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31  Development / Other Software Development / Re: IDE 1.0.5 v 1.5.7 - Instantiating a class causes program to reset (using 1.5.7) on: September 22, 2014, 08:00:40 am
That something works isn't proof there isn't a bug, only counterexamples are definitive.
So you always have to keep in mind the possibility that your code has a bug that happens,
so far, to only show up in 1.5.7.   There could also be a bug in 1.5.7.

Finding a simple piece of code that breaks on 1.5.7 only would enhance the probability of
the latter, finding your code falls over in 1.0.5 sometimes would imply the former. 

Its all detective work, trying to narrow down the possibilities - although some bugs are
due to complex interactions and are hard to isolate, which may be the case here.

Alas I can't find anything about running lint with the Arduino IDE, but you are checking
compiler warnings?
32  Products / Arduino Due / Re: Due stops working with increased code size - MEGA is working with same code on: September 21, 2014, 08:22:34 pm
Beta software with bugs?  What's strange about that?
33  Using Arduino / Motors, Mechanics, and Power / Re: What Brushless Motor IC Chip should I get for a 48v Brushless motor? on: September 21, 2014, 08:20:27 pm
I looked at the datasheets for FAN7388, HIP4086. I like this option the best and I only need one of these driver IC's per motor right? along with the 6 n-channel Mosfets?

Between FAN7388, HIP4086 which one do you think is a better option for a 48v self balancing scooter and can you explain why?


Its your project, you have to decide these things really.  They handle different
voltages, different levels of gate drive, come in different packages, have different
deadtimes, and the HIP4086 has a charge pump so can work with no PWM present
(unlike the vast majority of MOSFET drivers).

High power bridges and inverters are fraught with the risk of failure, it takes fractions
of a millisecond to _vaporize_ a MOSFET due to overcurrent, for instance, if shoot-through
happens.  This means devices can explode if you get things wrong.

You need to start testing at lower voltages and current limits and use an oscilloscope to
monitor waveforms and check all is well before upping the power levels a step at a time.

With that level of power definitely use fast opto couplers in the logic signal paths to protect
your microcontroller should the MOSFET and driver setup go bang.

If you want an easier life buy a chinese hub motor controller.
34  Development / Other Software Development / Re: Set Speed Control of Brushless DC Motor using Servo Library on: September 21, 2014, 08:13:07 pm
thankyou so much .the above reply was very helpful.
but there is one other issue that im facing .. the code is running fine and motor speed is also controllable through servo.write() between 180-63(min) but at round servo 70-75 the motor speed fluctuates. when i checked the input voltage at the esc it was varying between 8-10V thus the speed keeps going up and down . im powering the esc through a variable dc adapter. what could be the possible issue ? is it the adapter or some fault with the esc ???

The ESC will probably be pulling current spikes that are overloading the DC adapter.
The drop in voltage then causes the ESC to adjust its behaviour.

Remember these motors have only a few turns of chunky wire, they can easily pull dozens of
amps without flinching, if only for a few microseconds, can your supply cope?  These
ESC/motor combinations are developed to work from high performance LiPo packs
which have little difficulty sourcing extremely high currents without much voltage
drop.
35  Development / Other Software Development / Re: IDE 1.0.5 v 1.5.7 - Instantiating a class causes program to reset (using 1.5.7) on: September 21, 2014, 08:05:56 pm
I never mentioned the compiler.  However is it different between 1.0.5 and 1.5.7?  Is it getting
different compile options between them?

Libraries - are they different?  I've only used 1.5.7 with the Due so haven't compared
1.0.5 with 1.5.7 directly at all.  Have you read all the release notes between 1.0.5 and 1.5.7?

Have you managed to get it repeatable with a small example?

