Thanks CW2!!

Hi! I bought a 3.7v 1000mAh single cell LiPo battery and a LiPo charger/boost converter (http://www.sparkfun.com/products/10300), but I don't understand how I can wire the LiPo battery to my Netduino Plus. Can I connect the LiPo battery to VIN and GND? Since I am only getting 5V from the battery, I don't think VIN and GND will work. Where do I plug in the battery to power my Netduino? Thanks! Nick

What is the best way to add Lithium batteries to a Netduino project? I need to be able to power the Netduino and connected devices via the Lithium battery and also recharge the Lithium battery via USB. I want it to all be self-contained, so that I will be able to simply plug a USB cable into the interface and charge the battery while also powering the Netduino and connected devices. What should I use?

I actually bought this the other day: http://www.sparkfun.com/products/10300, along with this cell: http://www.sparkfun.com/products/339. Do you know if the Power Cell - LiPo Charger/Booster will allow me to keep my project plugged in while also charging the lithium battery? I couldn't find a clear answer on that. I don't want to have to remove the battery and unplug my Netduino in order to charge it.

Looks like you can.

Chris- yes, this setup works great.

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 exclude a problem in my LAN because if I browse the ip of the router (192.168.0.1) from android, I have no problem. The strange thing is that from any other pc on my lan, all works fine... the problem is only from my android smartphone. Any suggest?

Just because you can browse the ip of the router does not mean that there is not a router configuration problem. Perhaps the router is blocking requests to port 80 or whatever TCP port you have configured for your web server. So if you go to http://192.168.0.1, all is fine because the Android phone is connected to the same router connection as your other computers (192.168.0.1 is probably the Default Gateway IP address) and the router is configured to allow local connections to its configuration pages. But if you go to http://192.168.0.7/relay_on, the router is internally blocking that request. I would check the port forwarding and firewall configuration of the router and make sure it is not blocking certain port requests from your Android phone. Some routers have internal log files that you can view to see if that is happening.

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).

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

I did try different baud rates. No luck. I also thought I saw in either the datasheet or the manual that you can use a PC to talk to it. I'm going straight from the serial port of my laptop to the module. I don't know what the voltage is, I will double check that. Tx and Rx are connected properly. What program to you use to transfer your AT commands?

Oops. You cannot connect directly from a PC serial port to the module. You will need to get 3.3V logic levels, and a standard serial port on a computer is not 3.3V. See how serial ports work. A USB-to-3.3V TTL converter works fine, and that is what I use.

Thanks, but I have tried sending the AT command several times. I even took the time to ohm out the pinouts from the breakout board back to the module and everything seems to be good. I think it's a baud rate issue, but since it's out of the box it should have the default settings. Do you know of a way to reset to factory defaults without using AT commands?

Webenglar,

Have you tried different baud rates to see if you can match with the module?
Are you using 3.3v levels?
Do you have tx on the module going to rx on the computer and rx on the computer going to tx on the module?


I apologize if these questions seem real basic, but just wanted to make sure.

I will check if there is a way to reset to factory default without the uart and will let you know shortly.

Thanks,
Nick

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.

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

Hi Nick,

I ordered a GainSpan module from SparkFun, and thanks to your code was up and running quickly. I haven't done any systematic measurements yet, but got the impression that the module's throughput is rather low.

I thought of using bulk mode transfers, which may be faster, but the documentation (Serial_to_WiFi_Adapter_Guide ver 5_3.pdf) appears inconsistent. I tried the command AT+BDATA=1 to enable bulk mode, and then ESC 'Z' for sending data, but got error messages. My module's firmware version is 2.2.4, btw.

Do you have experience regarding the module's throughput?

Thanks and best regards

Cuno

Hi Cuno,

I am glad to hear you were able to get the Gainspan module communicating. To enable bulk data mode, you need version 2.3.1 of the Gainspan firmware. To obtain version 2.3.1, you would need to sign an NDA with Gainspan for the firmware update. When you say the throughput is low, do you mean the Wi-Fi to serial conversion? You might try adjusting the Baud Rate of the serial connection. Please update me on how you're doing with it. Good luck.

Hi all,

The project files are attached. There are comments in the project indicating how to connect the Gainspan module to the Netduino. The code contains very little error handling, as this is currently in the experimental stage.

Here are links to the documents I consulted to put this together:

• Datasheet: http://dlnmh9ip6v2uc...eet ver 1.0.pdf
• Command Set: http://dlnmh9ip6v2uc...ide ver 5_3.pdf
• Sparkfun breakout board Schematic: http://dlnmh9ip6v2uc...reakout-v11.pdf

Yes, no problem. I will post the code in a few hours this weekend. I'll provide some details on how to connect it as well.

Hi, I re-factored the code today. There were issues with the DataReceived event and commands processed way too slowly. Now the commands are near-instantaneous to respond. This also adds the ability for multiple clients to control the LED, and I also added a small PC fan to the circuit, controllable via one of the PWM outputs on the Netduino Plus. The code update is attached.

Dumb question. Can this be used with a regular Netduino (not Plus)?

Yes, this can be used with the regular Netduino as well.

I bought a Netduino Plus but decided I really need to go wireless, so I picked up a Gainspan WiFi breakout board from Sparkfun (http://www.sparkfun.com/products/10505) and after some fiddling with the AT commands, I was able to get a WiFi connection going.

Hi all, For those interested, just an update on this Gainspan module- please note that in order to obtain the newest firmware and future updates, you will need to sign a mutual Non-Disclosure Agreement with Gainspan. I wasn't real happy about having to do this, but it was relatively painless and the new firmware opened up a world of more possibilities. It took me 8 days to get my NDA approved.

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.

For enclosures, I use small wooden jewelry boxes from my local arts and crafts store.