First off, let me say how glad we all are that your son is safely home again. Also welcome to the Netduino community.

Before proceeding it is extremely important to remember the difference between a hobby project and a safety critical device involving life or death. The "gold standard" for being found in an emergency is a EPIRB (and it's little brother, the Personal EPIRB, or PLB that fits in your pocket). These are extremely rugged, waterproof, tested to the highest standards and have long life batteries. Unfortunately one needs to press a button to activate them, so this is probably a "show stopper" for your application.

Another common device with a built in GPS and communication capability is a cellphone or smart phone. In an emergency authorities can easily locate a cellphone provided it is turned on and within range of a tower. It is highly unlikely that you can engineer a solution with similar capabilities at a lower cost than a used cellphone.

As far as a hobby project is concerned, you might want to consider fox hunting, where you simply attach a small transmitter to your son that sends a radio tone for a couple of seconds every minute or two. To locate the transmitter one only needs a simple receiver and a directional antenna. This is how biologists track animals in the wild. See http://www.predatorc...diotracking.htm for details. Newer versions often include a GPS as well. Here is a link where someone did it on the cheap http://www.thefintels.com/aer/frs.htm to find model rockets.

Finally there are commercially available pet tracking devices such as the Garmin Astro.

JonnyBoats,
Thanks for the insight. So I guess reading the moisture content of something physical is slightly more of a challenge than originally thought. And that's because i can't find a sensor that will do that for me... But really isn't it the same idea as a pentiometer? One prong receiving electricity, another for it to exit, and one in the middle to read what's moving across the other two?

Very similar. It you would like to try a simple experiment you could stick two pieces of metal with wires attached into a pot of dirt. Connect one to the ground on the Netwuino and the second to one of the analog input pins. This second wire should also be connected to a resistor (try 1 MegOhm, value not critical) and the other end of the resistor to +3.3v on the Netduino. This is what is known as a pull-up resistor.

If the soil is bone dry then you should read a voltage of 3.3v (give or take) on the input pin, this is because the input pin is connected to v+ via the resistors and the resistance between the two pieces of metal is essentially infinite.

Now pour some tap water into the pot. The resistance between the two pieces of metal will now become some finite value and the voltage on the input pin will decrease.

If you were to immerse the two pieces of metal into a glass of salt water the resistance should become very low and the voltage on the input pin become close to zero.

The only real problem at this point is that the resistance also depends on the distance between the two pieces of metal in the dirt. If you wiggle the wires anc change the distance the reading will change as well. A "real" probe will be made so that the two pieces are held at a small fixed distance and usually combined into what looks like a single probe. In fact one connection is simply above the other, just like on a headphone plug that you would plug into the audio jack on your PC.

You can now buy a commercial probe if you like, and as with everything else the price will vary depending on who makes it and the required degree of accuracy.

Currently I'm experimenting on a small scale using a window-box sized system. I'm in the process of building a greenhouse, and hope to automate it as much as possible, which is why I'm experimenting on the cheep now
For the full thing, I'll be building/buying sensors design for the long-term.

Thanks for the links! I actually have a pair or scrapped washing machines and a dishwasher, that I've been getting parts from as I need them. I'll see if I can find the sensor.

You might enjoy the video in this blog post: Plantduino Greenhouse Cares Of Your Plats While You’re Away In particular note how they use two ordinary nails to sense moisture in the ground.

All the details, parts list, schematic etc can be found at http://revoltlab.com/.

Could you get a 1/4 inch audio jack and just stick it into the soil?

last night I was trying to work out a probe that reads the water level in my hydroponic window box. because the feed water is slightly saline, it conducts, so this approach will work great for it.

In my case, I want to read 'full' or 'empty', so I will just have two wires that are stripped at the ends, just above the low level.

I had thought about using resistance wire, with the water level forming a potentiomiter. that would allow a measure of depth.

thanks for the info!

One thing that is not clear from your question is if you are just trying to experiment or learn or if you are looking for a robust solution.

The reason I bring this up is because measuring full and empty with two wires that are stripped is cheap and easy but does not have good long term reliability. The first issue is that when a DC current passes through the probes electrolysis occurs and the wires degrade over time. One can use better probes such as platnum electrodes and use an AC rather than DC current etc.

On the other hand one can purchase for about $5 a MEMS sensor such as is used in washing machines to detect water level which outputs an analog voltage proportional to the water level. They are extremely reliable and will last practically for ever. I have used the ones from Freescale (http://www.freescale...et/MPXV4006.pdf ) for just this purpose. Take a look at the MPxx4006 family.