You know 1.5.7 is in beta?  You may inadvertantly have become a beta-tester.
36  Using Arduino / General Electronics / Re: Atmega 328p-pu en Standalone on: September 21, 2014, 02:53:19 pm
The capacitors have to match the loading requirements of the actual quartz crystal
to work properly.  You have to compensate for stray capacitance on the board too.
37  Using Arduino / Motors, Mechanics, and Power / Re: What Brushless Motor IC Chip should I get for a 48v Brushless motor? on: September 21, 2014, 01:58:57 pm
You have started a new thread on this subject without having answered my
question in the last one:

"Where are your MOSFET drivers?"

MOSFET bridges / inverters need MOSFET driver chips to drive them.  For
3-phase you need either 3 half-H-bridge drivers or one three-phase bridge
driver chip.

These all take 12V supply, provide logic inputs and use bootstrapping to
drive the top MOSFETs (all the MOSFETs in a bridge should be n-channel).

Examples are FAN7388, HIP4086.

Don't even think of any other approach for driving a 1000W bridge.  You'll need fast
over-current shutdown too, so some sort of current sensor / comparator
to override the logic inputs.
38  Using Arduino / Motors, Mechanics, and Power / Re: How can I know the frequency of a RF module of motorized blind ?? on: September 21, 2014, 01:48:42 pm
Borrow an RF scanner or spectrum analyser?
39  Using Arduino / General Electronics / Re: Arduino to unlock car doors- What do I need to be safe? on: September 21, 2014, 01:45:53 pm
Yes they all have thorough power supply conditioning.  Or may come a cropper when the
alternator/regulator or battery next fails.  Its wise to be robust in that environment.

Usually good filtering is necessary anyway to keep all the noise out (for a radio/audio
system).  In general if the protection component is cheap, you use it - fuse, RFC, TVS diode,
linear regulator.
40  Using Arduino / General Electronics / Re: 2N7000 MOSFET Switch Does Not Turn On When Gate Voltage is Applied on: September 21, 2014, 01:34:52 pm
Well clearly they are not common, you see leakage current only.  In a real device with
a floating gate the behaviour would be less predictable.
41  Products / Arduino Due / Re: attachInterrupt get interrupted pin on: September 21, 2014, 07:32:35 am
Do you have any idea?

Thanks smiley

Erm, fix the missing line continuations?  Just \
add \
them \
to \
the \
end.
42  Products / Arduino Due / Re: No Device found on COM but Arduino is detected on: September 21, 2014, 07:30:14 am
I take it you've removed all connections to TX0 and RX0 now.

Normally an erase should put everything into a workable state for downloads, but
any issue with a USB serial connection it may be wise to disconnect, kill the
IDE, wait 30 seconds and restart, in case the USBserial driver has got confused -
a brand new connection should be in a known state.
43  Using Arduino / Project Guidance / Re: How to tackle curious project on: September 21, 2014, 07:21:31 am
There are other interconnectivity options, potentially cheaper than wires
or WiFi, such as ISM wireless transceiver modules like the RF12M, nRF24L01+

Running long wires has issues with noise pickup, drilling holes in floors and walls,
etc, so wireless comms may be advantageous.  There are drawbacks though
(security / privacy for instance)

Have a look at the "networking, protocols, devices" subforum perhaps?
44  Topics / Science and Measurement / Re: Recording adc data at up to 227.3 KHz on: September 21, 2014, 07:11:14 am
At that sort of speed I would imagine a good fast buffer driver/opamp into the
analog pin would help give maximum accuracy - at that sort of rate I think there's
only a few 100ns to charge up the sample/hold capacitor on chip.
45  Development / Other Software Development / Re: IDE 1.0.5 v 1.5.7 - Instantiating a class causes program to reset (using 1.5.7) on: September 21, 2014, 06:45:36 am
Sounds like something corrupted the heap before the call to new.  If that
new is the only thing that is heap-allocating after initialization then a corrupted
heap might only show up thereafter if the allocated instance happens to alias an
existing object/array.

However you are using MemoryFree I believe so the heap can't be completely
smashed.

The problem with C is that its all too easy to write to somewhere random as
array bounds aren't checked, leaving a timebomb for later in the execution.
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