Who here builds their own sensors (CHAT)


(Aaron) #1

Just wondering who builds there own sensors what platform do you build on ect

At the moment I’m just interested by this

Main questions

  1. what platform do you build from pi, arduino ect
  2. what protocol are you using mqtt, ect
  3. is it cost efficient to build you own
  4. how much coding exp is needed I have none :frowning: ready too try and learn
  5. what sensors are you using temp motion ect
  6. can you send pictures of your finished sensors

(Vincent Regaud) #2

I use these:

Door sensor
image

Temp and Hum

The sensors work with arduino and 2.4gz radios.
They report to a master which forward the messages on mqtt
I haven’t had to change the batteries for more than a year now going on two years for the doors sensors
The system is very reliable


(Aaron) #3

How big are they the door sensor looks huge?

I like your temp/humidity sensor would be nice with a tiny lcd screen that gave current readouts but would prob require wired power


(Vincent Regaud) #4

Only because I put 2AA batteries in them. My next version will use button cells as the power usage is very very low. I don’t open and close my windows all the time.
My temp and hum sensors report to base every 5 minutes and have been going on for more than a year on 2 AAs and are still at 85% battery!

There is a great user base and lots of examples.
You can also buy ready made PCBs and all the software is free and open sourced


(Aaron) #5

I think I need a cheaper solution than zwave for door sensors they are pricey £40+ and windows and doors soon add up


(Vincent Regaud) #6

Same here, I can’t afford ZWave, so I made my own.
By the way it’s also a mesh network, so main powered nodes can relay to base.
My next project is this one:

There is also a binding on the market place but It breaks my existing mqtt for some reason So I continued using MQTT and Node-Red to translate the topics in something more human readable.


(Aaron) #7

There’s just no point in spending that much on door sensors they pretty simple hue motion sensors are £35 and they have 3 sensors I don’t know how they can charge that much for a simple magnet switch tbh

How’s your WiFi network doing how many devices are connected mines shakey already

How much would you say your temp sensors costed in time and money?


(Vincent Regaud) #8

It’s not using wifi so no issues. As I said it’s very reliable.
Some of the radios can be faulty especially the cheap chinese ones so always test them with a breadboard node before soldrering them in.


(Aaron) #9

So how are they connected together?

You said 2.4ghz radio isn’t that wifi?


(Vincent Regaud) #10

They can use different kinds of radios.


(Aaron) #11

That’s something I’m going have too learn

Last time I soldered was in school :frowning:


(Vincent Regaud) #12

Start with a couple or arduino unos and a couple of radios.
You’ll also need an ethernet board for one of the unos that will be your master
and a couple of breadboards, some jumper wires and a few sensors
You can probably start experimenting for about £25 altogether
Then your master uno will stay, your node uno you can use for testing code and radios
And get on with building your nodes

The tutorials are very good, I followed them set by step and Never had a problem except the faulty radios.


(Aaron) #13

Sounds good

It all sounds good tbh do you know what others here are doing are they buying shop sensors or building there own?

Openhab is very hands on lol


(Vincent Regaud) #14

No, I know some other have built their own. A lot use sonoff. I do too but only for actuators and they use wifi so I needed to extend my network.


(Vincent Regaud) #15

I can be, that’s up to you. If you like to tinker, you are in the rights place with mysensors!


(Aaron) #16

I see them as too good too be true they are extremely cheap compared too other smart sockets like wemo, tp link,

It worries me trusting cheap Chinese with electricity that’s constantly on


(Aaron) #17

I love it I have just always done it with computers

Openhab has made me jump into code for rules ect made me try Linux on the RPI and now thinking about building my own devices

Openhab is the best project I have ever started


(Vincent Regaud) #18

I am glad you think so, but be careful and don’t bite more than you can chew. One step at a time and when you mastered on aspect and you feel you are ready for the next project then go ahead.


(Aaron) #19

I agree but having a test of building own sensors is no great loss for £25 even if it goes in the bin and i could learn some new skills

even if Its a loss and can’t get it working there will be lessons learned I’m always up for that

But I do have alot of stuff going on
I can’t code or solder or use Linux (my setup runs on RPI since yesterday working fine)

I’m also backing up my OH so no worries there


(Crispin) #20

I design and build many sensors of my own. Depending on what I “suddenly” need to monitor I will first scour AliExpress or BangGood and if there is not something already rolled, I will build my own.

So far:

-Boiler monitor
Using WeMos, custom Arduino code, a number of DS18B20 and a water flow meter I monitor the cold inlet temp, hot water outlet, heating return and heating flow temps as well as cold-water flow. Using MQTT that reports back which OH2 picks up and graphs.
No pics of the board and sensors but here is the result:

Solar Controller - Shed
Using a number of hall-effect current sensors (ACS712 and ACS758) along with a Wemos , a number of relays, a ADC (ADS1115) I measure the PV panel output voltage and current, the battery voltage and charge current as well as the drain current (gives me a net current).


It can also control the inverter, dummy loads and switch over from street supply and batteries when conditions are right.
It’s further connected into the rest of the smart home and activates a “low power mode” when no one is home and running off batteries.

Bathrooms
Same flow meters and temp meters on all the plumbing in the bathrooms to monitor and log that.

Solar Panels
I have a 2KW set of panels on the house. I want to now measure the voltage (Vmax 500V :D) and the current they put out. From those, and with logging, I can predict better when to run different appliances and how to manage the battery charging to try and ensure they get charge priority over the rest of the house.

Future
I’ve got more ideas than I have time to do. Some practical ones are:
Gas Metering
House electrical circuit metering

For fun - lighting detector using a basic AM radio. When the forecast is for a storm and the detector detects a strike it will flicker all the hue lamps. :smiley: :smiley: It’ll drive my wife mad :slight_smile:

I’ve always enjoyed building my own sensors and measuring everything but never had a single point to use and display it. OH has helped, nay, fueled my addiction :stuck_out_tongue: