# Seismograph Lesson Build a seismograph with household materials ## Topic Acceleration & Analog Read Pin ## Quick Links * [activity](/lessons/seismograph/activity) * [challenge](/lessons/seismograph/challenges) ## Prior learning/place of lesson in scheme of work Learn how to **show LEDs** to turn on a LED light pattern on the LED screen. We will be learning basic comments such as show LEDs and pause. ## Documentation ```cards basic.forever(() => { }); led.plotBarGraph(input.acceleration(Dimension.Strength) - 1023, 0); led.plotBarGraph(pins.analogReadPin(AnalogPin.P0), 0); ``` ## Objectives * learn how to repeat code forever in the background * learn how to display a vertical bar graph based on the value. * learn how to return the sum of the two numbers * learn how to get acceleration value in milli-gravitys * learn how to read the connector value as analog as a value comprised between 0 and 1023