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#59359 How to control netduino plus 2 over the Internet

Posted by baxter on 23 July 2014 - 09:19 PM in Netduino Plus 2 (and Netduino Plus 1)

What about DynDNS,
http://dyn.com/support/wizard/

http://www.tp-link.u...icle/?faqid=297
I haven't used it for a while, but I set it up for a Netduino Plus 1. It's fiddly to get going from behind your router unless you have a smartphone (or use a neighbor's network). Most consumer routers do not have NAT loopback so testing needs to be done from a network external to your local network. Or, in my case, I used a spare router running DD-WRT with NAT loopback for local testing. DynDNS is no longer free, but there are other services.

 

I don't see that this poses a greater security risk than other traffic coming in through your ISP.




#59355 Serial Issues

Posted by baxter on 23 July 2014 - 07:44 PM in Netduino Plus 2 (and Netduino Plus 1)

RS232 uses inverted logic; TX/RX idle logic low. Netduino COM ports idle high. Most PC serial ports are RS232 and they may or may not conform to the RS232 standard (+/- 12V). Measure the TX voltage on your PC serial port. If it is less than about 2.5V, then your problem is inverted logic. You can invert TX/RX with a 74LVC2G14 or a 74HC14 Schmitt trigger Inverter The simplest thing to do is just buy a USB to serial TTL adapter and forget the PC serial port.
 




#59340 change ip address netduino

Posted by baxter on 22 July 2014 - 06:57 AM in General Discussion

Open MFDeploy --> Menu:Target --> Configuration --> Network --> Network Configuration --> fill in the blanks 

Attached Thumbnails

  • Network Configuration.JPG



#59332 change ip address netduino

Posted by baxter on 21 July 2014 - 05:48 PM in General Discussion

Look under:

C:\Program Files(x86)\Microsoft .NET Micro Framework\v4.2\Tools\MFDeploy.exe




#59283 How do I connect Netduino+ to a pc wireless?

Posted by baxter on 17 July 2014 - 05:34 PM in Netduino Plus 2 (and Netduino Plus 1)

I really think the key to getting these pocket routers to work is to assign fixed, but different IP addresses (outside of the main router DHCP range) and disable DHCP on both. The other important ingredient is to let the Edimax establish itself on the network before connecting the Netduino. Ping it and make certain it is in the ARP table. I also find that it works equally well with a network configured Plus 1 or Plus 2.




#59272 NP2 Wireless Button/Switch

Posted by baxter on 17 July 2014 - 01:47 AM in Netduino Plus 2 (and Netduino Plus 1)

The Ciseco XRF has a 1km max range with the supplied whip antenna (300m with chip antenna). Other models with chip antenna are of the order of 100m (max). Cheap 433 MHz modules typically have 20-100m range (mostly toward the lower end) depending upon the power, antenna and obstructions.

 

Reading toward the bottom of the page, that Amazon combo has Specifications:
Transfers distance: 80m (100-200m to the max for open spaces)
Receiving distance: 200m (100-200m to the max for open spaces)
and also, the battery probably costs more than the combo.

Important Note: The remote control does not include battery because of the strict customs inspection. Please prepare a "23A 12V" battery for it. We appreciate your understanding and support. 

 

Edit: While looking at that page, I spotted another remote control (claims 100m),
http://www.amazon.co...13FQECK319ARBPC




#59260 NP2 Wireless Button/Switch

Posted by baxter on 16 July 2014 - 07:02 PM in Netduino Plus 2 (and Netduino Plus 1)

433 MHz
http://code.google.com/p/rc-switch/
http://www.amazon.co...r/dp/B00JL30QQU

If you need some intelligence at the remote end look at Pololu Wixels
http://www.pololu.com/product/1336

I have a pair of these and they work quite well up to about 50 ft.

This is a well regarded long range module,
http://shop.ciseco.c...le-xbee-shaped/
You can change the personality of the module by installing the appropriate firmware (Appendix 2: Dual Relay?)
http://openmicros.or...-llap-reference




#59180 NETMF SerialPort and "BreakState"

Posted by baxter on 12 July 2014 - 09:54 PM in Netduino Plus 2 (and Netduino Plus 1)

Success is sweet after a round of failures ...

