history

The Raspberry Pi is a series of low cost, compact single board computers developed 
in the UK by the Raspberry Pi Foundation in collaboration with Broadcom. Conceived 
in 2008 by Eben Upton to address declining programming skills among students, it was 
inspired by the BBC Micro of the 1980s and aimed to rekindle interest in computing 
education at an affordable price.

Early Development (2006_2012) Initial prototypes appeared between 2006_2011, 
evolving from large test boards to USB stick_sized designs. By August 2011, 
50 alpha boards were functional, running Debian and 1080p video. The first 
commercial model, Raspberry Pi Model B, launched on 29 February 2012 at $35, 
selling out instantly and causing distributor websites to crash. A cheaper 
Model A followed in 2013.

Growth and Diversification (2014_2019) In 2014, the Compute Module targeted 
industrial use, while the Model B+ refined the flagship design. The $5 Raspberry 
Pi Zero debuted in 2015, and the Pi 3 series (2016_2018) added 64_bit CPUs, 
Wi_Fi, and Bluetooth. The Raspberry Pi 4 (2019) brought USB 3.0, dual 4K display 
support, and up to 8 GB RAM.

 command line used (similar to DOS) then later desktop GUI ⭐

os Debian Linux basic commands: ls mkdir cd cp mv rm nano sudo chmod 777 (anything goes)   
grep da* myfile.txt  Global Regular Expression Print

Version	Codename	Debian Release Date	RPI OS Release Date
9	Stretch		June 2017		August 2017
10	Buster		July 2019		July 2019
11	Bullseye	August 2021		November 2021
12	Bookworm	June 2023		October 2023
13	Trixie		August 2025		October 2025
14	Forky		???			???

adding packages apt get update    use google to get examples

kernigan and ritchie at Bell Labs 70s developed c language
linux linus torvalds 90s
unix
Unix was developed in the 1970s at AT&T Bell Labs by Ken Thompson and Dennis Ritchie 
as a proprietary OS for large systems and servers. Linux, on the other hand, was 
created in 1991 by Linus Torvalds as a free, open_source Unix_like kernel, later 
combined with GNU (richard stallman) tools to form complete Linux distributions.

general c compiler (gcc)

gcc hello_pgm    
   
#include 
int main() {
   // printf() displays the string inside quotation
   printf("Hello, World!");
   return 0;
}
                                                 
binary numbers base 2   10 types of people joke

    

https://www.ascii-code.com/ 8 bit

https://symbl.cc/en/unicode-table/ 16 bit
 
                                                                                          ^
serial parallel game ports   subway arriving  0,0,1,0,1,1,0,1 _>    subway platform   00101101   
big endian little endian

pinouts

As data is received (RX) on the input and data is sent (transmitted, TX) on the output, 
from the master's point of view, MISO is its RX pin and MOSI is its TX pin, so:
MISO = SPI_RXD
MOSI = SPI_TXD

(For a slave, this would be reversed)

MOSI	Master Out Slave In
MISO	Master In Slave Out
SCLK	Serial Clock (marching rhythm)
SS	Slave Select (one or more)

SPI Serial Peripheral Interface     Controller/Peripheral    least we could do

GPIO General Purpose Input Output _ like a light switch most of the time
robotics IoT smart house

ADC Analog to Digital Conversion .. Binary search .. Higher or Lower .. Phonebook example

PWM Pulse Width Modulation .. on longer = brighter .. off longer = dimmer

     

     

Difference between GPIO_GEN and GPIO   arcane naming conventions


     
SPI Serial Peripheral Interface

SDR
web SDR
ADC
BBBvsRPi Copilot


           Microprocessors

Microprocessors have no OS. They run a single task, however complex like driving a car.

Evolution of Arduino

The Arduino project began in 2005 at the Interactive Design Institute Ivrea (IDII) in Italy, 
aiming to create an affordable, open-source microcontroller platform for designers, students, 
and hobbyists. The idea was sparked by Hernando Barragán's thesis project Wiring, which 
combined a user-friendly IDE with a ready-to-use circuit board. This inspired Massimo Banzi 
and a small team - David Cuartielles, Tom Igoe, Gianluca Martino, and David Mellis - to 
develop a cheaper, simpler, and more accessible platform.

The name Arduino came from Bar di Re Arduino in Ivrea, itself named after King Arduin 
of Italy. Banzi, a regular at the bar, chose it to honor the place where the idea took shape.

From the start, Arduino embraced an open-source hardware model, using Creative Commons 
licensing to encourage sharing and innovation. The first boards were priced around $30, 
designed to be plug-and-play, and featured distinctive blue PCBs with a map of Italy.

By 2009, the team was refining usability, leading to the Arduino UNO - launched in 
2010 at Maker Faire New York. The UNO marked Arduino's transition from a niche 
educational tool to a global maker movement icon. Key innovations included:

Automatic reset via a capacitor link, removing the need for manual resets before uploads.

Automatic power source selection between USB and external supply.

Robust USB connectors for durability.

A non-rectangular board shape for easier orientation in classrooms.

A refined brand identity with a new logo and packaging.

The UNO's design choices - from usability tweaks to aesthetic branding - helped it 
surpass 10 million units sold, empowering countless beginners to enter electronics. 
Today, Arduino boards power projects from LED cubes to DNA analysis kits, and remain 
central to the open hardware movement.

Example: Basic Arduino Blink Sketch

// Blink an LED on pin 13
void setup() {
pinMode(13, OUTPUT); // Set pin 13 as output
}

void loop() {
digitalWrite(13, HIGH); // LED on
delay(1000); // Wait 1 second
digitalWrite(13, LOW); // LED off
delay(1000); // Wait 1 second
}

This simple program reflects Arduino's philosophy - accessible from day one, enabling 
anyone to bring ideas to life.