Hello Mozsi and welcome to the wonderful world on Netduino!

I am not a Mac person, but I can tell you that having simple routines that allow reliable communication between a microcomputer and a desktop (e.g PC or Mac) is something that virtually everyone struggles with. The key hangup is reliability.

To be useful in the real world communication needs to be resilient; automatically recovering from such things as power failures, cables being unplugged and being plugged in again etc. If that is something you can workout it will be a great service to us all.

I don't know if this helps, but here is a project someone is doing for the Arduino: http://robotgrrl.com...no/matatino.php

Danny,

Do you have a volt meter or multimeter?

If so, you should measure the voltage present on your motherboard's pins. Most serial interfaces use 12 volts which is too much for a Netduino. Please be careful.

thank you both for your replies. i, too, believe that i will really enjoy using this thing once i get over this first bump.

i have considered buying another device for interfacing, but i seem to be predisposed to doing things the hard way.

on my motherboard there is a 'COM1' rectangular 10 pin (minus one) socket. 5 pins on top, 4 on bottom. like this:

http://vip.asus.com/...SLanguage=en-us
http://www.frontx.com/cpx102_2b.html

i experimented today with pins D0 and D1 on the shield base connected to (what i think are) pins 2 and 3 of this socket. i got some lights and strange characters to come up on the program http://realterm.sourceforge.net/

but i do not know what the pinout is, nor which pins need to be connected, nor how to confirm the connectivity.


once all of that is done, i am confident i can trudge through the rest on my own.


your help is appreciated.


danny

Hi dannykyle,

First off, welcome to the Netduino community. Once you get over your initial frustrations I believe you will have lots of fun learning with your Netduino.

If you find that your computer does not have a serial port connector, don't dispair. Their are other options.

In particular there are USB to serial converters that plug into a USB port on your computer. One thing to be careful of though is the voltage. "standard" serial uses 12 volts which is too high for a Netduino.

This cable might work for you as it uses Netduino compatible voltages: https://www.adafruit.com/products/70

Alternatively this might be even better: FTDI friend There is even a full tutorial on how to use it.

A power sub-station with voltages measured in kilovolts and 1000s of Amps is really a special case where safety is paramount. As suggested in another response only properly designed industrial equipment tested and certified for such an environment should be used.

For others who might be considering measuring voltages in a residential location such as 120V or 240V (still lethal) there is a good "general" model to follow.

A Netduino (or any other micro-controller) is generally designed to operate on 5V or less (3.3V in the case of a Netduino). It is not designed to survive the application of high voltages (think of it this way, if it would kill you, it will kill a Netduino).

The best approach is to keep the high voltage (or current) on a separate board from the Netduino,

There are many Digital Multi-Meters (DMMs) out there which will output their readings on a serial port. The DMMs are designed and tested to be safe and reliable for measuring voltages and currents within their design specification. You can connect such a DMM to a Netduino via the serial interface (you may or may not need a level shifter such as a MAX232 but that is another issue).

Here is a post where someone used a DMM from Radio Shack in conjunction with a computer: http://www.linuxtoys.org/dvm/dvm.html The price they paid for the DMM seems high (old post perhaps?), I know I bought one on sale (different model) for about $30.

For an audio device you most likely want a logarithmic rather than a liner taper. In looking through the data sheet (quickly), figure 2-2 (page 17) seems to show this as a linear taper.

OK, more digging... I found two good candidates, one 129-steps and one 256-steps digital potentiometer at 10kohm for good money.

I think these will work fine. Now how do I control a bunch (5-8) of these with Netduino, can I do that?

http://se.farnell.co...ip14/dp/9758615
http://se.farnell.co...-spi/dp/1578436


/Ken

Status update: the basic flashing routine for STM8S modules is working, at this moment in byte mode (*). Now, when the reflashing app for STM32 is available, it can be extended to include flashing of STM8S-based modules, so we can have an unified interface.

(*) Byte mode is the slowest, word and block programming are faster, but a little bit more complex.

Would you be willing to give a status update as well as information on how to get a copy of the flashing routine?

Thanks.

In another thread Chris stated: The modules should be flashable via go!bus, no special hardware required. And with the upcoming standard virtual I/O firmware, you'll be able to just say "use pins X, Y, and Z on the STM8S for the following features" and no knowledge of C or STM8S architecture will be required. Those pins/features will simply become "part" of the mainboard. WHat is the current status of this? I would like to flash a potentiometer module.

