The cloud of sensors for the IOT

Deciding on what sensors to create

Going back to the my previous blog post about creating the senses and brains first in my IOT house I decided to do a bit of planning..

I spent a bit of time working through the house, room by room, thinking what could be easily monitored and controlled.

I then put this down in a matrix of sensors that correspond to our five senses, this will make it easier to understand the number of ‘thing’s i needed to get hold of and what is going where and why.

I’ve chosen DHT11’s and DHT22’s because they were the first sensors I purchased (they’re very cheap..) even though I’ve actually found they are quite a poor in both time to get a temperature and humidity reading as well as general usability – but I’ve got them so I’ll use them.

As you can see I’ve only really completed the loft and under-stairs cupboard sensors.  There’s a couple of reasons for this, first is that I wanted to monitor the electricity usage and solar generation ASAP to allow me to understand the spend and usage patterns and these sensors look at the meters.
See for the output from these sensors.
The second is I’m trying to create a boiler-plate code base that I can use for every sensor.  I keep adding adding code for various sensors (PIR’s etc) as and when I’ve fully tested it.

The orange ones are partly complete, they’ve a few sensors on the nodemcu’s and are sending data back to the central brain, these are the ones I’ll be adding extra senors to.

Over time I’ve also started to add more and more MQTT routines as I come across issues.

Each sensor now sends & receives lots of information via MQTT  – standard commands/status topics means I can programmatically work with them using scripts/rules etc from within openhab or node-red.

I’ll be changing* the sensor list as I become more knowledgeable on the whole IOT playground.


*(adding to it…)

Node ID Type (read/control) Placement Description DHT22 DHT11 MQ2 (Smoke) MQ7 – C0 gas PIR Sound Light detection Meter reading(pulse) TCR5000 Rain Relay ds18b20 Light Level (lux) Air pressure RFID reader Doorbell switch Chain Acutator Linear Acutator Light control Realy Weight Dust sensor Sharp GP2Y10
1 Read/control Bedroom 1 Control – Fan control, DS18b20 for air temp, maybe power monitor too? 1 1 1 1 1 1 1
2 Read Bedroom 2 1 1 1 1 1
3 Read Top landing 1 1 1 1 1
4 Read Loft Outside light level (lux), smoke detection, meter reading, temp/humi, 1 1 1 1 1
5 Read Under stairs cupboard 1 1 1
6 Read Front living room 1 1 1 1 1 1 1
7 Read Rear Living room 1 1 1 1 1
8 Read Kitchen Weight for dog bowl, 1 1 1 1 1 1
9 Read Conservatory RFID – cat flap, 1 1 1 1 1 1
10 Read Utility room Boiler control: 1 x relay for boiler, 1 ds18b20 for flow pipe, 1 for return, 1 x dht11 for general temp, mq7 for C0 gas from boiler, MQ2 for smoke alarm, PIR for movement(?) 1 1 1 1 1 1
11 Read Porch Outside ds18b20 for temp, 1 1 1 1 1 1
12 Read Shed (back) 1 1 1 1 1 1 1 1
13 Read/Control Shed (front) Control – velux window, connected to Humidity probe and rain sensor 1 1 1 1 1
14 Read/Control Bathroom Temp/Humi, heater control, fan control – 2x relays 1 1 1 2

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