"I have so much to do that I shall spend the first three hours in prayer."
Martin Luther
Tough days in the south of Tassie with runaway fires, uncharacteristic heat and stretched resources making for a difficult few weeks. There are thousands of hectares burnt already including one of our favourite sites, the Tahune Airwalk. We always encourage visitors to drive down past Geeveston and check out the walk - and we are hoping and praying that the area and the attraction can recover after the devastation.
We are OK at the moment, but tomorrow could be a tough day - we are the blue cross on the map below. For scale, Judbury to Glen Huon is around 6km.
Fighting on many fronts
We went into Huonville for supplies around 8:30pm last night, and there were hundreds of people in the evacuation centre, displaced from their homes further south. Many roads have been cut, including to Kym's work in Castle Forbes Bay. This is a quick pic taken from the side of the road nearing Grove.
The sun sets behind the smoke plume
We have many offers of accommodation for us and our domestic pets if the situation worsens - we'll turn on the fire pump and sprinklers and decamp to safer climes. Speaking of domestic pets, there's nothing like a dip in Mountain River when the mercury soars! Anyone getting sick of dog swimming videos yet?
"There is no perfection, only beautiful versions of brokenness."
Shannon L. Alder
People can be very disparaging about Chinese manufacturing (usually without checking their labels), but we've found this amazing country to be simply outstanding in the electronics milieu - reliable, well priced and very innovative. Most of our electronics blogging has been about success and only occasionally do things go wrong from the manufacturing end, and so we note that the following is a rare occurrence and is not indicative our experiences to date.
Recently we took delivery of one of our new favourite chips (when will it end?), the Atmega88 for the much reported upon clock project. We have been mostly buying in small lots as is our wont, thus sensibly mitigating any potential disasters. We normally confirm delivery and then at some later stage test the chips, which is definitely not best practise. We were therefore a little consternated when the little chips from this particular order failed to be recognised by our nifty new QFP32 programmer.
Also mentioned on a previous blog was our order from Tindie for a high voltage AVR chip recovery board made in Slovakia. The unpopulated kit board had been sitting idle but this scenario seemed like a perfect time to solder up all the components and test the tester (and the reticent chips)!
Nice soldering, poor result
When all was soldered we grabbed a "good" chip (Attiny2313) and used it as a guinea pig - the Slovakian device performed as expected, recognising and resetting the fuses. Then the moment of truth arrived and with much anticipation the QFP32 package was clipped into the holder and - nada (observe the mocking red light in picture)!
We've contacted the supplier (no joy), and after a little digging around we have found that these chips date from 2013 and probably have either been recovered from a previous source (recycled) or have maybe been subjected to some environmental stress that has rendered them unresponsive and thus useless.
The positives from a half day of mucking about are:
the soldering up of the Slovakian Wonder was fun
the HVPP/HVSP AVR "fuse doctor" works well
we learned more stuff
Many many people have contacted us about the furious fires festering away locally - thank you and we are safe at the moment and have a good fire plan. The smoke and ash hasn't been fun at all, but we are coping.
We've even been able to get out for our morning constitutional swim, walk and play!
“If ever there was a guilty age, this is it. Guilt and hysteria. And at the bottom of it all, like an evil dragon, lies Fear.”
Henry Miller
Assuming hysteria and hysteresis have the same etymology (they don't) is only natural given how frustrating and what maniacal fun it has been to amend the magnificent magnetic magic lamp project that has been a little dormant of late.
The original idea (for kids of course!) was to have a candle night light that can be turned on and off with a "magic" wand (a piece of dowel and a couple of magnets). The project stalled when we could not work out a way to reliably use a magnetic hall effect sensor (at the moment a 49E) as a switch.
The voltage from a hall effect sensor changes according to the strength of the proximate magnetic field as shown on the datasheet.
So it should be simple to ask an Attiny13a to keep an eye on a pin connected to the sensor and then wake up and be a candle when asked. The reality is that the analog signal contains noise which corrupts the message from the magic wand. See the pic below.
The top signal is typically noisy, and the red dotted line was how we used to check for wand usage - as a single voltage point. The resultant red digital middle output signal reflects the noise as the original analog input oscillates about the single point, confusing the microcontroller. However, if we can set a top and bottom voltage (as shown by the green dotted lines) then the noise becomes irrelevant and the digital signal is clean.
So next was research, reading, more research, watching and then playing. We settled on the LM393 comparator to be the Schmitt trigger that we needed for hysteresis.
A few iterations later and it works a treat!
All manner of bits connected
The next phase is to make a few prototypes for testing (in particular how long the batteries might last with a dormant attiny13a plus a listening 49E sensor and a live comparator in the circuit). It would be great we think to have a few "candles" about the place which can be activated at will with a single magnetic wand. Stay tuned.
“You never know what’s going to be in the garden in January when you’re looking at it in June.”
Corey Ann Haydu
Take billions of raspberries (slight exaggeration, but close), wash then cook gently with a wee bit of sugar and vanilla. Place in the bottom of mason jar, freeze, then add homemade yoghurt. Wait to savour the experience, then eat and sigh - thanks garden!
Now that's prolific
A few blogs ago we mentioned fire preparedness - well, we were able to put all the groundwork to good use when thousands of hectares burned over the new year and sent smoke and ash our way.
Thanks to the recent prep we were full bottle on keeping everyone safe - even the asthmatics. A bit scary to be in dusk around midday, but happy to be out the other side and all well. Thank you for all the calls and contacts to check on us.
