iPad Explodes - caution users

[fly_tornado]

I can imagine this argument goes back to the days of recreational goat herders 300bc with the old boys complaining about how unstable this papyrus stuff is near fire or how hard to read it is when it gets wet not like clay. clay is written to last.

 

 

[ahlocks]

I mean in lieu of paper after a dump F_T....

 

It's a bit like phone sex really. The edges smart something fierce...

 

 

[fly_tornado]

wooooossssh

 

 

[ahlocks]

Thought so...

 

P.S. My papyrus is bigger than your papyrus (just to get back to the usual aviation way of things)

 

 

[Guest Andys@coffs]

I mean in lieu of paper after a dump F_T.... It's a bit like phone sex really. The edges smart something fierce...

I bow to your superior knowledge of he matter....While not an apple fanboi....I wouldn't buy one to then try it as dunny paper....but whatever floats your boat as they say

 

 

[ahlocks]

The point is that paper is awesome.

 

 

[Guest Andys@coffs]

I knew that....but you really expect me to walk away from an opportunity to poke fun at you.. especially given how infrequent you moderatium magnificanti post! and besides NES has been quite of late!

 

 

[ahlocks]

Nope.

 

It's just that pulling F_T's tail should be a recognised sport too.

 

 

[Dafydd Llewellyn]

There's always 2 sides to every story.....Try and make that claim if you fly in an open cockpit.......I have lost maps overboard, followed by an instantaneous Brrrrp as the prop dealt with the offending map when trying to refold to cover the ground im currently over..... I'd need to be going a whole lot faster to have the cockpit wind grab hold of the ipad ....and in any event don't need to take out of the kneeboard cover or pick it up because it constantly always reflects the ground Im over..... but if it did go through the prop then navigation beyond my immediate area at that point of time is likely to suddenly become a whole lot less important:lost:

 

Andy

I've 50 years' experience in using paper maps, thanks; I converted the glovebox of my PA28, in the '80s, into a set of pidgeonhole slots to cope with them. WACs, VECs, VTCs, ERSA, the radio frequency chart, etc, etc. I used to spend hours re-folding them so they'd be right way out when I wanted them. A nightmare when you need to traverse a piece of controlled airspace and you need a different part of the chart in a hurry, because ATC wants an ETA RIGHT NOW. They are even worse to use in the confined cockpit of a glider; the compensating factor used to be that gliders cover the ground fairly slowly. But when you put a motor on one, it can manage 90 kts TAS. So it's either fit an autopilot to keep it right way up whilst one wrestles with maps, and where the H has the timescale got to? Or mount the mini ipad on the panel (there's just barely room to do so, and nowhere else to put it). In a glider, one is frequently looking at the map through a final glide computer, which is a further chore OzRunways can help with, with its glide range display. On the whole, I'd rather be watching for other traffic, and generally keeping my head out of the cockpit. Situational awareness is what it's all about, and the moving map is a vast improvement over paper - and you can leave the map display alone and ERSA becomes the sole piece of paper you need to look at. The more demanding the circumstances, the greater the advantage. Even better when it can display the traffic in one's immediate vicinity, plus the BOM weather radar display.

 

So I regard the GPS moving map (at OzRunways level of presentation) as just about the greatest improvement in aviation since Curtis invented the Aileron. I don't want it to get hung up on some lousy technical detail like a cigarette socket power adapter (what a piece of garbage to have to have in an aircraft!) ; I want to know what the alternative might be. Right now, there's no practical alternative to a mini ipad, because it's the only one that CASA accepts, at least for the flying I want to do, and it's the only one that fits in my cockpit.

 

So I make no apology for trying to discover a way to get around the problem, if indeed it proves to be one, so there will be an answer if it's needed. Others are under no compulsion to do anything whatever about it, if they don't feel like doing so. But thanks to this thread, I can see a way, and it will do them no harm if I give it a try. People are free to say "If God had meant us to fly, He'd NEVER have given us the railways", if that's what they feel, after all.

