Here is a video example I've been meaning to upload. It uses two Netduino's. Each Netduino contains a Gainspan GS1011MIP module and an RGB LED. The Netduino's are powered from 9v batteries, so they are completely wireless.

In this video, the Netduino's connect to each other via an ad-hoc Wi-Fi connection- there are no routers or computers involved in this demo. At the start, each Netduino powers up and sets its LED high. After a short initialization delay, the first Netduino then sends a TCP message to the other Netduino to set a random color for its LED. The second Netduino responds and sets its color. Then the second Netduino sends a TCP message to the first Netduino to set its LED to a random color. The first Netduino responds by setting its color and then sends a message back to the second Netduino, etc., etc...

The effect is a visual representation of the ad-hoc TCP messages between the two Gainspan modules. This could be the basis for a wireless sensor network. I did a rough test in the backyard and these modules can talk back and forth out to 150 feet apart in an open-air scenario.


I moved the modules around in the video just to demonstrate that it is completely wireless. It is kind of a long video, but still cool. My bag of Doritos and my iPad make a brief cameo appearance. Lol

Netduino: Gainspan ad-hoc Wi-Fi communications

I just got a gainspan 1011 breakout board in the mail to give my netduino some wireless comm. I looked at the datasheet and it appeared all I had to do to it was put power and rs232 on it and start throwing AT commands down the serial connection. I'm using my netduino for powering the gainspan board. I'm using a rs232 cable with flying leads coming from my computer and a program called RealTerm (v2) for talking to it. I started with the my settings at 9600,8,n,1. When I send the "AT\r" command, I just get jibberish back. It looks like the baud settings are wrong, but those are the default settings from what I can tell. Does anybody have any ideas as to what I'm doing wrong?

According to the documentation, the module requires repeatedly sending the "AT\r" command until an "OK" response is received. Are you sending "AT\r" multiple times until you receive "OK"? If you are, and you're never getting an "OK", it sounds like a baud rate or wiring/setup issue.

A relay works. The problem is that the relay contacts are not going to last very long if I use this method. Can anyone think of any other way to do this?

Netduino touches my iPad.

See video action here: Netduino triggers iPad Drums. The ticking sound is not a metronome- it is the 9vdc relay I'm using to open and close the Ground.

I also notice that if I increase the speed, sometimes it misses hits on the touchscreen. Does anyone know why? Other than the anti-static foam, should I use other materials to get a more reliable contact?

Darrin, I tried OutputPort, and nothing. I tried TriStatePort, and it triggered a couple of times, but not reliably. I'm going to try a relay now. Thanks, Nick

Andy, The firmware update program is called gs_flashprogram.exe. It is simple to use. Let me know how it goes. Nick

Anyone know where I can get a netduino t-shirt?? I use this mcu so much I'd like to show my support. It would be a nice supplement to my Sparkfun sweatshirt.

Hi,

Can you tell me the commands I need to pass using the usb ttl device to firstly connect to my network and secondly do the firmware update.

I have connected to the device and have found my network but can't figure out how to connect to it?

Also I have no idea what I need to do to flash the new firrmware on to it?

I am using the tera term app that came with the firmware update files.

Thanks in advadance your help is much appreciated.

Andy

If you're using a USB-to-TTL connection, just connect it directly to the Gainspan. You do not need to connect to any network. You're using UART comms at that point.

If you have the full documentation, the FIrmware download should have provided a com port program to use for updating the firmware (note: this is not the Tera Term app; it is another app in the download files. SOrry, I don't remember the name of it at the moment).

Just so you know what I need to do:

• Connect anti-static foam directly to the display of an iPad (the anti-static foam is the stuff that IC's are normally mounted on when shipped)
• Connect a wire from Ground to the anti-static foam
• Trigger the Ground connection on and off

This makes the Netduino "touch" the iPad touchscreen. I've already tested this simple scenario and it works, but I have to physically touch the wire to Ground and remove it. I need some way of doing this with Netduino programming.

