The comment about a robotic arm being built brings to mind the comments from a boss at a recent employer, who asserted that "the only way to design was to create all of the drawings, and then order the parts and have the circuit boards made and stuffed." He considered having any parts on hand as messy and non-professional. He is gone now, also his boss, and with a different manager perhaps the organization will realize that creativity is much more challenging in a sterile vacuum.
As for monitoring data with an audio system, we had a box with batteries, an amplifier, and a speaker for listening to data signals. Once the sound of a good response was known, it was very simple to evaluate test data as to validity and freedom from dropouts. And the evaluation was almost real-time, a great saving of time.
I had a multimeter with a logic probe. It would play a tone when it sensed '1'. Depending on the duty cyle or frequency of 1's in a signal its tone would change. While debugging a uP based system, at the CE of the memory, I could at times tell from the tone of the sound which sub-routine or loop the program is currently waiting in. Different sub-routines would have different memory access rates.
I miss those days, now we get lost in waveform windows.
It is so amazing that simple solutions come in so handy when working on engineering projects. In my previous comment on using cassette player to record bit stream, the model of robotic arm was actually constructed from cannibalised parts of old cassette and LP players. The arm was assembled from aluminium rods and an electromagnet was used to operate the hand, And I had a functional model of a a robotic arm that was remotely controlled from 8085 controller over IR data communication link!
You can visit my blog at: www.uspurtek.com
Infact, I used similar method 25 years ago, when I had to test the operation of IR data communication link between a model of robotic arm and a 8085 based controller. I had interfaced an audio cassette player to record and play the 1200 bps FSK stream. The raw data was used to form a FSK signal in audio band. I recorded the control bytes sent from controller and the responses received from remote robotic arm on the audio cassette as a signature of the different operations performed!
Visit me at:
This really takes me back -- to my first computer, which loaded & saved programs and data from a cassette tape, at baud rates in the audio band. Hearing the bits through the cassette player's speaker was a comforting way to know that things were working -- and when the noise stopped, hopefully that meant your program had loaded successfully!