.
Oscilloscope captures
During debugging I take a lot of oscilloscope captures. After trying different alternatives I have decided to use a file naming that is 'scope<number>
' or '<project>_<number>
' like scope123
or SMAUG_ADC_123
. Trying to use a descriptive name tends be useless because description tends to be very long and always insufficient and requires long editing time. Number is an auto increment number that the oscilloscope assigns by itself. It is in the text I write down in the notebook or in the computer editor I can make a large description of the measurement conditions and the conclusions reached.
Using the reference of the project helps much to identify the capture context.
While debugging, either in the notebook or the computer I make continuous reference to the scope capture. See a reference to scope_230
in the emacs screen capture before.
What I always try to do is to name the signals in the display: because of that I always use an small keyboard, permanently attached to the oscilloscope. Alternatively, I write down clearly which signal is connected to which channel.
When I configure oscilloscope to measure a quantity (frequency, level, rise time…), I may capture the screen or not, but I always write down in the log book the value obtained. Sometimes is easier to press the screen capture button but makes much more sense to make the effort to write down the obtained figure. If you need to come back to the written text, the information is where you need.
And above all, if you see something funny, Record Amount of Funny.
In Europe and South America, the ISO 216 standard is very common and very successful and for a very good reason. A0 sizes 1 m2. A1 is composed of two A0, and so on. The height/width ratio is equal to sqrt(2). A4 measures 210 × 297 mm