PRP 7 — Automatic watering

Soil moisture in, pump out, through a motor driver. The pump's power comes from its own supply, not the boa...

6 parts · 16 wires

PRP 5 and 6 — Threshold and hysteresis

The LDR divider from PRP 3, plus an LED the board switches on its own. PRP 5 and PRP 6 use exactly this har...

6 parts · 7 wires

PRP 4 — Temperature and humidity (DHT22 / RHT03)

A DHT22 on a single data line, with the pull-up resistor its datasheet requires. The sensor does its own co...

3 parts · 5 wires

PRP 2 — Current limiting an LED

An LED with a series resistor. The resistor is what makes it a circuit — without it the LED draws as much c...

4 parts · 4 wires

PRP 1 — Voltage divider

Two resistors in series across the 5V rail. The junction between them sits at a fraction of the supply set ...

5 parts · 6 wires

PRP 3 — Light sensing with an LDR

A recorded build: an LDR and a fixed resistor form a voltage divider, and the junction goes to A0 so the bo...

4 parts · 5 wires

PRP 3 · Step 5 — Read the divider on A0

The finished circuit: the junction between the LDR and the resistor goes to A0, so the board reads a voltag...

4 parts · 5 wires

PRP 3 · Step 4 — Add the fixed resistor

The 10k resistor continues from the measurement node down to the blue rail, completing the divider.

4 parts · 4 wires

PRP 3 · Step 3 — Add the LDR

The LDR plugs into the board and takes 5V from the red rail. Its far leg is the measurement node.

3 parts · 3 wires

PRP 3 · Step 2 — Power the rails

5V to the red rail, GND to the blue rail. Everything else feeds off the rails from here.

2 parts · 2 wires

PRP 3 · Step 1 — Uno and breadboard

The starting point: an Uno above, a half-size breadboard below, nothing wired yet.

2 parts · 0 wires

PRP 3 — Light sensing with an LDR

An LDR and a fixed resistor form a voltage divider. The junction goes to A0, so the board reads a voltage t...

4 parts · 7 wires

test

2 parts · 1 wire