I have an iPad drums application, and my current idea is to make an automatic drum sample controller with the Netduino;

• Connect anti-static foam to each drum kit point on the iPad display
• Connect separate Grounds for each wire
• Trigger these wires individually so I can press each drum-kit item separately (high-hats, cymbals, bass drum, etc.)
• Record and play back the drum sample on the Netduino, sort of like one of those pianos that plays automatically.

This would also allow me to trigger the drum kit with other materials by using pressure sensors. Ultimately, I could use regular drum sticks on other materials to play the electronic drum kit on the iPad.

The problem I'm solving with this: the iPad display is small, and obviously I cannot smack real wooden drum sticks directly onto the iPad display, so I have to use my fingers to play the drum kit, which is not true to a real drum set, and it is cumbersome.

This would open up the ability to create a small electronic drum kit that could be played with real drum sticks. All the sounds are already there on the iPad; I just need to implement the electronic connections to "touch" the iPad display.

What do you think? Dumb idea? Cool idea? Useless idea?

Has anyone done anything like this before? Any tips?

Thanks!

With Netduino, how can I connect a single wire such that I can switch whether or not the wire is going to ground? Would I use a transistor? The wire does not need any voltage connection- it is just a grounded/un-grounded wire depending on whether I "switch" it between grounded or un-grounded. The other end of the wire is not connected to anything. Thanks!

Hi,

I have just got a gainspan module from sparkfun, and I wondered if you could help...

Firstly can you tell me which version of the firmware do I need (I have the NDK now), I have downloaded both but am not sure which one to use; the Mxp or MEE?

Also how do I then update the firmware?

Finally do you have an example web script as I have not really done much with websites before and don't really know where to begin with that side?

Many thanks,

Andy

Andy,

Out of the box, you do not need to update the firmware. If you need the current functionality, such as Bulk Data mode and others, you'll need to update the firmware.

The part number should be written on the device. Mine is a GS1011MIP, so I would use the MxP firmware. The part number just indicates whether it uses an internal or external Power Amplifier (PA) and whether it uses an external or PCB antenna. For example, an MIP has an internal PA with PCB antenna. An MEE has an external PA with External antenna. See also http://www.gainspan....e/s_modules.php

I update the firmware using a 3.3v USB-to-TTL adapter and the communication software provided with the Gainspan software download. I can't remember the name of the software at the moment but it is included in the download, as long as you have a login and have signed the non-disclosure agreement. Just plug the USB end of the adapter into the computer and wire the 3.3V, Tx, Rx, and Gnd from the ttl adapter to the corresponding pins on the Gainspan module, with Tx to Rx, and Rx to Tx.

As for the example web script, maybe describe what you're trying to do exactly and I can try to help.

Nick

I thought we need $6000.00 tool to compile native code. What exact hardware and software is required to do this? Can someone please provide a bulleted list?

Thanks for all the responses. Being new to Netduino it seems to me that their is not a lot of wifi compatible hardware out there for the netduino.

I have seen the following "Mantis" bot at this site.
http://ttjcrew.com/2...robot-controls/

They are using the netduino plus (with the ethernet port) and used a 12 volt car battery in addition to a wireless router.

I was thinking that this might be an alternative way of acheiving my objective.

I purchased my netduino yesterday and can't wait for it to arrive, so I can start playing.

Regards

ScottBrady

If the physical size does not hinder the project, then using a wireless router with a Netduino Plus is a good method. I think you'll find Netduino to be a useful microcontroller platform. Good luck.

Nick

I use the Gainspan GS1011 Wi-Fi module (http://sprkfn.com/p10505) and it works well with Netduino. It operates on 3.3VDC and connects to the UART and uses simple serial commands for communications. I've even gotten it to function as a very simple WiFi web server by serving the pages from the onboard Netduino microSD card.

I see there is an Xbee WiFi module available, but I have never used it and I do not know if it is compatible with Netduino.

