This is a list of all the parts I have bought so far, including affiliate links to where I bought the parts and links to relevant posts about them. For my records, as much as anything. Unless I have commented negatively you can assume that the parts arrived within a reasonable time frame (for example I would expect items being posted from China to take a lot longer) and worked for me (I will add a note if I haven’t tested it yet). Of course this does not necessarily mean these are the best places to buy things from, it’s just where I happened to buy them from, so use your own judgement.

Note: The prices shown are the prices I paid and may not be the current price.

Item Purchased from Cost Notes Blog post Datasheet
ESP8266 Serial Wifi Wireless Transceiver Module Ebay £3.19  Flashing ESP8266  Adafruit
2 x NRF24L01+ Wireless Module 2.4G Communication Module Amazon £1.70  Untested Sparkfun
[Initial purchase] RF transmitter and receiver kit Amazon £1.08
RF transmitter and receiver kit Ebay £1.38
YL – 69 Hygrometer Ebay £2.29
10 x LDR G5528 Photoresistor Ebay £1.18
DHT11 humidity and temperature Ebay £1.48  Testing DHT22 and DHT11
DHT22 humidity and temperature Ebay £2.09  Temperature and Humidity (DHT11 and DHT22) on the Arduino

MQTT Connected NodeMCU Weather Station

Raindrops sensor Ebay £1.99 Untested
4-channel Bi-Directional Logic Level Shifter Converter 3.3V 5V Ebay £1.99 Untested
12V Dosing pump Peristaltic dosing Head Ebay £4.39 Untested
LCD Character display Amazon £1.54 This took a long time to arrive.
PAM8403 5V Digital Audio Stereo Player Amplifier Board Ebay £0.99 Untested
Ranking MB102 Breadboard 3.3V/5V Power Supply Module 3.3V/5V Amazon £1.11 Flashing ESP8266
FTDI FT232RL USB to TTL Serial Converter Adapter Module 5V and 3.3V Ebay £3.29  Flashing ESP8266
DS18b20 Waterproof digital probe thermometer temperature sensor Ebay £2.07
USB Nano V3.0 ATmega328 Ebay  £1.79
2PCS L298N Dual H Bridge Stepper Motor DC L298N Drive Controller Board Ebay  £2.84
2PCS ESP8266 Serial WIFI Wireless Transceiver Module Send Receive LWIP AP+STA Mo Ebay £3.25
IIC I2C Logic Level Converter Bi-Directional Module 5V to 3.3V For Arduino M Ebay  £0.99
USB to ESP8266 Serial Wireless Wifi Module Board Developent 8266 Wifi Module M Ebay  £1.25
2PCS IR Pyroelectric Infrared IR PIR Motion Sensor Detector Module HC-SR501 M  Ebay  £1.41 Datasheet
HY-SRF05 Ultrasonic Distance Sensor Module 5Pin Replace SR04 For Arduino Module  Ebay  £0.99
Digital BH1750FVI Light intensity Sensor Module For AVR Arduino 3V-5V power M Ebay  £0.99 MQTT Connected NodeMCU Weather Station
5V Stepper Motor with Drive Test Module Board NEW ULN2003 Ebay £1.25
MAX7219 dot matrix module Arduino microcontroller module control Display DIY KIT Ebay £1.20
0.56″ 7-Segment 4 Digit Super Red LED Display Common Anode Time 12 pins NEW Ebay £0.99
NodeMcu Lua ESP8266 CH340 WIFI Internet Development Board Module Ebay £2.52 MQTT Connected NodeMCU Weather Station
LDTR – 0011 5mm RGB LED Module Gearbest £0.63
LDTR – B00010 10mm 7 Color Light LED RGB Module Gearbest £1.25
3904 Soil Humidity Sensor Gearbest £0.57
BMP280 BOSCH Atmospheric Pressure Sensor Board Gearbest £2.41