If so - hi, I’m new to the forum and the technology!
I would like to know if Home Assistant is an alternative to Samsung Smarthings or Lightwave RF Hub ?
So : if I configure a Raspberry Pi with Home Assistant, is it the same as having a Samsung Smartthings hub?
I wish to buy an inline relay in the style of Lightwave RF, Fibaro or Sonoff to control different lights outside, and I also want to add some IP cameras to the system, do you think Home Assistant is a good option for that?
This forum is a great place to start 
In answer to your questions - hubs like Smart Things and Wink etc. do 2 jobs:
A Pi on it’s own would be just number 2, but you can buy USB Sticks to add Zwave and Zigbee, and PIs come with Bluetooth and of course WiFi. When you put that together, a Pi with the appropriate hardware can do what ST can do, but importantly does it all locally whereas ST and Wink rely on the cloud which is a huge downside for home automation IMO.
Just to make it more confusing, you can use ST and Wink just as number 2, connected to Home Assistant so you can benefit from their radios but not use the rest. This may be a good way to start if you already have one of those devices but is not optimal as you are introducing cloud dependencies back in at that point.
Home Assistant would be an excellent choice for that - here is a list of what it supports (over 700 technologies at the last count)
thanks for a really helpful reply aimc!
Can I just clarify, that for 1 + 2 (going down the Pi route), to add 1 I would need to buy a USB stick which is a Zwave or Zigbee radio?
EDIT: Another quick clarification: I Don’t see Sonoff in the list of supported tech, does that mean it doesn’t work?
Well it kind of depends on the route you want to go down, cost/versatility/ease of use + few others I can’t think of right now, fibaro is zwave (expensive - but well used and fairly reliable- i use it for the odd sensor I managed to get cheap, but you need a dongle), xiomi (sp) is zigbee ( i think - is cheap, not sure how reliable others can answer that), lightwave is rf (433mhz i think - so would need a separate 433 mhz hub/device - I use various makes of chinese rf radios, + when I can get it going the RFLink)), sonoff is wireless so would need no extra HW, but to get the best out of it will need hacking/reprogramming. In theroy BlueTooth is supported by the PI3 (for sensors/device tracking) but I find a dongle works better (for now at least). So I agree with @aimc a PI is the way to go (it’s what I use since it’s always on and I don’t want my PC on all the time), however depending on how willing you are to play with stuff and use a soldering iron, configure SW/HW a PI maynot be the best way to go 
Pretty much yes - but only if you need or want to use ZWave devices or ZZigbee devices. As @keithh666 says - there are quite a few choices of device ecosystems out there that will dictate what you need in addition to the pi.
I use Zwave for motion detectors, light sensors etc so I have the stick. I use Hue for my lights which doesn’t need anything extra.
here are some random musings
CON: As much as I don’t wish to - I’m trying to get out of the DIY game, but still need to do stuff on the cheap
CON: I get a 30% discount from all Samsung things, so it would make the smartthings hub and their sensors quite cheap.
PRO I want to use an inline relay and can’t see an easy or cheap way of doing it with Samsung Smartthings, because Sonoff seems to be by far the cheapest way of doing that. It looks like I can do it in home assistant but with some fairly significant work involved
PRO It looks like most IP cameras will work with Home Assistant so I could buy a nice Hikvision, but Smartthings only accepts a few branded expensive cameras like Netgear Arlo
For the Sonoff, it depends on what you mean by significant work, you will need to either solder a header into the sonoff or have very stable hands and you will need a bit of knowledge to get the arduino code uploaded and configured, but once you’ve done it , it very quickly becomes 2nd nature well almost 
As for cheap well depends on what you mean by cheap, from what I can gather Smartthings are £30/sensor + a hub for you £21/sensor given that for my studio flat that would be around £315 just for the door/window and PIR sensors, without any switching capability or IR/camera/water/heating temp/humidity/dust/co2 sensors etc, Zigbee is a bit cheaper I think, 433mhz is dirt cheap but you won’t get any feedback and that can be important. So a bit to think about Thing is once you get the bug you will want to monitor everything and that can be very expensive.
Just to add one more thing. If you want to get your feet wet with Home Assistant without investing any money and don’t mind leaving a computer on, there are a bunch of things you can try that don’t require hardware. You can install it on whatever computer you have now and try not to get sucked in like the rest of us 
.
Ex. Tracking your location based on your cell phone, and send a message to someone else that you made it to work…
As @keithh666 said, once you start it’s easy to go a bit nuts with it. I know I did.
On the point of the sonoff then… Could you point me in the direction of some links I can see about this soldering please? Soldering Is fine and I’d love more than anyyhing to write scripts for arduinos but this is what I wanted to avoid by buying an off the shelf consumer grade item
about cost this is what I had in mind
Samsung
Samsung smart things hub £70
3 x door sensors £100
Can’t do inline relay as far as I can see so £0
Home assistant
Hub £0 I’ve loads of pis
Zwave USB £50
Sonoff £30
Door sensors £50
How far off am I, these are total guesses except the Samsung hub which I’m certain of
If you have the ZWave stick why the ST hub - it introduces cloud dependencies.
Huge Sonoff thread in this forum, see a few posts above also google sonoff hack etc. It’s not hard just need a pin header, solder and soldering iron, some connecting wire and a ftdi connector, once the new firmware is flashed you can OTA update via wifi.
I can’t speak to ST as I’ve not used.