 

My measurements with a BAT42 diode:

(1) Measure the interface TX/RX; it should be greater than 2.7V. ---> 3.0V
(2) Apply 0V(GND) to TX/RX. Measure RX; it should be less than 0.5V (0 to 0.5V) ---> 0.05V
(3) Apply 3.3V to TX/RX. Measure RX; it should be greater than 2.7V. ---> 2.9V
(4) Disconnect Netduino TX from TX interface. Apply 0V(GND) to TX interface.
     Measure TX/RX; it should be less than 0.5V (0 to 0.5V) ---> 0.03V

There is not a lot of margin on the high side when working with 3.3V, but enough.

 

Here is a Netduino VB 2010 simple serial text terminal I wrote to interact with something connected to the COM port. It's nothing fancy, but it works
https://www.dropbox....al Terminal.zip
You can translate it to C# with one of the online translators,
http://www.developer...t/vb-to-csharp/

 

You might consider the HC-SR04. It will probably be easier to work with than the SRF01 (no Break and no COM port, just an echo line)
https://www.dropbox..../HC-SR04_V1.zip
I translated the original C# to VB. The original link is in the program. I added some smoothing and statistics on the measurements.

 

I am glad that you are finally getting some hardware interaction. If nothing seems to work, it can lead to mountain of frustration.




#59169 New Modules Seen in the Wild

Posted by baxter on 11 July 2014 - 09:27 PM in Netduino Go

 

Mine has sat unused in its box since I excitedly bought one when it first came out. I expect it to stay there.

Mine also 




#59163 NETMF SerialPort and "BreakState"

Posted by baxter on 11 July 2014 - 09:01 AM in Netduino Plus 2 (and Netduino Plus 1)

Well I really can't  make out any thing out from your photo. I haven't tested the half-duplex circuit, but it may have problems operating at 3.3V due to the forward voltage drop through the diode and also the resistor value may need to be adjusted. I am pretty certain he designed the circuit for Arduino which has 5V I/O. I suggest you breadboard just the half-duplex circuit. You can then statically test it with your meter. Instantiate COM1 on Netduino and let it idle. You should measure 3.3V on TX and RX. Next, Connect TX and RX of Netduino to TX and RX of the interface circuit.

 

(1) Measure the interface TX/RX; it should be greater than 2.7V.
(2) Apply 0V(GND) to TX/RX. Measure RX; it should be less than 0.5V (0 to 0.5V)
(3) Apply 3.3V to TX/RX. Measure RX; it should be greater than 2.7V.
(4) Disconnect Netduino TX from TX interface. Apply 0V(GND) to TX interface. Measure TX/RX; it should be less than 0.5V (0 to 0.5V)

 

If your measurements do not conform to (1)-(4), then the circuit will not work with 3.3V. The TX line from Netduino will probably need to be level shifted to 5V before connection to the TX interface or the circuit modified.

 

I am more than happy to help you, but if you are just starting out, I would suggest buying a book such as this,
http://www.amazon.co...t/dp/0596153740
This is a very lucid starter book. You don't want to farm your project out to a consultant. Stick with it and you will learn a lot. This is a conceptually simple project; all you are trying to do is talk over a serial line. As I said before, the first step is to get the SRF01 working from your PC with the USB to serial adapter according to the web page instructions.

 

More on logic signal voltage levels:
http://www.allaboutc.../chpt_3/10.html




#59155 Can anyone recommend a rock-solid LCD display?

Posted by baxter on 10 July 2014 - 11:38 PM in Netduino Plus 2 (and Netduino Plus 1)

I have been using the BPI-216N/L Serial Text LCD for years. The COM port interface is about as simple as you can get.
http://www.seetron.com/products.html
It's a bit pricey and you can get something better with a serial interface for about the same price (look under Intelligent Display modules),
http://www.4dsystems.com.au/products
http://www.4dsystems...brief_R_1_1.pdf

 

I have the older version of this module and it is a very readable display.




#59149 NETMF SerialPort and "BreakState"

Posted by baxter on 10 July 2014 - 06:07 PM in Netduino Plus 2 (and Netduino Plus 1)

You are not going to be able to talk to the SRF01 from Netduino without the hardware break. I fired up Fritzing, made a schematic and connected the corresponding breadboard wires. The project is here,
https://www.dropbox....NXj2cVZn8bAJjYa

I am pretty sure it's correct, but no guarantees. Starting from a schematic, ratsnest wires are transfered back to the breadboard and you need to connect them up with wires. Fritzing is a work-in-progress and I find it very limited and cumbersome to use. I use Eagle Cad for all of my work.

