Economic WiFi Home Automation Sensors


(Vladimir Savchenko) #1

Hi Guys,

In the discussion around around here, i got the impression that there is a lack of affordable WiFi-based sensors to plug into existing home automation systems.

With this I mean sensors for temperature + humidity, pressure, IR/UV Light, Dust, CO2, Motion, etc. But also some Wifi Button, Wifi Light, Relay, TFT display

Reading the forum, and browsing some product offerings - i can see that the majority uses XBee, which is low-power but the price tag for some may be a bit high. Or there are end-user-devices that use their own app/protocol also costing a lot. And finally there is the DIY class, where one can buy the modules, assemble and program them, but not everybody is happy with soldering, wires, etc.

I may be wrong of course in my assumption :slight_smile:
But based on it i wonder if you would be interested in a new series of devices i would like to produce. The key design drivers would be: cost, integration, ease of operation.

They will come in a (nice) 3D printed box, will not have a state-of-the art mobile app for configuration. But they will be as cheap as it gets, integrate easily with an existing HA system, or some online data services. Send data over HTTP or MQTT. And configuration will be done over Wifi or USB Cable. Since Wifi uses lots of power, maybe they will not work too much on batteries.

The prices which i target will be around 10 eur for the bare device (only a button and RGB Led), and then 5-6 eur for each additional sensor (45 for co2 and 50 for dust). So a Wifi Temp/Humidity sensor will be no more than 16-18 eur.
I will most probably start it on Indiegogo, to get some scale so that i can match those prices.

I am really keen on making those (Also as part of another project), and I will be very thankful if you could share some feedback on feasibility, pricing, scope, etc

Thanks in advance, Vladimir


(Stuart Buchanan) #2

presumable these will be based on the particle.io prototyping platform?


(Vladimir Savchenko) #3

I have not thought on this yet… but perhaps I could also integrate with particle.io
my idea is to have them more as end user devices which you just configure… of course you vcqn also program them


(sidjohn1) #4

You choice of wifi may cause you issues getting the the price down as wifi requires quite a bit of power. So far battery powered wifi devices have not done well due to this. It won’t be an issue for lights or relays, but for sensors and buttons requiring a power cable will not be welcome.


(Vladimir Savchenko) #5

yeah… I wa also worrying if a temp sensor bound to a cord makes any sense :slightly_smiling:
some people report that the esp8266 modules I will be using may work about an year on two aa batteries and a 5 min update interval. so maybe if I put 2 C cells it will work reasonably well for almost 2 years… maybe I will have to look into this as well


(Jason) #6

I’m not sure what you have available over there, but this equates to about $18-20 US, while I see an market for lower cost devices, Here in the US you can get Packs of Iris sensors for ~$26 consisting of 2 contact/temp, 1 motion/temp, 1 button, 1 plug Or Less if you follow the Deals Thread. These connect to ST automatically. This is just one example, there are others.


(Vladimir Savchenko) #7

Yeah… this is quite interesting, i did not know about it - thanks. I will have a look on them as well :wink:


(Jason) #8

Also in not sure if monoprice has UK zwave frequency devices , but their us ones are 22-25 use for motion/temp and contact sensors.


(Geko) #9

That’s very unlikely. On two lithium batteries, maybe, but then the battery replacement cost would be too high. Also, WiFi is not a mesh network, like Z-Wave or ZigBee, and considering small antenna, ESP8266 will not work more that 30" from the router, or even less through the walls. Unless, of course, you plan to use external antenna, but then again, it would be more expensive to make.


(Cody Truscott) #10

If you are looking into playing around, you’d be better off with btle modules.


