Posted by Rod Lopez on 13 April 2011 - 01:35 PM in General Discussion

In case anybody else has similar issues the solution is as simple as this:

Write("V " + V.ToString("F1") + " A:" + A.ToString("F2") + " W:" + (A * V).ToString("F1"));

...the funny thing is that ToString sometimes seems to return the value and sometimes the name of the type, that's why I didn't try it before.

Posted by Rod Lopez on 13 April 2011 - 12:26 PM in General Discussion

	float A = 0, V = 0;
	PowerSampling.GetPower(ref V, ref A);
	Write("V " +  V + " A:" + A + " W:" + A * V);

	float A, V;
	PowerSampling.GetPower(V, A);
	lcd << "V" << _FLOAT(V, 1) << " A" << _FLOAT(A,2) << " W" << _FLOAT(V * A,1);

Posted by Rod Lopez on 12 April 2011 - 02:14 PM in General Discussion

Hi guys, It seems to me like it would be great to be able to choose the de-bouncing algorithm. Charles makes a good point (and a great post) on how to do debouncing, but it does add to the complexity and cost of a prototype board. ...plus you may not not have the right ICs at hand. I would love to be able to throw cycles to the problem (at the cost of memory and perf) rather than having to change the board layout/part list if that'd be possible. For a final product it might not matter all that much, but in the prototyping stages it is handy to just have these things working out-of-the-box

Posted by Rod Lopez on 13 April 2011 - 12:19 PM in General Discussion

	static DateTime lastTrackerSwitch = new DateTime();
	static void OnTrackerSwitchButton(uint data1, uint data2, DateTime time)
	{
		if (time.Ticks - lastTrackerSwitch.Ticks < 150 * System.TimeSpan.TicksPerMillisecond)
			return;
		else
			lastTrackerSwitch = time;

		//Here goes your code, being called after debouncing

Posted by Rod Lopez on 10 May 2011 - 01:14 PM in Netduino Plus 2 (and Netduino Plus 1)

so I thought, my EE skills are a tad rusty, so didn't want to risk it Thanks!

Posted by Rod Lopez on 10 May 2011 - 08:59 AM in Netduino Plus 2 (and Netduino Plus 1)

I mean the Vin, I would hope not to toast the pin or its connections, right now I am peaking at around 150mA when all servo and display hell breaks loose So what I would like to know is if 300mA would be okay to take through the Vin.

Posted by Rod Lopez on 10 May 2011 - 08:34 AM in Netduino Plus 2 (and Netduino Plus 1)

Posted by Rod Lopez on 10 May 2011 - 01:03 PM in Netduino Plus 2 (and Netduino Plus 1)

Posted by Rod Lopez on 11 April 2011 - 08:24 PM in General Discussion

It seems like it was as Mario suspected, if all the incoming data is not consumed with a read() call it'll just accumulate and start consuming RAM, until it runs out. I connected a callback to RXOver but never got called, I'll get back if I can get the experiment in the right setup again (you know how it when you need to break some things in order to fix others

Posted by Rod Lopez on 30 March 2011 - 06:24 AM in General Discussion

Posted by Rod Lopez on 29 March 2011 - 11:32 PM in General Discussion

Hi there,
This is my first post here, so please let me know if I am posting in the wrong place

So, as to the issue...
I have a setup where I am using one of the Netduino COMs as serial interface to an external chip (an IMU), communication works, and everything is fine and dandy (a.k.a I get my data through the serial), but I eventually (pretty much at predictable intervals) get an 'Out of Memory' error.
I honestly thought that moving to a managed framework meant that you didn't have to care about your memory anymore, is that true? do I need to release / dispatch memory blocks somehow? Do I need to manually invoke the garbage collector?
Could you give a look to the code and tell me if I am doing something terribly wrong?

thanks!!
-rod

IMUSerial = new SerialPort("COM1", 9600, Parity.None, 8, StopBits.One);
IMUSerial.DataReceived += new SerialDataReceivedEventHandler(IMUSerial_DataReceived);
IMUSerial.Open();

//write IMU code
Debug.Print("Serial is " + (IMUSerial.IsOpen? "open" : "not opened"));
byte[] pip = System.Text.Encoding.UTF8.GetBytes("r");

Debug.GC(true);
while (true)
{
	IMUSerial.Write(pip, 0, 1);
	Thread.Sleep(100);
	
}

static void IMUSerial_DataReceived(object sender, SerialDataReceivedEventArgs e)
{
	byte[] buffer = new byte[10];
	IMUSerial.Read(buffer, 0, 10);
	String message = new String(System.Text.Encoding.UTF8.GetChars(buffer));
	Debug.Print(message);
}

Posted by Rod Lopez on 15 April 2011 - 09:35 PM in General Discussion

Posted by Rod Lopez on 04 April 2011 - 09:50 AM in Netduino 2 (and Netduino 1)

Posted by Rod Lopez on 12 April 2011 - 09:34 PM in Netduino 2 (and Netduino 1)