 

In any case, you need to develop the capability to transfer a schematic to a breadboard. Here is a nice online free application for electronic design work,

http://easyeda.com/




#59117 NETMF SerialPort and "BreakState"

Posted by baxter on 09 July 2014 - 05:42 AM in Netduino Plus 2 (and Netduino Plus 1)

Wrong cable ... The one you linked is USB to RS232. I should have been more explicit. What you want is is USB to TTL. Something like this,
(1) http://www.ebay.com/...e-/261101529602
or this,
(2) http://www.mouser.co...j627GFcejHp0Q==
or this,
(3) http://yourduino.com...ct_detail&p=164

 

With the first two, you can plug your jumper wires into the end of the cable and then into the breadboard to bring the signal lines to the breadboard for connections. The third style can plug directly into the breadboard, but be careful that the header pins have enough depth and are not too far offset from the edge of the PCB. Most of my USB to serial TTL are like number (3). The RS232 version you ordered is not of much use for Netduino work. I would cancel your order if you can. The RS232 cable can be used for download with the Netduino Mini.

 

Serial RS232 and TTL are different protocols that are characterized by the logic state voltage. If you measure voltage with no transmission on a TTL TX line, it will be 5V corresponding a logic 1. For RS232, logic 1 will measure at about 2.7V or less. In most cases, USB to RS232 adapters do not conform to the RS232 standard. A further characterization is; TTL idles high and RS232 low..

 

Comment on Fritzing layout
==========================
Last post: Remove the blue wire. Netduino RX doesn't have anything to do with the BREAK.
Next to last post: Correct, but lose the RS232 adapter. See above comments. If you use it, you will need to add add a chip to invert TX and RX from/to the adapter.

 

I will try to dredge up my lost knowledge of Fritzing and try my hand at layout of the breadboard. This is turning into an intriguing problem.




#59111 NETMF SerialPort and "BreakState"

Posted by baxter on 08 July 2014 - 10:05 PM in Netduino Plus 2 (and Netduino Plus 1)

Remove the red power to the diode.

 

I would step back to square zero on your project and then take small steps. First establish that you can communicate with the SRF01. Go to http://www.robot-ele...m/srf01tech.htm
and download the terminal program under heading, Testing (it compiles and runs just fine on my PC). Buy a FTDI based USB to serial adapter and plug it into your PC. The driver should install automatically; if it doesn't, then install the VCP drivers. Other chip based USB to serial adapters will work, but you may need to download drivers. Hookup the SRF01 as shown in the circuit under heading, Testing. You can get power from the adapter. The adapter and I/O to the SRF01 connections are: Diode cathode (band) connected to adapter TX, anode connected to SRF01 I/O and adapter RX. Just like your jpg picture hookup, but substitute the USB adapter connections in place of the Netduino connections. This should work because the PC serial class has a software BREAK. I would try it, but i do not have such a weird part as the SRF01. If you can't get a response then your SRF01 may be bad.

 

Now, you are ready to move on. I would port the code of the PC terminal program to run on Netduino. We know that the AND gate works for a BREAK so substitute the GPIO = low code here

 private void SendBreak()
        {
            SerPort.BreakState = true; 
            Thread.Sleep(2);
            SerPort.BreakState = false;
        }

I would also use the half-duplex circuit (call it Interface) then

Netduino RX(D0)   ---------------- RX (Interface) --- SRF01(I/O)
Netduino TX(D1)   --- AND gate --- TX(Interface)  --- SRF01(I/O)
Netduino GPIO(D4) --- AND gate 

The output of Interface is a single line connected to SRF01




#59092 NETMF SerialPort and "BreakState"

Posted by baxter on 08 July 2014 - 02:49 AM in Netduino Plus 2 (and Netduino Plus 1)

Arduino SoftSerial has the capability to setup serial pins (TX,Rx) or (TX,TX) for half-duplex as I remember. Looking at that diode circuit again. I don't think it will work. Their C# demo program is running on a PC with a software BREAK available and maybe the diode hooked up as shown is required by the program. This is what I don't understand; Quote: "A small schottky diode is used to prevent the SRF01 trying to drive the S22/S27's output line (data from the PC)."  If this is true, it looks like they have the diode connected backwards. 

