Zippity do dah, zippity ZAPPP!

Posted in Hardware, Sensing, The after market on December 25, 2016 by asteriondaedalus

Looking at OpenSprinkler circuit, the use of SCR to control the solenoids appears to require the addition of TVS diodes a plenty.

That would be a design decision.

As OpenSprinklette is using relays to drive the 24VAC solenoids we need not apply protection there.

Nuisance factor though is that trying to source non-SMD bidirectional channeled TVS, for the rain gauge input, not so much fun.

For the prototype at least, without any SMD pads on the prototype shield, we are happier with DO-15 or similar package types for the protoboard’s pad spacings.

Luckily though AliExpress came to the rescue.   I have ordered a packet 100 x 36V 1500W bidirectional TVS for US$11.   Now the original design calls for 48V but the markings on the devices suggested unidirectional and the text supporting them did not mention bidirectional.  So, just in case I have ordered 10 x 39V 1500W for US2.80.  That’s the problem with AliExpress and working with penny market vendors therein.  You take what you can get.

So rain gauge and TVS on the way.  I finally decided the shield I am designing will have an input for a rain gauge for those you want a minimal four sector.  The idea of a rain gauge with an ESP8266 has not gone away though.  Where we are using the mqtt and node-red we can build up as we please – over time.


Small steps

Posted in OpenSprinklette on December 24, 2016 by asteriondaedalus

Going from hints provided, I added 1.2kohm pull-up resisters to 3.3v on a breadboard shield that currently sits between the Wemos D1 R2 and what appears to be a clone of the Seeeduino Relay Shield V2.

The pullups need to go on D3 and D4 (GPIO0 and GPIO2) of the Wemos board.

As expected on power up the two relays on those boards, on D3 and D4 (GPIO0 and GPIO2), will be have the NORMALLY OPEN contacts driven closed so on initialisation you will need to ensure all four GPIO are forced LOW to drive the relays to OPEN.

To ensure this happens, you will need to force all four GPIO to OUTPUT mode and then set them LOW.

The two inner led  for D3 and D4 (GPIO0 and GPIO2) on the relay board lit on power-up as expected.  One (GPIO0 or D3) flickers on power-up of board likely as it is party to the startup mode of the board.  Settles on after flickering off then on as part of the start-up.  Indexing as per previous blog rant (2,3,4,5).

I can vouch for ESPStudio connecting to the Wemos with the two pull-ups in place.  As I have been able to run short snippets to flip state of relays.

May be best to flash with board unattached for moment.

Now given the circuit design of the D1 mini relay shield and the seeeduino (or clone) are similar, hopefully we are safe to continue.


Xmas sales!

Posted in C.H.I.P. on December 20, 2016 by asteriondaedalus

Wow, a shield for your Arduino with Wifi and Airplay and Audio, down from AUS$159 to AUS$99 for Xmas!

Or just ask Mike Brady for Airplay on your US$9 C.H.I.P.!

No, not that “Mike Brady“.

Wow! An ESP-13 shield down from AUS$34.95!  Or a WEMOS D1 R2 for US$6.  US4.60 if you buy 5 at a time, and you get AUS$3.14 change from the price of the ESP-13.


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.


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


Posted in Sucky service Providers on December 18, 2016 by asteriondaedalus

Got back from run to Jaycar for parts for OpenSprinklette prototype.

Wife was browsing using FireFox.

Downloaded and installed it herself with no need for IT support from me or user groups – which she loathes.

She felt it was twice as fast as Chrome and, of course, she could do her banking – which she couldn’t do with IE(dge).

DOH di DOH di DOH!

Posted in Sucky service Providers on December 18, 2016 by asteriondaedalus

My wife complained that her Google Chrome browser wasn’t working.  So in typical IT support almost but not quite help I said, well goodness gracious me uninstall it and reinstall it.


She can’t reinstall.

Turns out an error message is raised whether you try to install with the cloud install or the desktop install.

So, I dropped her into the Google Chrome help group and connected her then searched to find, you guessed it, other people are having the same problem.

Her laptop is that brand spanking new HP Spectre we got a month ago when we went up to the hardware store … no they don’t sell them at hardware stores … you have to understand my wife’s motivations for coming along to the hardware store … it was then 3 hours of torture at half a dozen furniture stores as sales were on … then off to the hardware store, literally for 5 minutes … then off to get a printer cartridge … and an “accidental” HP Spectre purchase ensued.

Go figure, they only had the display model so we had to go across town to another store … another 2 hours of my fast closing life lost.

So, brand new HP Spectre, Windoze 10, and a pesky update of Chrome has likely come through and broken it.

Now the downloads from Chrome don’t work.

Of course, why doesn’t she use the browser formally known as IE(dge), well that’s because it fails to support the webpages my wife’s bank’s servers spit out.   How many billions of dollars does Microsoft have to make before it keeps up with the standards?  And the ultimate insult, they have that new constant automatic user has no control, no way, mechanism.

They just can’t seem to add standards compliance into that pipe (dream).

In any event, I marvelled at having to drop into a Google user group, of a company that makes literally billions of dollars, to watch the ritual of users turning on one another for obviously being stupid and cannot install the software.   You’re not entitled to “help”, not having paid, but you are entitled to what … solace?

Google haven’t admitted to botching the update nor the downloads.   Of course, it can’t be expected to work on every machine.

Who’s to say Microsoft haven’t done one of their naughty knobbling things?  So blasé, been going on so long, you just shrug and keep stumbling on.

And of course the HP Spectre is not exactly the type of machine my wife should expect Chrome to be targeting.

My wife doesn’t even like James Bond.

DOH di DOH DOH, DOh Doh doh, DOH di DOH DOH, DOh Doh doh, DOH DOh, DOH doh DOH!

Ah ha! Digital rain gauge spare parts!

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

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 tich?!


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


… to chirp tich/toch onto a mqtt topic.