Archive for the ESP8266 Category

Pegaleg

Posted in ESP8266, MQTT, node-red, OpenSprinklette on November 11, 2018 by asteriondaedalus

So, one file I had fun getting off my laptop was the source for the parser for the google calendar event titles.

The titles, as discussed previously, would be a list of sprinkler group or unit callouts.

I managed to ssh onto the laptop from my desktop to lift anything I wanted before I trashed the laptop with a clean Debian install.

While waiting for the install, I opted to tart up the parser with some sanity.

The problem for the distributed opensprinklette design is that there is no editor per se to police the entries in the google calendar event title. So, if any unwanted text is in the title, the parser running on the node-red server will drop the lot. Harsh I know, but the distributed nature of this entails some trade-offs.

So, I did add some smarts to avoid sending repeated call-outs to a sprinkler. A burst of call-outs will go out once the event title is parsed. The ESP8266 gadgets don’t mind if a single sprinkler is pummelled – it simply results in the time starting from the last received call-out – which won’t be that many milliseconds behind the first.

Still, to opt for a defensive scheme meant testing for a call-out in the return from the scan of the line before adding it to the return. Simples tick!

So, even if the user pummels the title of the event with multiple call-outs to the same sprinkler, the parsed response will only contain a single call-out.

So something like this in the google calendar title:

group1=1;group1=[1];group1=[2,2,2,4,4,4,4,1,1,1,3]

will return the following in the node-red response (prior to fully concatenating into a MQTT topic):
[
"group1/1",
"group1/2",
"group1/4",
"group1/3"
]

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Opensprinklette Single!

Posted in Embedded, ESP8266, Hardware, OpenSprinklette on October 15, 2018 by asteriondaedalus

20181015_172706

So, found some info on the board.

Where I thought there was dual throw relay, it’s even better since the second set of terminals are a optocoupler. So, that would be grand for either of a rain gauge input, the audio trigger for dog barking, the flow rate sensor et cetera.

It is otherwise an WeMOS ESP-8266.

What is crazy is that the board thinks of everything and has bidirectional zeners on power and optical inputs so its really for light-industrial applications. That is, includes Transient Voltage Suppressors.

AND! One of the terminals is a regulated 5V output! Just exactly enough for the sound level detection for the dog barking.

Loving it!

Small steps

Posted in Embedded, ESP8266, IOT, MQTT, node-red, NodeMCU, OpenSprinklette, WEMOS D1 R2 on August 7, 2017 by asteriondaedalus

I have roughed a node-red config node and it’s visible counterpart.  I decided to call wemos nodes “sectors” – since the usual rort is to call a single channel on an irrigation controller, controlling a single solenoid, a zone.

I have set up for 4 sectors each using a WeMOS D1R2 with a quad relay shield.  That provides up to 16 zones (4 per WeMOS).

You need to mod the relay shield with a couple of pullup resisters.  This is to get around a design shortfall on the WeMOD D1R2.

I am using a protoshield in between the WeMOS and the relay shield to allow for fidgeting with design changes. I added a four position dip to set the zone id BUT I dropped that in favour of the config node concept.

That gives me back 4 pins for GPIO. The problem is the out and out lie that the WeMOS is a Uno form factor. The ESP8266 has to cheat by using the same GPIO pins across a couple of Arduino socket pins.

I will add the rain gauge input later.

The idea is an input line such as the following as the title of the google calendar event:

sector1=1,sector3=4,sector2=0,sector3=1

The line above shows you some of the input features I will aim for, being:

  • You don’t need to nominate all four sectors or even all four individual zones of a sector.
  • You can order the sectors in any order.
  • The zones per sector are number 0..4 with 0 being the global all on/off id for all 4 zones on the addressed sector.

I did think about using JSON as input but the problem is that if you have two tokens the same then the object construction takes the later value in the line for the key.  Oh well.

For this to work you attach two google calendar event sniffers, one to flag the start of an event and one to flag the end.  Both feed into the opensprinklette-configurator to decode the events into MQTT calls to the 4 WeMOS D1 R2.

Of note, the configurator maps between chipid() and sector# (and back again) so planning the sprinkling can be in people-talk (relatively speaking).  At least you don’t have to remember which WeMOS chipid() was allocated to what sector.

Of course, there are quirks to do with the distributed system.  There will be a watchdog on the WeMOS to automatically turn off the water to a zone after 45min.  To plan out longer watering you will need back to back calendar events (shorter than 45min to avoid the watchdog).  If that is offensive please send money to help me pay the water bill of a runaway commercial setup ($3,000 in fact).

The other option I guess is send the duration to the WeMOS node and let it do the countdown.