(Vladimir Savchenko) #11

I believe Wifi is not that bad. About the batteries, i still have to verify it myself of course, but in general there is no real capacity difference between lithium and alkaline batteries (no technology breakthrough unfortunately). Both have ~ 2000 mAh, just lithium can spend the energy much faster.
And about the reach, for sure wifi is worse than radios on 900 mhz, but specifically the ESP8266 module is quite powerful (hence - the battery life;) ) so i can confirm that it is working fine ~ 45 foots (14 meters) from my router, through 4 brick walls


(Geko) #12

Ha-ha, buddy, good try, but no, you’re incorrect. AA are 1.5V, so you connect them in series to get 3V, while CR123 batteries are 3V. So, you connect them in parallel to double capacity. :wink:

i can confirm that it is working fine ~ 45 foots (14 meters) from my router, through 4 brick walls

That is a tale worthy of baron Munchausen. :wink:


(Vladimir Savchenko) #13

sorry, maybe i did not express myself correctly.
I meant that lithium and alkaline AA batteries, and not the Lithium CR123. Their only benefit is when used in digital cameras and in fact are indeed quite expensive

For the range - if you do do not have a module at hand to test it, it is hard to judge. But in general i have noticed that it is on par with the wifi reception of my Samsung S4 (even better at times)


#14

The advantage to lithium batteries for low-power applications is their low self-discharge (10 years in many cases), meaning if you create a truly low-power design you can run it for a decade. Other primary cells will drain charge just sitting on the shelf meaning there’s a built-in expiration.

In regards to the thread topic - the hardware part can already be done cheaply and in a plug-and-play manner with an inexpensive microcontroller, a breakout board, and some cheap sensors. There’s no knowledge or soldering or circuit design necessary for people to create their own hardware right now (but it’s even cheaper if you do have those skills).

What we really need is some help with the code! If you’re up to it, a few of us are hacking at some code started up by @Charles_Schwer over in this thread. If you have some skill with this we sure would love a few extra hands hacking at the idea.

The ESP8266 is dirt cheap and super capable, and it’d make a great platform for adding DIY sensors and control to existing things in your home.


(Vladimir Savchenko) #15

Thanks for the reply. I did not knew about the Nodemcu breakout board! i is a great gadget indeed that bridges nicely from nodemcu to the sensors
Regarding the code - i would love to… i am following the thread you mentioned as well. Few days ago i ordered a 2nd-hand hub from ebay, and now i am waiting for it to arrive to start hacking as well. I just hope that i did not make a mistake when buying the v1 (but it was much cheaper than the v2 :slight_smile: )… we will see


(Geko) #16

I’m afraid you have. $99 retail price for V2 is not bad. You can find a used V2 on Amazon for around $85. V1 is very limited and the firmware have not been updated for a long time (and unlikely ever will be.)


#17

Counterpoint - the V1 does almost everything that the V2 hub currently does, outside of battery backup and local execution of the Smart Lighting app and even that comes with a lot of restrictions making it less useful than it could be. Maybe in the future there will be some use of things like the USB ports or the Bluetooth radios, but as of today I think the V1 hub should do basically everything you’d want. It’s certainly enough to start working on development for the ESP8266 or whatever other device you might be toying with.

Grab that v1 and start developing!


(Geko) #18

The recent V2 firmware update was supposed improve LAN device discovery among other changes. We know that V1 had a ton bugs, but it looks like it’s now considered legacy and will gradually slip into oblivion.

The update includes improvements to LAN-based device discovery, Hub connectivity, security, live streaming, and Z-Wave device removal.


(hakem) #19

Wow nice ! We are all on same wavelengt. Z-wave ans zibgee are excessively expensive sensors for a full installation. I turned to loo at BLE , Wi-Fi and ISM sensors and ended up ordering a Dev kit for ESP8266 with exact sâme idea. I think all can work in their context

1-) basic sensors lie door sensor that only sends signal can be used with 433mhz or basic no need to spend 30 usd to get a nice one. I will try to build one with esp8266 and see how it goes

2-) more sophisticated devices justify to spend money on it

I am into the game of sharing after receiving my adafruit esp8266 huzzah kit. We will then experiment. The dream would be to : take any cheap sensor at 4 usd and enable it ( like the roost idea ). That would be just plug and play wireless enable