
Build your own IoT/MQTT node for less than $2 - albert007_d
http://albert-david.blogspot.com/2018/12/build-your-own-iotmqtt-node-for-less.html
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benj111
For those new to this, you can get little esp8266 based modules with usb,
header pins etc for about the same price.
[https://en.m.wikipedia.org/wiki/NodeMCU](https://en.m.wikipedia.org/wiki/NodeMCU)

Arduino software compatible too.

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rzzzt
Those are really cool. Here's an esp8266 framework primarily intended for home
automation:
[https://github.com/xoseperez/espurna](https://github.com/xoseperez/espurna)

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StavrosK
I use this in about ten devices (one of which is a custom-built dog feeder)
and love it. I hate using closed-source IoT devices and this is a perfect
alternative.

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neeleshs
Please do tell more! Is there a blog?

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StavrosK
My site is at [https://www.stavros.io/](https://www.stavros.io/) and various
smaller projects at
[https://www.makerfol.io/stavros/](https://www.makerfol.io/stavros/). The
particular dog feeder is mostly my dad's build, I only provided the software
and relays to trigger it, so it's not written up anywhere. I can post some
photos if you like.

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Z1515M8147
It's cheap but what's the 0power consumption? This tutorial from Eric Tsai
covers a similar architecture but a lot more extensible, with a lot more
explanation, and each end node can be powered from a coin cell for many years:

[https://www.hackster.io/erictsai/lora-tooth-small-ble-
sensor...](https://www.hackster.io/erictsai/lora-tooth-small-ble-sensors-over-
wifi-lora-gateways-0aa109)

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albert007_d
ESP-12f module running with tasmota firmware consumes around 30mA when
measured on the 5V side, if you want to go further down, deep-sleep option of
ESP8266 is the way to go, but tasmota firmware doesnt support deep-sleep(may
be you need node-mcu firmware to achieve sub-mA consumption). There are CR-123
3v battery powered ESP8266 temperature/humidity products which use deep-sleep
mode and report the sensor samples every hour so that devices operates atleast
a year on battery power(check out shelly H&T product)

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NicoJuicy
I recently found out about Sonoff-Tasmota (
[https://github.com/arendst/Sonoff-Tasmota](https://github.com/arendst/Sonoff-
Tasmota) ), i hate it. Because now i bought for 300 € of Sonoff products for
home-automation based on the MQTT protocol.

(The project allows you to flash the Sonoff products with custom firmware)

They also have an IR module, for customizing your remote.

Anyone else has other ideas that are similar for home automation without
adjusting your electronic wiring?

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whitlock
Like you hinted, flashing Sonoff-Tasmota firmware on ESP8266 hardware lets you
get A LOT of home automation equipment for fairly little. They make many
devices and someone getting started should checkout the Sonoff-Tasmota for
supported devices AND check out Sonoff.

If you don't want to use a Sonoff Basic or maybe the bigger 4 channel option,
I'd suggest getting some of their wall adapters like the S31 (think Wemo wall
plug). There is a confirmed flash for Sonoff-Tasmota & ESPurna for it and
would let someone dip their toes into cheap home automation with MQTT.

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diafygi
Is there an hobby equivalent for Bluetooth Low Energy (BLE)? Wifi tends to be
power hungry for battery-operated devices. With BLE, you can get months of
lifespan while still being able to connect to it with your phone.

I was looking at the micro:bit, but it's still $15. Anything in the $2 range
for BLE?

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StavrosK
Try the ESP32, it might fit the bill, although I've never worked with its
Bluetooth capabilities and don't know much about them.

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wybiral
I've experimented with those ESP32 chips from a few sources on a handful of
boards (lots of cheapo knockoffs floating around) and haven't been happy with
the performance or reliability of any of them for BLE. So far Nordic nRF52
holds the lead in my experience (they do cost a bit more though).

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jsjohnst
Nordic is good, but STM32 is also affordable and quite decent.

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samstave
Can someone ELI5 what can be accomplished with these devices?

I am not familiar with them, and the build looks simple - but what do once
created? Is it simply a BLE beacon?

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blackfawn
The ESP8266 is wifi. The slightly more expensive ESP32 adds Bluetooth and some
extra features. You can use them to run mini web server, MQTT, etc. Think of
them like a supercharged Arduino with connectivity built in.

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samstave
Ahh - so coupled with whatever sensor you have, you can have a wifi broadcast
capability at extreme low cost...

So, ostensibly - if you have these all participate in an SSID of e.g.
"sensors", then you can place these all over and have a low-cost mechanism to
deliver the reads to your (already) existing wifi infra...

So the key, then, is the family of sensor types you want to place on them. The
limitations in the case of this object are power and size....

So given that - whats the minimum size battery req'd to run this little guy?

Then What is the power req of the sensors you attach -- then whats the
lifespan of that power budget and then servicability to replace it?

I like this... a lot.

I have a bunch of BLE sensor beacons from china which cost ~8 but they are
dumb as rocks.

This provides a heck of a lot more functionality than those...

Unless there are gotcha's which I am naive to?

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general8bitso
Battery depends more on what you are doing.

Most boards and sensors use either 5 or 3.3 volts DC.

You can put the device in a sleep or hibernate mode and have it only connect
to wifi periodically or when triggered.

Also, using encryption, like WPA2 increases battery use.

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beardyw
The esp8266 module itself runs at 3.3V but seems happy with a couple of AA
batteries. Tried with CR3032 but it can't deliver enough current. After all,
it is doing WiFi.

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general8bitso
Google ‘joule thief’.

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drudru11
This is interesting. What chip do ESP12F's have for USB?

I did a quick search and nothing came up. Most ESP8266 projects refer to the
node mcu board rather than the module. Those boards usually have a USB <->
serial chip.