I will play with a couple of timing approaches to see what is most robust – given you could have the ISP gateway drop out, the node-red crash, the emqttd crash, the OPiZ drop of the network.  Not to mention, google calendar hickups – I occasionally get a baulk around credentials lapsing that somehow comes good again.  Oh and of course, the WeMOS could also behave badly.

All in all needs a good bashing to help weed out nuisances.

Back to work

Posted in ESP8266, Lua, MQTT, node-red, OpenSprinklette, Orange Pi, WEMOS D1 R2 on August 5, 2017 by asteriondaedalus

So, at last, now that the OPiZ setup saga is over (fingers crossed) we begin over.

I built a new nodemcu firmware for the WeMOS to include:

  • bit
  • end user setup
  • file
  • GPIO
  • MQTT
  • net
  • node
  • RTC Time
  • SNTP
  • timer
  • UART
  • Wifi

A few coding snippets later and  the WeMOS can catch the mqtt topic running on the OPiZ feed by the node-red on the OPiZ.

wemos

So, I can now parcel up the OPiZ as the house server and tidy up the sprinkler system.

I did note that the WeMOS did not come up first time I bombed the firmware.  That was sorted (it seemed) by selection the 4MB Flash option on ESP8266Flasher.  The ESP-12E on the WeMOS has a 4MB flash and I noted that there is a branch of the nodemcu frozen in time now for the 512kB chips – so go with the master branch if you have the WeMOS D1 R2.

I did also manage to break a hoodoo now that nodemcu does away with autoconnect for the MQTT.  The timer callback scheme works a treat.  I can reboot the OPiZ and the WeMOS will reconnect once emqttd is up and running again.  Of course, I have a LWT setup so that the emqttd server will tell the node-red if the WeMOS drops off the channel.

This is getting exciting now.

Okay, so I have changed my mind …

Posted in Arduino, ESP8266, Open Source can be professional on June 17, 2017 by asteriondaedalus

… it was fun for a while but …

So, dabbling in Lua on the ESP8266 was interesting.

The event driven stuff is clever.

However, the whole thing stinks because you cannot use the REPL cycle to take advantage of the scripting environment and the superior debugging opportunity that affords.

Especially around the niggly aspects of event processing and state problems inherent therein.

So, now the Arduino has the ESP8266, but especially since it now has a mqtt library, and mostly because we are only reading GPIO ports or setting bits on/off, I relent.

If you want to knock up a simple IoT gadget quickly, then Arduino plus ESP8266 are gold.

Short cuts

Posted in ESP8266, MQTT, NodeMCU, OpenSprinklette on December 18, 2016 by asteriondaedalus

The chappy doing OpenSprinkler gave me the best idea yet for the 24VAC to 5VDC to power the OpenSprinklette stack (Wemos D1 R2, fiddly bits including VAC2VDC and pullups, relay board).

Rather involves using a LM2596S-5.

I have in my bits drawers 10 LM2596S-ADJ based modules that go for US$2 a pop in packs of 10 so I will start with that for the prototype.

lm2596-psu-01-a-450x450

For the VAC2VDC the secret is to add a 3A diode (cathode to +ve volts input) of the PSU board.  It then likely passes for the circuit at the OpenSprinklette blog.

In fact, if you solder the pullups onto the two naughty GPIO pins you need to, either on WEMOS D1 R2 or the relay board, you could get by without an intermediate board.  There is still the conditioning circuits for the flow meters, but again, since we are using mqtt there is the option of a separate system for that.  I think we are already convinced that the rain gauge can twerp to an mqtt topic for example.  Although, there may be traction in a shield board for people who want no more than four zones and one unit – at least with the rain gauge input and 24VAC to 5VDC … oh and those pesky pullups.

Note we still need do something like string all the relay commons together now don’t we.

I guess the more interesting thing going on with the rain input of the OpenSprinkler is the use of a surge protection across the rain gauge input that has a Transient Voltage Suppression diode.  The selected value appears to be 48V which seems a lot but the gadget is used for ESD threats to the board (aka lightning – not strike likely but nearby EM field, up to a point).

This is actually necessary especially when there is  likely a long “antenna” from the rain gauge to the unit.

Might be less need if an ESP8266 is connected at the gauge and the solar panel and charger (we’ll need a battery to run at night time) are similarly “close by”.  Already solved in any event.  

Hmmm.  Lightning detection

Ah ha! Digital rain gauge spare parts!

Posted in ESP8266, MQTT, NodeMCU, Wifi on December 17, 2016 by asteriondaedalus
rain-gauge

Rock it to me baby!

So, get this, for US$15 you can get a rain gauge that does naught but yep, still yep and yep, then maybe nope.

That is, the cover has a funnel and water drips in and cycles the rocker!

 

simple

Simple tich?!

 

That likely needs nothing more than one of the ESP littlins …

esp8266

… to chirp tich/toch onto a mqtt topic.