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lesmondo

Member Since 09 Feb 2011
Offline Last Active Feb 08 2012 02:03 AM
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Posts I've Made

In Topic: Neduino & IN13 Nixie Bargraph

23 January 2012 - 03:29 AM

Hey

First off I should say:

Warning!!! This circuit uses high voltage that may well kill you if you don't understand what you are doing!!!!

Also, if you mess up the wiring and put 120+ volts into your netduino, it wont't be very happy.


The display is part of a larger project hence the schematic appearance. R4 goes to a PWM output pin, the Anode to the HV PSU output pin and gnd to the HV PSU gnd and netduino gnd. Just to re-iterate the warning above, if the schematic as-is doesn't make sense or you are not sure of the schematic or what voltage is where, you shouldn't attempt this.

Something I did miss was the transistor type. Any HV one will do - an MPSA42 or MJE340 seem a popular choice.

In the video, the HV supply module is in the top right connected to its 12V supply via the red and black twisted leads. The HV output is the yellow wire to the anode of the tube. Gnds are tied together and are the black leads.

The tube as supplied has uninsulated leads, mine are covered in some heat shrink sleeving.

If you want to know more about these cool tubes, google IN13 bargraph will turn up lots of links. I'll also add the datasheets to my blog a little later today.


How it works

The RC filter acts to 'smooth' the PWM output into a control voltage.

R5 controls the current through the tube which in turn controls the length of light displayed. 1K is a starting value, if you find that netduino output doesn't drive the tube fully, you can reduce it. Assuming the base of the transistor is at 3.3V (the output voltage of the netduino at 100% duty cycle) the indicator cathode current will be

I = (3.3 - Vbe) / R5.

for an IN13 (from memory) this should be 3-4mA to light fully. Taking Vbe = 0.7, R5= 1K will give you 2.6mA. You might want to drop this in steps to say 470R if you find your tubes are lighting fully (they vary a lot).

R6 is for the auxiliary cathode - this helps to stop the display from breaking into multiple blocks (something the IN9s do apparently).

Hope this answers the questions. And be safe :)

Les

In Topic: Response: Pinging... Error: No response from device

10 January 2012 - 06:50 AM

If you have not done so already, could you take a moment and upvote the issue at these sites?

Device becomes inaccessible after deploying 4.2.0RC3 Firmware

Flashing tinyclr 4.2RTM to Netduino fails

Thanks


Done.

In Topic: Response: Pinging... Error: No response from device

06 January 2012 - 07:09 AM

Hi Just to let you know, I've reverted back to RC1 since RC3 was giving me the No response error on XP - same issues as above. L

In Topic: Netduino SDK API

04 January 2012 - 05:30 AM

And here's how to add the SDK help docs to VS2010 for F1 context help. There's also some basic examples on my blog that you might find useful (a button, an led etc.) http://nerduino.word...mf-vs2010-help/

In Topic: Button OnInterrupt Reset

22 December 2011 - 07:44 AM

As i was using the on board switch i got it working by doing the following:

public static InterruptPort button1;
public static void Main()
{
	button1 = new InterruptPort(Pins.ONBOARD_SW1, true, Port.ResistorMode.PullUp, Port.InterruptMode.InterruptEdgeLevelLow);
			
	WaitForButtonPress();
}

private static void WaitForButtonPress()
{
	Debug.Print("Waiting for button press...");
	button1.ClearInterrupt();
	button1.OnInterrupt += new NativeEventHandler(button1_OnInterrupt);
	while (true)
	{
		Thread.Sleep(15);
	}
}		
private static void button1_OnInterrupt(uint data1, uint data2, DateTime time)
{
	Debug.Print("Onboard button pressed");
        WaitForButtonPress();
}



This might be of interest - a general purpose button class. http://nerduino.word...1/02/24/button/ (derived from http://geekswithblog.../09/142211.aspx )

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