 

 

[nomadpete]

Dafydd,

 

If you intend to go with a linear voltage regulator, please get some advice on cooling. The heatsink required to cool your 18watts (in still air) is quite large. Whilst the linear regulator is a great way to smooth the pulses out (as long as pre-filtering prevents any spikes exceeding the regulator's max input spec), you will find that the same pulse suppression can be achieved with a normal good quality switched mode design. Also, the switch mode unit is available 'off the shelf' with all that suppression built in. Well, at least that is true if you buy a quality unit.

 

I have not yet seen data on the Jabiru or Rotax regulators.

 

However, the Rotax 912 coils that I replaced were a three phase type branded Ducati.

 

"Normal" motorcycle regulators ( and I expect that Ducati would design their coils to suit this) rely on a 'short circuit' type regulator. I have tested these on motorcycles. NOT in ROTAX. These work by triggering a SCR to short each coil when the terminal voltage reaches 14 volts. It does this each cycle of the output voltage. So you get pulses of 14 volts going to the battery and the battery 'holds over' until the next pulse of 14 volts. Any excess power is dissipated in the coils themselves. I have put a oscilloscope across it and there are spikes of about 20 volts superimposed on the switching instants. You will find that any good automotive plugin device should not be bothered by this. I am aware that other small engines use single phase of the same concept, and similar regulators. Note that this is not a true switch mode regulator. Maybe it could be called a shunt regulator. If a true switch (series) mode regulator was employed, the potential generator coil voltage could spike much higher when the regulator pulses off. I would expect that the coils would have to be designed with better insulation to withstand this. Also there would have to be a spike suppression of some sort, but that is just an assumption.

 

Pete

 

PS don't use cigarette lighter sockets

 

 

[Dafydd Llewellyn]

Dafydd,If you intend to go with a linear voltage regulator, please get some advice on cooling. The heatsink required to cool your 18watts (in still air) is quite large. Whilst the linear regulator is a great way to smooth the pulses out (as long as pre-filtering prevents any spikes exceeding the regulator's max input spec), you will find that the same pulse suppression can be achieved with a normal good quality switched mode design. Also, the switch mode unit is available 'off the shelf' with all that suppression built in. Well, at least that is true if you buy a quality unit.

I have not yet seen data on the Jabiru or Rotax regulators.

 

However, the Rotax 912 coils that I replaced were a three phase type branded Ducati.

 

"Normal" motorcycle regulators ( and I expect that Ducati would design their coils to suit this) rely on a 'short circuit' type regulator. These work by triggering a SCR to short each coil when the terminal voltage reaches 14 volts. It does this each cycle of the output voltage. So you get pulses of 14 volts going to the battery and the battery 'holds over' until the next pulse of 14 volts. Any excess power is dissipated in the coils themselves. I have put a oscilloscope across it and there are spikes of about 20 volts superimposed on the switching instants. You will find that any good automotive plugin device should not be bothered by this. I am aware that other small engines use single phase of the same concept, and similar regulators. Note that this is not a true switch mode regulator. Maybe it could be called a shunt regulator. If a true switch (series) mode regulator was employed, the potential generator coil voltage could spike much higher when the regulator pulses off. I would expect that the coils would have to be designed with better insulation to withstand this. Also there would have to be a spike suppression of some sort, but that is just an assumption.

 

Pete

 

PS don't use cigarette lighter sockets

Thanks, Pete; however the cooling issue will be nine times less if I'm converting six volts to five volts, rather than twelve volts to five volts. And yes, I'm familiar with the use of heat sinks; I used to be in charge of the CSIRO F-27, in which we had three 24V DC to 240V AC solid-state inverters, about 5 KVA each, to cater for the scientists who insisted on designing their flight gear to run on 240 V. This also showed me how lousy the waveform can be from such equipment, and what problems can arise from that. We used to call one of the scientists "Captain Kilowatt". I'm also familiar with the use of BIG SCRs to drive vibratory feeders that feed iron ore into blast furnaces or rocks into gravel crushers.

 

The form of voltage regulation you describe is used by Jabiru, I believe, but I think its ripple problem is mild compared to the single-phase setup on the Rotax 582, despite the high RPM of the latter. I'd assume they switch the coil to ground, rather than to open circuit; they can't be that stupid. I consider cigarette lighter sockets suitable to use for throwing at stray dogs, etc.

