Electronics Lab for the .NET Developer

Project-based lessons that take you from blinking an LED to buttons, sound, servo control, analog sensing, and ultrasonic distance measurement — all in C#, with the Visual Studio debugger attached to real hardware. Set a breakpoint and the board stops with it. Hover a variable to read a sensor.

If you can write a loop and a method, you're ready. No electronics background needed, no soldering, no new IDE.

This page covers everything you need before the first lesson: setting up your PC, getting to know your board, and the wiring basics every lesson builds on. Already comfortable with breadboards? Skim your board's pins and jump straight in.

Choose your board

Every lesson works on both lab boards — the wiring and the code are the same except for pin names:

• FEZ Flea — stamp-sized, plugs straight into the breadboard.
• FEZ Bit — adds a 1.8" color display, WiFi, and on-board buttons and buzzer. Plugs into an adapter board next to the breadboard.

Wherever the two differ, lessons show a FEZ Flea / FEZ Bit switch like the one below. Pick your board once — every page remembers it.

FEZ Flea

You're following along with the FEZ Flea. Pin names look like PA3, and in code FEZFlea.GpioPin.PA3.

FEZ Bit

You're following along with the FEZ Bit. Pin names look like P0, and in code FEZBit.GpioPin.P0.

What's in the kit

FEZ Flea

• FEZ Flea — running TinyCLR, with headers fitted
• Solderless breadboard
• USB-C cable

FEZ Bit

• FEZ Bit — running TinyCLR, with a 1.8" color display and WiFi
• Solderless breadboard with a FEZ Bit adapter board
• USB-C cable — for the FEZ Bit
• Micro USB cable — for powering the adapter board

Both kits include the same parts:

• HC-SR04 ultrasonic distance sensor
• Analog joystick (2-axis + button)
• Color (RGB) LED module
• Positional servo motor
• Rotary sensor (potentiometer)
• 4× colored pushbuttons
• Piezo buzzer
• Light sensor (photoresistor)
• 6× LEDs
• 10× 220 Ω resistors — for LEDs
• 5× 27 kΩ resistors — for pull-ups and pull-downs
• 10× pin-to-pin (male-to-male) jumper wires
• 10× pin-to-socket (male-to-female) jumper wires
• Zippered case

Set up your PC

Follow Getting Started to install the tools, load the TinyCLR firmware, and run the starter project. Come back here once the on-board LED is blinking — that proves your PC, the IDE, and your board are all talking to each other.

note

TinyCLR development requires Windows. The lessons use Visual Studio (any edition, including the free Community Edition) for screenshots and shortcuts. VS Code works too — the debugging keys (F5, F10, F11) are the same.

Get to know your board

Each pin has a name you use in code, and a set of functions that tell you what else it can do. Lessons tell you which pin to use — this is the map to find it.

Function	What it does	First used in
GPIO	Digital input or output. Every signal pin can do this.	Digital Output
PWM	Generates pulses — for dimming LEDs, mixing colors, making tones, and driving servos.	Breathing LED
ADC	Reads an analog voltage — for knobs, light sensors, and joysticks.	Analog Input
I²C, SPI	Buses for displays and sensors.	Displays
3.3V, 5V	Power for the parts on your breadboard.	Analog Input
GND	Ground — the 0 V reference every circuit returns to.	Digital Output

FEZ Flea

The white boxes are pin names (PA3 → FEZFlea.GpioPin.PA3 in code); the colored labels are functions.

Function	FEZ Flea pins
GPIO	PA0, PA1, PA2, PA3, PA4, PA5, PB8, PB9, PB13, PB14, PB15
PWM	PA1, PA2, PA3, PA5, PB8
ADC	PA0, PA1, PA2, PA3, PA4, PA5
I²C	PB9 (SDA), PB8 (SCL)
SPI	PB15 (MOSI), PB14 (MISO), PB13 (SCK)
Power	3V3, 5V, GND

On the board: a user LED (FEZFlea.GpioPin.Led) — the one you blinked in Getting Started — and an LDR button for loading firmware.

Setting up: push the Flea into the breadboard so it straddles the center gap — its two rows of pins on opposite halves. That way every pin gets its own row, and no two pins are shorted together. Parts connect by sharing a row with a pin, or with a pin-to-pin jumper wire.

Power: the single USB-C cable does everything — loads your code and powers the board. The Flea's 3V3 and 5V pins power the parts on your breadboard.

Full specs and the schematic: FEZ Flea.

FEZ Bit

Pins on the edge connector are named P0–P16 (P0 → FEZBit.GpioPin.P0 in code).

Function	FEZ Bit pins
GPIO	P0–P16
PWM	P0, P1, P2, P3, P14, P15
ADC	P0, P1, P2, P3, P4, P9, P10, P13, P14, P15
I²C	P20 (SDA), P19 (SCL)
SPI	P15 (MOSI), P14 (MISO), P13 (SCK)
Power (adapter board)	5V, 3.3V, GND

On the board: a user LED (FEZBit.GpioPin.Led), a buzzer (FEZBit.GpioPin.Buzzer), buttons A and B plus four direction buttons, a 1.8" color display, and WiFi. The lessons use the breadboard parts so they match the Flea — but you're free to try the on-board versions too.