As for HA I’m not sure why only 3 door sensors and why they would be cheaper in HA, they will prolly still be ZW and therefore approx. £30+ ea. All my doors have sensors on but I only have 4 doors (studio flat - also I went for 433mhz which is much cheaper). Sonoff see here https://www.aliexpress.com/item/2pcs-New-Sonoff-Smart-Home-Wireless-Remote-Control-Wifi-Switch-Intelligent-Timer-Switch-Diy-Switch-220V/32766063186.html £24 for 5, they do various types more or less current etc.
@aimc I think it’s an or between the two options, ST or HA, tho’ what you say is true ST is cloud based and therefore break in the internet or router goes down you can’t control anything 
I think he may have meant either or with the Samsung/Homeassistant prices. Ah @keithh666 already caught that, nm then
Why not go with Xiaomi Door Sensors - around $6-$10 each plus approx. $23-$28 for the gateway… I have a few and they seem to be reliable…
And if you have the gateway you can easily integrate the Motion Sensor, Temp/Humidity Sensor and wireless switches (plus more to come).
TBH I just literally made those prices up, they were pure estimates. I’ve seen stuff like the wirelesstag.net stuff before and I thin they were more money.
I like Xiaomi stuff and I’m glad you mentioned those, they’re an absolute no brainer at that price, i’ll be doing every door in the house 
do you have to buy the gateway and link that to Home-assistant? meaning you can’t just link the xiaomi door sensors straight to home assistant directly?
Interested to hear your experiences of them.
The best source with looooooots and lots of information is the Xiaomi thread here in this forum:
It’s not a beta stadium anymore, it’s an official component since 0.5x
Right now I don’t have a lot of time to work on the HA stuff But I already have the gateway and a couple of sensors installed. The Temp- / Humidity sensor seems to be quite stable and reporting correctly. Same for the Door- / Window Sensor. I have one Motion Sensor installed (in the office) and it seems to be working as well - but I read about some “ghost readings” in the Xiaomi Thread… Last but not least I’ve connected one of the Smart Buttons and got it working with HA (automations) as well.
And YES, you need to have the gateway. There are infos on the internet that people got if working with other Zigbee hubs but I have no experience with it. For me the gateway is perfect, because it plays my doorbell tone when someone hits the Ring doorbell - so I didn’t had to buy the Ring Chime
As you see, endless options 
Xiaomi has Gas- and Smoke Detectors and several other switches as well. Definitely something to look into deeper!!
Last tip (for now). You can buy from Gearbest and check out the “Buy together” option. For example, if you buy a Temperature Sensor, you can get Motion Sensors, Buttons or Window- / Door Sensor for less.
$11.11 Temperature Sensor
$ 8.78 Door and Window Sensor
$10.48 Motion Sensor
$ 6.88 Smart Wireless Switch
$28.99 Gateway
$66.24 all together when you buy it one by one
$11.11 Temperature Sensor
$ 6.86 Door and Window Sensor
$ 8.79 Motion Sensor
$ 5.47 Smart Wireless Switch
$24.88 Gateway
$57.22 if you buy it as a “bundle” - which is 15% less
Check out AliExpress, DX, Gearbest and Banggood - every store has it “Flash Sales” where you get stuff for cheap(er).
If you have any more questions, don’t hesitate to ask!!
Bye,
Daniel
That’s a really helpful post, thanks
Can I assume you connect the Xiaomi gateway to your home assistant via ZigBee? So I’d need a ZigBee usb stick for my pi.
I really like the sounds of all the cheap xiaomi sensors and switches 
time to get buying.
Btw how bizarre is it that Xiaomi gateway can use ring stuff?! I didn’t know that till you posted. I’ve a ring video doorbell and love it. I also have a Chime but maybe I could use both
The gateway connects to your router via wifi and connects to your switches/sensors etc via zigbee
Right, like keith666 already wrote, the Xiaomi Gateway connects to your local WiFi and Home Assistant then has an IP connection to the gateway. The gateway itself connects via ZigBee to the different sensors.
And yes, the sensor are cheap for sure. Like I wrote before, each store has a sale going on all the time and you normally get those sensors for under $10. Xiaomi released a Water / Leak-Sensor a couple of weeks ago, which is on sale for around $15-$16 at the moment - but it is not YET supported by the HA component. But it’s just a matter of time
The gateway also has a LED ring light, that can be used (for example) as a night light. And around 10-12 sounds as default (doorbell, dog bark, bomb siren, …) which you can play via an automation (that’s what I did for the Ring doorbell). Or you can upload MP3’s (??) by yourself and use those as a ringtone or alarm siren. You can for sure use both - especially if your house / condo is spread out
Order now and while you wait for the delivery (approx. 1-3 weeks) just read the Xiaomi thread I linked in my other post and you’ll see how easy it is to get it up and running. And if you still have questions or problems, this community here is always willing to help
Always keep in mind: There is no stupid question (ok, NEARLY no stupid question), only stupid answers… I wish I had more time right now to install and set up all my stuff I have sitting in my office
just FYI - these few lines of code (automation) are all you need to play a ringtone when someone hits the button at your Ring doorbell
- alias: Play Doorbell
trigger:
platform: state
entity_id: binary_sensor.ring_front_door_ding
to: 'on'
action:
service: xiaomi.play_ringtone
data_template:
ringtone_id: 10
ringtone_vol: 75
gw_sid: !secret xiaomi_sid