 

 

[Guest Andys@coffs]

If you wanted to explore switch mode regulators Jaycar sell a 5V 3A one that requires 4 external components and operates at 77% efficiency. It has a switching frequency of 52kHz which is a long way from anything we are likely to be interested in frequency wise.

 

LM2576 is the chip.

 

 

[fly_tornado]

 

what i love about aviation, monetizing grand fathers fear US$700 plus fitting

 

 

[skeptic36]

ever tried a clay tablet, or an iPad for that matter, F_T?

An iPhone is much better, you can set it to vibrate........

 

 

[Old Koreelah]

"...don't use cigarette lighter sockets"

 

...what else is available to charge an iPhone or iPad?

 

 

[sfGnome]

Well, there you have it . . . .One small point could perhaps be (I'm speculating here) that many of the cigarette-lighter style adapters offer two USB outlets - which may be a way of exporting the "wasted" power and thus reducing the heat, provided a load is connected to each of the outlets; added to the liklihood that there's a thermal shutoff built into the things - which would mean that they will likely to be charging less than half the time. My reading of all this is that if your cig. lighter adapter is charging full-time and staying nice and cool, it's likely to be a switch-mode device, and therefore likely to be putting voltage spikes into your ipad. If it's getting hot & bothered & only charging part-time, especially if it's only driving one outlet, it's a "linear" type, and probably not putting voltage spikes into your ipad. The 2.1 amp ones for the ipad will be far more obvious under this crude test than the 1 amp variety for a GPS or whatever.

As Malcolm Frazer said, "Life was not meant to be easy". Why not use a pair of 6 volt batteries in series, and run an LM317K linear regulator from each of the 6 volt halves, for the ipad & GPS? That gets the waste heat way down - to about 3 watts, instead of 27 for the two outlets. I'm planning to build my own L-C filter for the 12V supply to the radio & transponder, including crowbar protection; ferrite toroids are remarkably cheap, and I have some 25 MFD 450 volt polyethylene film capacitors laying about . . .

Dafyydd, please don't take what I said as implying that linear is the better way to go. Good switchmode supplies are the bee's knees. They'll cope with the small repetitive spikes that the Sport Pilot article was talking about (as long as they are not designed to be borderline at 14V like a real cheapie might be), and they are no more susceptible to to the kV spikes of startup and shutdown than a linear reg.

The biggest problem with running a linear reg off a 6V battery is that linear regs require a certain level of step-down, and even the best ones will be borderline at 6V. As soon as the battery voltage starts to droop, so will the output and the iPad will start getting very iffy. Switchmode reg, on the other hand, will keep supplying as the input voltage droops (for a while at least).

 

 

[Dafydd Llewellyn]

Dafyydd, please don't take what I said as implying that linear is the better way to go. Good switchmode supplies are the bee's knees. They'll cope with the small repetitive spikes that the Sport Pilot article was talking about (as long as they are not designed to be borderline at 14V like a real cheapie might be), and they are no more susceptible to to the kV spikes of startup and shutdown than a linear reg.The biggest problem with running a linear reg off a 6V battery is that linear regs require a certain level of step-down, and even the best ones will be borderline at 6V. As soon as the battery voltage starts to droop, so will the output and the iPad will start getting very iffy. Switchmode reg, on the other hand, will keep supplying as the input voltage droops (for a while at least).

Yes, thanks for that; I'm looking at low-dropout regulators at the moment. The ones I've found so far won't handle more than 6.5 V input. Bear in mind that whilst the engine is running, the battery voltage is going to be around 7 volts, not 6 volts. A 7 AH Yuasa in good condition will take about one hour at 2 amps load to droop to 6 volts from a full charge; in a motor-glider application, one is likely to have to run the motor every so often; in still air, about every 20 minutes; in more favourable conditions, maybe every hour; you have to watch the battery voltage to make sure you have enough battery to re-start the engine reliably. The ipad does not need to be on charge 100% of the time; mainly, I think, you want it to be at full charge when you turn the motor off after takeff and climb to where the lift is (usually, fairly close to cloudbase); that's probably going to be about 15 minutes of engine run time, plus whatever additional time the 6V battery can stay above the dropout voltage - so if the system gets the ipad to full charge within about 3/4 hour of takeoff, and tops it up periodically throughout the flight, it should not be necessary to recharge every night. That's essentially the aim.