 

Here is a circuit for a single pin software UART,

http://nerdralph.blo...tware-uart.html
and the driver,
https://sites.google...asicSerial3.zip

 

From the web page analysis of the circuit (Read SRF01 for AVR), it looks like this should work. Make connections:
(1) Tx/Rx is the connection to the SRF01 I/O
(2) TX = Netduino TX
(3) RX = Netduino RX

So, in addition to your BAT85 purchase, buy a 2N3904 NPN transistor and a 10K resistor. You can then experiment with both circuits. It is quite possible that there is a property or setting lurking somewhere in the MF serial class to put the serial port into half-duplex mode. I haven't found it. In any case, you are doing useful work here.

 

P.S.

 a ) Does one leg of the diode need to connect to D0 and the other to D1 (i.e. RX/TX)?

 b ) How does the RX line of the sensor connect to the diode if both legs are already plugged in?

===

Bring D0/D1 out to a breadboard with jumper wires and build your circuit there. Diode connected between D0 and D1 on the breadboard then connect a  jumper wire between the anode junction and the SRF01 input.




#59081 InterruptPort/Events slow the first time

Posted by baxter on 07 July 2014 - 05:26 PM in General Discussion

Not VS 2013, but Using C# 2010 Express, MF4.2 and pushing the button on a Plus 2, yields nearly instantaneous debug output and led blink.

--> Button interrupt caught.




#59078 NETMF SerialPort and "BreakState"

Posted by baxter on 07 July 2014 - 04:48 PM in Netduino Plus 2 (and Netduino Plus 1)

I searched for the SRF01,
http://www.robot-ele...m/srf01tech.htm
you have not picked an easy part to start your hardware adventures. The problem is you are sending out on Netduino TX to SRF01 RX and SRF01 is sending back on the same line, but you are listening on the Netduino RX which has no connection to the SRF01. Hook Netduino TX/RX with the diode as shown in this circuit from the reference and it will probably work. The site looks to be pretty complete for interfacing the SRF01.

Attached Thumbnails

  • TX_RX Interface.JPG



#59031 NETMF SerialPort and "BreakState"

Posted by baxter on 06 July 2014 - 04:25 AM in Netduino Plus 2 (and Netduino Plus 1)

Here is a Netduino post that might interest you,
http://forums.netdui...mx-transmitter/
He is using the AND gate approach for the BREAK. Apparently it works because he has tested it.

 

Completely missed this reference ...




#59027 NETMF SerialPort and "BreakState"

Posted by baxter on 05 July 2014 - 05:55 PM in Netduino Plus 2 (and Netduino Plus 1)

Your connections are now correct ...




#59016 NETMF SerialPort and "BreakState"

Posted by baxter on 05 July 2014 - 04:57 AM in Netduino Plus 2 (and Netduino Plus 1)

Pin designations A and B are inputs and Y is output. The gates are grouped by 3 (A,B,Y) moving down from pin 1. You want 1A (pin 1) connected to TX and 1B (pin 2) connected to BREAK (or conversly, it doesn't matter). 1Y (pin 3) is the output of the gate connected to sensor RX. You need to move the white wire to 1Y (pin 3) next to the blue wire. Everything else looks ok.

 

I hope this works. It is a neat solution for a break thanks to Dave Tweed's answer on electronics.stackexchange.




#59009 NETMF SerialPort and "BreakState"

Posted by baxter on 04 July 2014 - 08:22 PM in Netduino Plus 2 (and Netduino Plus 1)

Frankly, I do not know if you can mess with the serial port parameters after you have instantiated it. Others may know. Re-reading the hardware on the TX line posts, I find the AND gate very appealing in its simplicity.

 

If I were trying to do this I would use the AND gate and;
(1) setup the serial port (COM1/D0,D1)
(2) configure a GPIO port as as an output port (say, D3)
(3) connect the GPIO port to input 2 of the AND gate , TX to input 1 and output to sensor RX
(4) in your sensor driver, include a BREAK command (default GPIO pin = high, must always be high outside of  BREAK)
(5) in the BREAK command code,
    ( a ) set the GPIO output port low
    ( b ) send text to the sensor equivalent to the required BREAK time
    ( c ) set the GPIO output port high
    ( d ) exit break command

5.b will send zeros in place of the text character. You need to workout the number of characters to send.

