2 Double Side Prototype PCB Board 3x7cm

Led IR 3mm is a pair of infrared LED's consisting of a photodiode (Emitter) that emits an infrared light when polarised through its working voltage ranges and a phototransistor (Receiver) that allows to capture the infrared light emitted by the photodiode.

Resistors 2K Ohm 5% 0,25W 1/4W features:
-2 Ohm
-Type: Carbon film
-Tolerance: ±5%
-Power: 0.25W
-Dimensions: 2x7mm

This support is a lilypad button to sew clothing or anything else you can dream of.
Lilypad is a wearable E-textile technology developed to have large connection pads to attach to clothing. Lilypad Button Board features:
- Density of the PCB: 0.8 mm
- Size: 8x16 mm
- 1 LED included

Arduino Shield Sensor Expansion Board V2.0 features:
The Mega Sensor Shield V2.0 allows: - To be directly punched to an Arduino Uno, Mega, Leonardo board
- Facilitate the connection of different modules, such as sensors, relays, servos, buttons, potentiometers and more
- Size: 100x54x12 mm

High sensitivity to Ammonia (NH3), Nitrogen oxides (NOx), Alcohol, Sulphides, Benzene (C6H6), CO2, smoke and other harmful gases.  The MQ-135 sensor is to sensible for other gasses in the air so that is not possible to get good values for CO2 from it.
MQ-135 Air Quality Sensor features:
- Main chip: MQ-135 natural gas sensor and comparator LM393
- Working voltage: 5V
- Current: 150mA
- Digital output: TTL 0/1
- Analog output: analog voltage sensing value
- Quick response features:
- Detection concentration:
   10ppm - 300ppm NH3
   10ppm - 1000ppm Benzene
   10ppm - 300ppm Alcohol
- Adjustable sensitivity with the potentiometer
- Size: 32mm x 20mmx 18mm

Descent module.
Use a multimeter to check the output voltage and adjust the potentiometer.
Control of tension.
LM2596 DC Voltmeter Converter 3A Step Down Adjustable Power features:
- Input voltage: 4.5-38V
- Output voltage: 1.25-36.5V
- Current output: 2A (max 3A with heat sink)
- Operating temperature: -40 to + 85 ºC
- Operating frequency: 150KHz
- Efficiency conversion: up to 92%
- Load Regulation: +/- 0.5%
- Voltage Regulation: +/- 2.5%
- Protection over temperature: the output switches off automatically
- Size: 62mm x 38mm x 15mm
Principal functions:
- Step-down converter with overcurrent protection
- Voltmeter up to 40V, remember to set the input voltage to 4.5V

Characteristic:
-Metric thread M3
-Male-Female separator 25mm
-Quantity: 5 units