I'm using the gainspan 1011. I followed your source code and have tcp working nicely, thanks! I'm trying to get the httpsend feature working to send an http post. I setup a php script that accepts two fields and I've verified it works using putty. So far, the php script is telling me I'm sending an empty message. So, I'm definitely talking to the server, just not sending any data. I think maybe I've got the escape sequence incorrect. Here's the relevant commands I'm sending the gainspan:

at+httpconf=20,User-Agent: Mozilla/4.0\r
at+httpconf=3,keep-alive\r
at+httpconf=11,<myhost>\r
at+httpconf=7,application/x-www-form-urlencoded\r
at+httpopen=<myhostip>\r
at+httpsend=0,3,10,/test_post.php,23\r\x1BHname=myName&info=myInfo

Any suggestions? I'm not sure what to try next.

Hi, unfortunately I have not used the built-in http features of the Gainspan. For my Gainspan projects I rolled my own http communications.

I've been advised that I can create a "super-interrupt" pin on the Netduino by hacking the firmware. Please see quote from Chris Walker below:

...make that pin an FIQ-accelerated pin...and then use an FIQ handler in your code to count the number of pulses. Then you can easily create a "startcount" and "StopAndGetCount" managed code method to capture the values. FIQs will activate in less than one microsecond, will supercede the .NET MF runtime and...as long as they're quick...will not interfere with your code. We're using them for software PWM in an future update of the firmware, for instance.

Chris et. al,

How do I start with getting this set up? I downloaded the .Net MF Porting Kit and the Netduino Plus firmware, and I've copied the Netduino firmware into the Porting Kit directory. Now I need to know how to modify the firmware to get this operational.

X10 is mainly using PLC technology. An RF standard is available but the PLC version is the most used, and still very much in use. I use it, but I also use devices communicating over 433 MHz RF, using hardware from RFXCOM.

Oops! For some reason, I keep mixing up X10 and Zigbee. Don't ask me why because I have no idea why. I guess Z's and X's cause confusion.

So, when I said that personally I would choose X10 over PLC, what I really meant was I would choose a newer communication protocol over PLC or X10 which are dated technologies even though they're still very much in use. We could also say that DOS is still very much in use, but would you really want to write new software for DOS? Well, maybe you would, but I wouldn't.

I'm looking at a device that runs at fast-mode 400kHz i2c. Is it possible to integrate with Netduino?

Ok, this:

            float Sv = (float)(Math.Log((float)0.3*iso,2));
            float Bv = (float)Math.Log(lux / (float)0.3 * (float)14, 2);
            return ((float)(Bv + Sv));

returns the same 14.7439928 value I am getting from the .Net MF version of Log. So it looks like initially I wrote the Windows Forms function incorrectly.

14.7439928 is not the value I expected, but that is a whole other issue.

float Sv = (float)(Math.Log10((float)0.3 * iso) / Math.Log10(2));

This (and the corresponding code in your first version) is redundant - that's just the binary logarithm of the first argument.

That is because I need to calculate Log2 to get the Film Sensitivity. The actual equation I am trying to calculate is:

Film sensitivity (Sv) = log2( ASA / 3.125 )

(see APEX units)

This code is ported from Arduino code and Arduino does not have a built-in Log2 function, hence to get Log2, the code uses the fact that the logarithm of any base other than the natural is the natural logarithm divided by the natural logarithm of the base.

In C#, I could indeed re-write that line as:

float Sv = (float)(Math.Log((float)0.3*iso,2));

But I still don't have an answer as to why Math.Log returns the expected value, but that other .Net MF code does not. I may just have to solve and then divide by 2 for now.

