Hello Blocks
Show a greeting in the output panel.
Output
Lesson Catalog
Explore programming and electronics lessons. Progress at your own pace — no account required.
Ordered Instructions
Print first, then second, in order.
Sequence
Recommended prerequisites:
- Hello BlocksRecommended before this lesson
Repeat a Pattern
Repeat a greeting three times.
Loops
Recommended prerequisites:
- Ordered InstructionsRecommended before this lesson
Make a Choice
Use an if-else condition to choose between two outputs.
Conditions
Recommended prerequisites:
- Ordered InstructionsRecommended before this lesson
Remember a Value
Store a number in a variable and print it.
Variables
Recommended prerequisites:
- Ordered InstructionsRecommended before this lesson
Reusable Instructions
Define a reusable function and call it with different inputs.
Functions
Recommended prerequisites:
- Repeat a PatternRecommended before this lesson
Blink an LED
Observe three LED on/off cycles with a one-second wait in each state.
Timing
Recommended prerequisites:
- Repeat a PatternRecommended before this lesson
Control a Button
Turn the simulated LED on when the simulated button is pressed, and off when released.
Simulated Input
Recommended prerequisites:
- Make a ChoiceRecommended before this lesson
- Blink an LEDRecommended before this lesson
Make a Buzzer Sound
Activate the simulated buzzer for one second, then silence it.
Device State
Recommended prerequisites:
- Blink an LEDRecommended before this lesson
Automatic Street Light
In a Kigali street-light teaching model, turn the LED ON below 30% brightness; OFF at 30% and above. Brightness is normalized 0–100%, not lux.
Simulated InputConditionsDevice State
Recommended prerequisites:
- Control a ButtonRecommended before this lesson
Temperature Alert
In a Rwandan classroom teaching model, activate the buzzer indicator above 30°C; OFF at 30°C and below. Simulated temperature range: -40 to 125°C.
Simulated InputConditionsDevice State
Recommended prerequisites:
- Make a ChoiceRecommended before this lesson
- Make a Buzzer SoundRecommended before this lesson
Water Tank Indicator
In a Rwandan school water-tank teaching model, turn the low-level LED ON below 20% fullness; OFF at 20% and above. Fullness is normalized 0–100%, not litres.
Simulated InputConditionsDevice State
Recommended prerequisites:
- Control a ButtonRecommended before this lesson
Traffic Lights
Run at least two cycles: red LED 1 for at least 2 seconds → green LED 2 for at least 2 seconds → yellow LED 3 for at least 1 second. Only one light may be ON, including between waits.
SequenceTimingDevice State
Recommended prerequisites:
- Blink an LEDRecommended before this lesson
Smart Irrigation
In a Rwandan garden teaching model, LED 1 indicates irrigation demand only when reservoir fullness is at least 20% AND temperature is above 30°C. Otherwise OFF. This LED is not a pump.
ConditionsSimulated InputDevice State
Recommended prerequisites:
- Water Tank IndicatorRecommended before this lesson
- Temperature AlertRecommended before this lesson
Build Your Own Mini Project
Choose one bounded project: Blink (three ON/OFF cycles, 1 second each), Street Light (LED ON below 30%, OFF at/above), or Irrigation Indicator (reservoir ≥20% AND temperature >30°C). Complete its observed rubric; other inventions are practice only.
ConditionsSimulated InputDevice State
Recommended prerequisites:
- Traffic LightsRecommended before this lesson
- Smart IrrigationRecommended before this lesson