 

AND gate parts:
1 gate AND: 74LVC1G08
4 gate AND: 74HC08




#59002 NETMF SerialPort and "BreakState"

Posted by baxter on 04 July 2014 - 06:45 AM in Netduino Plus 2 (and Netduino Plus 1)

I forgot to include two references to do a break with some hardware on the TX line,

http://electronics.s...emitter-followe
http://electronics.s...me-periods?lq=1

 

As noted in the comments/answers, the circuits need improvement, but they allow control of your break with a GPIO pin. The AND gate suggestion of the of the answer in link 1 looks to be the best and simplest approach,
Quote:
"What you really want is an ordinary AND gate. When both inputs are high, the output is high, but if either input goes low, then the output goes low"

 

So,
gate input 1: TX, input 2: GPIO = high ---> gate out: TX = regular transmission
gate input 1: TX, input 2: GPIO = low  ---> gate out: TX = low/break (hold GPIO low for break time)

 

I don't know if this gives a genuine break, but it is worth a try.




#58974 NETMF SerialPort and "BreakState"

Posted by baxter on 02 July 2014 - 07:08 AM in Netduino Plus 2 (and Netduino Plus 1)

Notes collected on various forums for sending a break. It seems as though changing the UART to 1/2 or 1/4 of the actual line speed and then sending a single null byte will simulate a break. Sending breaks was in my  distant past and I really never tested break sending.

 

NOTES (sorry no attribution available)

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

 

(1)---------------
A serial break is not a character. It is a signal that can be sent using the
TX line of the device sending the break.

When a serial port is idle and no data is being sent the TX line is in a
logical 1 state. While data is being send the TX line rapidly transitions
between logical 0 and logical 1. Each frame of data takes a certain period of
time to send, depending on the bit rate of the connection. This is called
the "frame time" or "word time".

A break occurs when the TX line is held to a logical 0 for longer than one frame time.
------------------ End (1)

 

(2)--------------- Microsoft (PC)
Method 1
The International Consultative Committee for Telephone and Telegraph (CCITT) modem
recommendations require a break signal to be at least "2m+3" bits long, where "m"
is the nominal number of bit times in an asynchronous character, usually 10; this
means that the minimum break time is 23 bits, with no maximum specified. Usually,
much more than the minimum is sent, such as 100 or 200 milliseconds
(that is, hundreds of bit times at high data rates). The timer resolution in a PC
is sufficient for sending such "long" BREAK signals, but not sufficient to send
exactly 23 bit times.

 

Method 2
An alternative means of sending a BREAK signal of shorter duration is to temporarily
change the data rate in the UART to half or 1/4 of the actual line speed and then send
a single NULL byte. This is more precise than using SetCommBreak() and ClearCommBreak(),
but it has the disadvantage of corrupting received data during the time the BREAK
signal is being sent (because the received data rate is wrong during that time).
An application can change the date rate in the UART with a call to SetCommState().
The DCB structure passed to SetCommState() specifies the new data rate.
------------------ End (2)

 

(3)---------------DS2480B
If break is not available on the host UART then switching to
a slower baud rate and sending a zero byte can simulate a break. Switching to
space parity or changing to a 9-bit word length with a zero in the most
significant bit can also simulate a break.
------------------ End (3)

 

(4)---------------
If sending, you need to disable the TX function of the USART, set the pin as
an output and hold it low for the break period, then re-enable the TX function,
and you can start sending data.

If receiving you don't have to do anything too special... A break will come as a
received character with a framing error, and a value of 0x00.
------------------ End (4)

 

(5)---------------
You can change uart's baudrate to lower value and send 0x00 byte.
(e.g. 0x00 byte transmitted with baud=57600 is break condition for baud=115200)
------------------ End (5)




#58971 Bitconverter class causing crash/irresponsiveness.

Posted by baxter on 02 July 2014 - 12:48 AM in Netduino Plus 2 (and Netduino Plus 1)

You can also use,

byte B = 0xac;
String S = B.ToString("X2");
Debug.Print(S); //--> AC



#58962 ATTiny85 talking to Netduino?

Posted by baxter on 30 June 2014 - 06:27 PM in General Discussion

https://learn.adafru...oducing-trinket

http://www.adafruit....or-the-trinket/

https://learn.adafru...usb-serial/code





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