So, I am trying to use the Log function at the bottom of this page. So here is the Log code I am using:

public static double Log(double x, double newBase)
        {
            // Based on Python sourcecode from:
            // http://en.literateprograms.org/Logarithm_Function_%28Python%29

            double partial = 0.5;

            double integer = 0;
            double fractional = 0.0;
            double epsilon = 2.22045e-16;

            if (x == 0.0) return double.NegativeInfinity;
            if ((x < 1.0) & (newBase < 1.0)) throw new ArgumentOutOfRangeException("can't compute Log");

            while (x < 1.0)
            {
                integer -= 1;
                x *= newBase;
            }

            while (x >= newBase)
            {
                integer += 1;
                x /= newBase;
            }

            x *= x;

            while (partial >= epsilon)
            {
                if (x >= newBase)
                {
                    fractional += partial;
                    x = x / newBase;
                }
                partial *= 0.5F;
                x *= x;
            }

            return (integer + fractional);
        }   

Now, I am using the above Log code for the following function:

        static float calc_ev( float lux, int iso ) {

            // calculate EV using APEX method:
            // Ev = Av + Tv = Bv + Sv
            //lux = 19.6F;
            //iso = 100;

            // We'll use the right-hand side for this operation

            // Bv = log2( B/NK )
            // Sv = log2( NSx )
            float Sv = (float)(Log((float)0.3 * iso,10) / Log(2,10));
            float Bv = (float)(Log((lux /  (float) 0.3 * (float)14),10 ) / Log(2,10));

            return( (float)(Bv + Sv));  
        }

If I run calc_ev( 19.6F, 100 ), the result is 14.7439928

Now, if I create a Windows Forms project, and use the built-in Math.Log10 function for the following function which is like the function above:

private float calc_ev(float lux, int iso)
        {
            // calculate EV using APEX method:
            // Ev = Av + Tv = Bv + Sv

            // We'll use the right-hand side for this operation

            // Bv = log2( B/NK )
            // Sv = log2( NSx )
            float Sv = (float)(Math.Log10((float)0.3 * iso) / Math.Log10(2));
            float Bv = (float)(Math.Log10((lux / (float)0.3 * (float)14) / Math.Log10(2)));

            return ((float)(Bv + Sv));
        }

With the Windows Forms app, the result for calc_ev(19.6F, 100) is 8.389544


Why are the results different? I expected the two results to be the same. I need an accurate Log value in .Net MF. The proper value is the 8.389544 value, so something wrong is happening in .Net MF. What am I doing wrong?

I guess it doesn't really have to be .Net. I've decided to use this for now: XML/SWF Charts

Hi, I have some values that I would like to graph. The x-axis will be Time, and the y-axis will be a sensor reading. My sensor readings are received every 1 second on the UART of a Netduino. Is there a graphing package out there that would fit nicely with the .Net Micro Framework? I would like to display the graph via a Windows form, or via a web page. Any suggestions?

Personally, I would choose X10 over PLC. --- EDIT: wow! that makes a LOT of sense. Not really.

However the transistors are connected to the 5v onboard power, so I expected the output to be at 5V rather than 3.3v is that correct?

I have confirmed the NetDuino is outputting 5v on the 5v onboard output and if I connect the relay directly it works fine.

Any ideas, have I misunderstood something?

Thanks,

Charlie M

I don't quite follow this. Are you connecting the transistors to the 3v3 or the 5v on the Netduino? The Netduino has outputs of 3.3vdc and 5vdc depending on which pin you use.

Also, what is the application with the kettles? When you say kettles, do you mean like teakettles for boiling water?

---> Edit, I think I follow now. Do you mean you are getting 3.3vdc from the I/O pins? That is what you will get. The I/O pins output 3.3v but are 5v tolerant. See the lower right corner of the spec sheet.


You will need to use the 5v supply pin to power your 5v device.

Oops, I didn't mean to double post! Sorry!

P.S., when it says that the I/O pins are 5v tolerant, it means you can connect a 5v signal input to the pins without damaging them.

However the transistors are connected to the 5v onboard power, so I expected the output to be at 5V rather than 3.3v is that correct?

I have confirmed the NetDuino is outputting 5v on the 5v onboard output and if I connect the relay directly it works fine.

Any ideas, have I misunderstood something?

Thanks,

Charlie M

I don't quite follow this. Are you connecting the transistors to the 3v3 or the 5v on the Netduino? The Netduino has outputs of 3.3vdc and 5vdc depending on which pin you use.

Also, what is the application with the kettles? When you say kettles, do you mean like teakettles for boiling water?