Setting up: slide the FEZ Bit into the adapter board's edge connector, display facing up. The adapter brings every pad on the FEZ Bit out to a row of male header pins next to the breadboard. Connect a header pin to a breadboard row with a pin-to-socket (male-to-female) jumper wire — the socket end goes on the header pin.

Power: the FEZ Bit kit uses two USB cables:

• USB-C → FEZ Bit — loads and debugs your code.
• Micro USB → adapter board — powers the adapter's regulator, which provides 5V and 3.3V on the header for the parts on your breadboard. It powers the FEZ Bit too.

While you're coding, plug in both. When you're done, unplug the USB-C cable — the adapter's micro USB cable alone keeps your project running.

tip

Power breadboard parts from the adapter's 5V and 3.3V pins, not the FEZ Bit's own 3V pad. The FEZ Bit's regulator is sized for the board itself; the adapter's regulator is there for your circuits.

Full specs and the schematic: FEZ Bit.

How a breadboard works

A breadboard lets you build circuits by pushing parts and wires into holes — no soldering. Inside, metal strips connect certain holes together:

• Rows of five. Each short row of five holes (for example, a–e in row 10) is connected. Anything plugged into the same row is wired together.
• The center gap. The channel down the middle separates the two halves. Row 10 a–e is not connected to row 10 f–j.

• Power rails. The long strips along the edges, marked + (red) and − (blue), run the length of the board. Connect them to 3.3V and GND once and every part can reach power from anywhere.

tip

On some breadboards the power rails are split in the middle — a gap in the red and blue lines is the giveaway. Bridge the halves with a short jumper if you need power along the full length.

Jumper wires

• Pin-to-pin (male-to-male) — for connecting holes on the breadboard to each other.
• Pin-to-socket (male-to-female) — for modules with header pins, like the distance sensor, joystick, and servo — and for the FEZ Bit adapter's header pins.

Wire color doesn't affect the circuit, but a habit makes circuits easier to check: red for power, black for GND, other colors for signals.

Parts you'll meet first

LEDs

An LED only lights when current flows in one direction:

• The longer leg is the anode (+). It connects toward the pin.
• The shorter leg — next to the flat edge of the LED's rim — is the cathode (−). It connects toward GND.

Put one in backwards and it simply stays dark — no harm done. Flip it around.

Resistors

Resistors limit current. They have no polarity — either direction works. The colored bands encode the value; the kit includes two values:

Value	Bands (4-band)	Used for
220 Ω	red · red · brown · gold	Every LED — 10 in the kit
27 kΩ	red · violet · orange · gold	Pull-ups and pull-downs for inputs — 5 in the kit

Each lesson tells you which value to use and why.

Wiring habits

These five habits prevent almost every beginner mistake:

1. Unplug USB while wiring — both cables on the FEZ Bit. Plug back in when the circuit is complete.
2. Never connect 3.3V or 5V directly to GND. That's a short circuit.
3. Never connect two pins that are both outputs. If one drives high and the other low, the chip can be damaged.
4. Always use a resistor with an LED. Digital Output explains why.
5. Check your wiring against the lesson before powering up. Most "my code doesn't work" moments are one wire in the wrong row.

warning

Signal pins run at 3.3 V and can supply only a few milliamps — enough for LEDs and signals, not for motors or bright lamps. Parts that need more, like the servo, get their power from the 5V pin, and that lesson shows how.

The lessons

Work through them in order — each one builds on the last:

• Digital Output — control your first LED, understand current-limiting resistors
• Digital Input — buttons and pull-up resistors — the kit's 27 kΩ resistors first, then the chip's built-in ones — plus events and a multi-button reaction-time game
• Breathing LED — control power level with pulse-width modulation
• RGB LEDs — mix colors, first with digital outputs, then with PWM for any color
• Sound — frequency, pitch, and a melody on a piezo buzzer
• Servo Motor — positioning with pulses
• Analog Input — the potentiometer as a dimmer; watch the ADC live in the debugger
• Light and Logic — a photoresistor night-light with hysteresis
• Joystick — a fun project: steer the servo or mix RGB colors with your thumb
• Distance Sensor — measure distance with ultrasound, and see why a radar is just a distance sensor that moves

These three are still in progress — the code and wiring are written, but they haven't been photographed or verified on hardware yet:

• Displays — add a small I²C OLED: text, shapes, a live readout, and a scrolling graph
• FEZ Bit Screen — the same readout in color on the FEZ Bit's built-in display, with nothing to wire
• Addressable LEDs — WS2812 / NeoPixel strips: color, brightness, and animation from C#

The last three need a part beyond the kit, except FEZ Bit Screen, which uses the display already on the board — each lesson lists exactly what to get. More lessons are on the way.

Every lesson has a wiring photo, a schematic, and copy-paste C# code. And because your board runs with the debugger attached, breakpoints and variable inspection work everywhere — lessons point out the spots worth a look.

After the lessons

Everything in this lab uses standard breadboard parts, so the skills carry over to any module you can buy. Free follow-on guides are on the way:

• LED matrices — scrolling text, simple graphics, and your first animation loop
• Common sensors — temperature, humidity, pressure, and accelerometers

Before building your own project, skim Limitations — a short list of full-.NET features TinyCLR trims to fit on a microcontroller. None of them come up in the lessons.