Hi Chris, Nope, I haven't updated the firmware (I am trying to keep my schedule for releasing something and I am afraid of the "beta" moniker) What I have done is check out the changes and follow the description of the fix to one of the bugs (surely the same you think) to figure out and avoid the bug at setup-time, and it does work as expected. I am pretty confident the firmware upgrade will make my fix redundant

Posted by Rod Lopez on 15 April 2011 - 09:29 PM in General Discussion

@Mario: It has been a really strange trip that one. I have finally managed to get things running, but I'll look for a trivial case that can reproduce the error I've been having (maybe it is some combination of software and hardware) My basic assumption is that, under normal circumstances, connecting an analog pin to a circuit where another analog pin is connected shouldn't change the value returned by the first pin. That assumption was broken in my Netduino circuit (where as I was having perfectly valid reading on an Arduino version). One of the main issues, I think, is that the analog sampling happens in a given moment in time, and I have a couple of switching circuits that could be producing parasitic frequencies, with a bit of luck I ended up sampling a few of those peaks. Your answer made me rethink the whole approach and eventually to figure out what was going on I will, though, try to document the issue if I can get a good repro case, I am sure the guys at Secret Labs would be interested.

Posted by Rod Lopez on 13 May 2011 - 10:34 AM in General Discussion

Hi guys, Chris: That was my assumption too, it is good to know. An overload is definitely possible (though I encountered the issue from early on proting from an Arduino setup) I am dealing with both robotics and power sampling so it seems reasonable a cable would have touched something it shoudln't. One question on the "damage", what are the chances the issue might be consistent (as in, would I be able to add a multiplier to the incoming signal and sure, loose precision, but use the pin ) or can it become totally random? Mario: The ref is plugged to 3.3. Seems a bit funky to have to connect physically though, is there any way to wire those internally? Software maybe? I might be answering the wrong thing though, I don't quite get what you mean by "+3.3V >= VRef >= Vin" if I read that a-la software it doesn't quite make sense to me

Posted by Rod Lopez on 17 May 2011 - 02:51 PM in General Discussion

3.3v has to be greater or equal than VRef, which should be greater or equal than Vin, the signs should be the other way around, or am I a bit confused?

Exactly what I mean and what the specs wants.
Why are you confused?

The reason why I am confused is that it sound like Vin is to be 3.3 volts or lower, which isn't enough to feed the Netduino in any case. That's what +3.3V >= VRef >= Vin tells me, anyway.

Btw, I did measure the resistances of all the pins, across ground and different pins, the input resistance returned by the multimeter is very high (non-measurable really). My guess is that some magic inside the AD has gone off, possibly not blown (I can measure in a fairly deterministic way) but definitely not in the right range.

There's one thing that puzzles me, though. It feels like the Netduino reports a lower voltage than it should. It is normally a bit lower (in any pin) than the voltage reported by either power source or multimeter, but, as the load increases (let's say the LCD screen that's fed by the Netduino goes on), the voltage reported by the Netduino decreases much faster than what's reported by the multimeter.
We are not talking about massive value offsets, mostly in the order of one-two tenths of a volt; but I am keeping track of battery charge and it gets sensitive to small voltage changes

Posted by Rod Lopez on 13 May 2011 - 09:27 AM in General Discussion

Finally I have had a bit of time to create a repro case.

What I have set up is very simple, an external power supply with a voltage divider (22k/10k), ground to Netduino ground and the divider being fed to an analog analog pin.
What I get is super funky:
-using any analog input but for a3 things seem to work all the time the way you'd expect.
-Reading from analog3 does actually (pretty much exactly) half the sampled value, but not only from the Netduino side (as in not a software-scaling problem), if you put a voltmeter to the divider, the divider's voltage does drop the moment the divider is connected to a3, otherwise the value is what you'd expect.
Is a3 special in any way? Is my board broken in the strangest manner? Qui lo sa?

Posted by Rod Lopez on 13 April 2011 - 08:57 PM in General Discussion

Posted by Rod Lopez on 13 May 2011 - 02:56 PM in General Discussion

Posted by Rod Lopez on 17 April 2011 - 10:56 AM in Netduino 2 (and Netduino 1)

Posted by Rod Lopez on 12 December 2011 - 08:44 PM in General Discussion

Posted by Rod Lopez on 12 December 2011 - 01:28 PM in General Discussion

Mario, I am not planning to run the device from a 9 volt battery, the battery for my usage is more of large marine type, with a connected solar charger and other loads, that's where the 20mAmp come from Regarding the UI, the device does have a few things attached to it, including a LCD and keypad, the way it is setup right now I raise an event on key pressed and that wakes up the display lighting and a couple of other things. The issue is that, if switching off the whole board, the Netduino wouldn't be able to wake up on time for the UI to flow nicely.

Posted by Rod Lopez on 12 December 2011 - 08:41 PM in General Discussion

Posted by Rod Lopez on 13 December 2011 - 03:54 PM in General Discussion