 

If there's an issue with the ipad battery from the inherent noise from a switch-mode supply - and that's an unknown at this stage; lacking data on the maximum noise level it can tolerate, one cannot evaluate that - it seems advisable to at least research low-dropout linear regulators. It may well be that I can use a high-quality TI or similar switch mode regulator, and if so I can dispense with the 6V battery setup. I'm still in research mode; however I would not have known where to start, without the thread.

 

 

[horsefeathers]

What a great thread.

 

I've been getting random (phantom) reception noise every few minutes on my radio of late. (Running a Blue Top 582, btw)

 

I had, till this morning, a 12v iPad charger plugged into my indash cigarette lighter socket. No phone/iPad was plugged into this charger.

 

After reading this thread, I removed the charger, and the phantom receptions disappeared.

 

Plugging it back in caused the phantom receptions to reappear.

 

So, either I will try to find a high quality charger, or will use my 11000 mA battery pack for my iPad mini, and forgo the cigarette lighter charger

 

================================================================================

 

On a similar vein, is there a quality voltage regulator or indeed any other device that I can use to smooth out the choppy 582 alternator output?

 

 

[frank marriott]

What a or will use my 11000 mA battery pack for my iPad mini, and forgo the cigarette lighter charger

Battery back solves charger problems. Doesn't address the need to charge overnight though.

 

 

[Dafydd Llewellyn]

I think I have a workable answer: You use one of these http://www.powerstream.com/dc-dcz0603.htm to drop the 12 volt nominal to 6V precision; and you then use a linear regulator based on an LT 3083 to drop it to 5V with nil output ripple.

 

This runs straight off the 12V battery and reduces the heat loss to a minimum (about 3 watts) and has nil output ripple. Don't need to split the 12 V battery into two 6V halves.

 

 

[Dafydd Llewellyn]

What I don't yet know is whether it is necessary to limit the output current for the ipad supply to 2.1 amps.

 

 

[Guest Andys@coffs]

Dafydd are you sure about 2.1A.....I just checked my Ipad 3 charger and its rated at 5.2V and 2.4A giving approx. the rated 12W.

 

I have used this one to charge the wifes iphone5 which only needs a 10W charger and it works fine, just a bit faster....

 

Andy

 

 

[Dafydd Llewellyn]

Dafydd are you sure about 2.1A.....I just checked my Ipad 3 charger and its rated at 5.2V and 2.4A giving approx. the rated 12W.I have used this one to charge the wifes iphone5 which only needs a 10W charger and it works fine, just a bit faster....

 

Andy

No, Andy, I'm not sure - that's why I asked. The wall charger that came with my ipad mini is Apple A1402, which appears to be 1 amp rated. There are backup batteries for them, which would suggest that the ipad itself may have some form of charge - current limiting. I simply do not know whether it's safe to plug the thing into a 5V source of arbitrary current capability.

 

 

[Guest Andys@coffs]

actually a point worth making is that the apple supply isn't just a supply, it has a resistive network on the USB Data pins that lets the ipad know its a sanctioned device that is charging it.....That network isn't difficult and I'm sure a bit of googling or reverse engineering a $2 ebay special will give you what you need. without the right treatment of the USB Datalines the ipad will kick up a message bleating about the charger....

 

http://en.wikipedia.org/wiki/Universal_Serial_Bus#Charging_ports_and_accessory_charging_adapters

 

is a useful page that covers that type of Apple ploy to keep the faithful lining up to pay apple prices....

 

Blackberry do the same thing, you have to install a crappy driver on a PC, without it the USB plug in charger wont charge.

 

Andy

 

 

[sfGnome]

For voltage and current, think of it this way. The source supplies the voltage and the load draws the current. As long as the supply can supply as much current as the load needs, then everything is fine. You could have a supply that is capable of supplying 1000A and it would be quite safe to connect to your iPad, because it is the load (ie the iPad) that controls the amount of current drawn. On the other hand, if the supply can't supply enough current to keep the load happy, then the voltage will droop and all bets are off. So, if your genuine Apple wall charger that came with it is rated at 1A, then it means that the mini iPad must require less than that amount, and any cigarette lighter charger that can supply that much or more is fine (all other previously discussed issues being already accounted for, of course).