Snippet of organ pedals for MIDI keyboard Arduino sketch
...
   pinMode(pedA1, INPUT);digitalWrite(pedA1, HIGH);//20k pullup
   pinMode(pedAs1, INPUT);digitalWrite(pedAs1, HIGH);//20k pullup Bb
   pinMode(pedB1, INPUT);digitalWrite(pedB1, HIGH);//20k pullup
   pinMode(pedC2, INPUT);digitalWrite(pedC2, HIGH);//20k pullup
}

void loop() {
  //send patch for organ   
   Serial.write(0xC0);
   Serial.write(patch);
   //Serial.write(velocity);

   delay(10);//debounce contact
   
   if(digitalRead(pedC1) == LOW && swC1 == 0){
       noteOn(cmd, 24, velocity);//note on
       digitalWrite(led, LOW);swC1=1;//stop repeat
   } 
   if(digitalRead(pedC1) == HIGH && swC1 == 1){
       noteOn(cmd, 24, 0x00);//note off
       digitalWrite(led, HIGH);swC1=0;//stop repeat
   } 
   ...



also PWM (pulse width modulation)

     
   

wordwand magic lantern with arduino UNO

MIDI piano playing Blue Eyes by Elton John with F2 glitch

     
     

// mM3 port for ESP32 - CJC - 8/11/2026 using Copilot and mimicking 16-bit 80s processor for compatibility
// 16 groups * 41-byte rows

#include "Arduino.h"
#include "WiFi.h"

#define MUX0  12
#define MUX1  13
#define MUX2  14
#define MUX3  15

#define AD1_PIN 32
#define AD2_PIN 33

// 128 entries
uint32_t NV[128];
uint32_t II[128];
char TF[128][8];        // enough for 6-byte text + comma
char ROW1[16][48];      // 41 bytes + margin

int i = 0;
int j = 0;

const uint32_t CC = 65535;
const uint32_t SN = 11000;
const char comma1[] = ",";

// ----------------------------
// Format helper
// ----------------------------
void fmt(char *out, uint32_t val, int width) {
    char tmp[16];
    sprintf(tmp, "%0*u", width, val);
    sprintf(out, "%s%s", tmp, comma1);
}

// ----------------------------
// Set 4-bit MUX output
// ----------------------------
void setMux(int v) {
    digitalWrite(MUX0, (v & 1) ? HIGH : LOW);
    digitalWrite(MUX1, (v & 2) ? HIGH : LOW);
    digitalWrite(MUX2, (v & 4) ? HIGH : LOW);
    digitalWrite(MUX3, (v & 8) ? HIGH : LOW);
}

void setup() {
    Serial.begin(115200);

    pinMode(MUX0, OUTPUT);
    pinMode(MUX1, OUTPUT);
    pinMode(MUX2, OUTPUT);
    pinMode(MUX3, OUTPUT);

    analogReadResolution(8);   // 0-255, but we use 0-127 range
    analogSetAttenuation(ADC_11db);

    // NV initialized to zero automatically
    // II initialized to zero automatically

    // WiFi connect here if needed
}


void loop() {

    if (i > 15) i = 0;

    setMux(i);
    j = 8 * i;

    delay(950);

    // Read ADCs (limit to 0-127)
    uint32_t AD1 = analogRead(AD1_PIN) & 0x7F;
    uint32_t AD2 = analogRead(AD2_PIN) & 0x7F;

    II[j+0] = i;

    // ---------------- TP block ----------------
    II[j+1] = AD1;

    NV[j+2] += AD1;
    if (NV[j+2] > CC) {
        NV[j+2] = AD1;
        NV[j+3]++;
    }

    II[j+2] = NV[j+2];
    II[j+3] = NV[j+3];

    // ---------------- AP block ----------------
    II[j+4] = AD2;

    NV[j+4] += AD2;
    if (NV[j+5] > CC) {
        NV[j+5] = AD2;
        NV[j+6]++;
    }

    II[j+5] = NV[j+5];
    II[j+6] = NV[j+6];

    II[j+7] = SN;

    // ---------------- Build text fields ----------------
    fmt(TF[j+0], II[j+0], 2);
    fmt(TF[j+1], II[j+1], 3);
    fmt(TF[j+2], II[j+2], 5);
    fmt(TF[j+3], II[j+3], 5);
    fmt(TF[j+4], II[j+4], 3);
    fmt(TF[j+5], II[j+5], 5);
    fmt(TF[j+6], II[j+6], 5);

    char tmpSN[16];
    sprintf(tmpSN, "%u%s", SN, comma1);
    strcpy(TF[j+7], tmpSN);

    // ---------------- Build ROW1 ----------------
    sprintf(ROW1[i], "%s%s%s%s%s%s%s%s",
            TF[j+0], TF[j+1], TF[j+2], TF[j+3],
            TF[j+4], TF[j+5], TF[j+6], TF[j+7]);

    // ---------------- Display ----------------
    Serial.println(ROW1[i]);
    Serial.print("i=");
    Serial.print(i);
    Serial.print("  j=");
    Serial.println(j);

    i++;
}

     

Microcontroller: Most Basic Stamp 2 (BS2) modules use a PIC or Parallax SX processor

Basic Stamp


raspberry-pi-projects-you-can-do-in-1-hour

10-of-the-best-arduino-projects
dr duino
adafruit
jameco
sparkfun
The best wires for breadboards are 22 to 28 AWG solid core or Dupont


Field Programmable Gate Array (FPGA) - Not quite a microprocessor. 
No running program. Just logic combinations with or without a clock. 
Ladder logic. Start-up sequencer, etc. Data flipflop DFF

FPGA IBM
FPGA Sparkfun


10/24/2026 presentation 2