Take a look at http://videos.analog...elopment-Board/

You can get one for $30 here: http://www.analog.co...ts/product.html

This board runs on 2 AA batteries and logs the data to an SD card. After your workout session you could put the SD card into your Netduino Plus and do whatever with the data.

Tell us more about your sailboat,what kind, how big, do you liveon it etc.?

I have a LeComte NorthEast 38 sloop.

Many boats have expensive batteries,and monitoring them properly can make them last much longer and save a ton of money. Properly maintained (as in a data center) deep cycle batteries can last 10 years. Many boaters consider themselves lucky to get 3-4 years before replacing them.

If you want to do a really good job of battery monitoring consider using Kelvin 4-wire leads (http://en.wikipedia....erminal_sensing )

Curious if anyone has looked at the Raspberry Pi™ SBC? I've seen some talk about running NETMF on it, but don't know if anyone has taken the Linux compiled version of NETMF and tried it?

Sorry, I know this is not a NETDUINO related post, but I think there are some really smart and creative people on these forums... so what better place to ask.

I'm working on an audio project idea that I'm not sure could be accomplished with ND which is why I am looking at it.

I have been following the Raspberry PI with great interest. As you probably know, they are in extremely short supply and it will be a while (months) before most people can get their hands on one. Also the Raspberry PI has several features like USB host and HDMI video that would require drivers to work with NETMF. Since parts of the Raspberry By are not open source (particularly the Broadcomm chip used as the processor), I would expect the effort to develop drivers for all the hardware will be non-trivial.

In any case I am anxious to get mine, but to run Unix.

The design surface in Visual Studio for .Net Gadgeteer is very cool, particularly for documenting how the modules are connected. The code generation is of less interest to me for Netduino GO.

Here is a blog post showing how it works.

Has anyone given any thought to having this for Netduino GO?

There is one general trend that needs to be remembered, Moore's law. With virtually any computer, the one being announced and shipping next year will be faster and a better value than the one you bought last year. Comparing the Rasberry Pi to the Netduino is like comparing a PC to a Mac, the latest Mac is better than the original PC and the latest PC is better than the original Mac. If we think of a Netduino in general terms, that is a single board computer that runs the .Net MF, then surely there will be a newer version of the Netduino in the future with more memory, speed, I/O etc. Just think how great a Netduino with a couple of Gig of memory would be. You could fit the full .Net runtime in that! For me there are two key takeaways from all these single board computers: 1) They are advancing at a rapid rate with lots of newer, cheaper, more powerful ones coming out all the time. 2) These things are so cheap that it is easy to buy several to experiment and learn, there is no one perfect solution for everything. What a great time to be alive!

Hi,

i want to use my netduino code on an trinamic eval board. it has a AT91SAM7X256 instead of AT91SAM7X512

I believe your biggest problem would be that the AT91SAM7X256 has 256 Kbytes of flash wile the Netduino has 512K. I wouldn't say absolutely that it is impossible to get the .NET MF into 256K, but it would be a major challenge.

Far better to select a chip with adequate memory.

If you would like to see the .Net MF runnng on a M3 take a look at:

http://blogs.msdn.co...ce-project.aspx

I ordered and received one. As a watch goes, it is extremely thick and heavy. It definitely scores major geek points though :-)

Need a project (c#), in breadboard form to include the following:
2 Temperature/Humidity sensors.
1 RFID reader
1 Wifi
1 GPS
1-2 button(s)
1 display 16 x 2

We would all be glad to help you if you re-phrase your question, For example if you stated "I want to use a Netduino and would like to know what GPS, WiFi and Display shields work well with it?" I am sure you would get several well informed answers. As you probably know, shields simply plug into the Netduino (or Arduino for that matter) and generally are able to be stacked on upon another - no breadboard required.

Perhaps you are looking for a solution without any circuit boards? Did you mean you want to use a Netduino mini plugged directly into a breadboard along with other components? Your request is not clear.

Finally you do not state if this is intended as a "one off" project or a pre-production prototype. The reason I ask this is you should consider that there is already a readily available device that has:

RFID reader
Wifi
GPS
button
display

it is called a smartphone. All you would need to add is the two Temperature/Humidity sensors. Are you familiar with the Android Open Accessory Development Kit?

If you would like to discuss this further please send me a private message here on the forum and we can arrange to speak on the phone if you like.

Do you mean something like this? http://www.adafruit.com/products/601

Fabien Royer did a nice blog post on his Netduino-powered Game Console at http://fabienroyer.w...d-game-console/

Hello Avax,

Welcome to the Netduino forums.

In the past there has been some discussion of CANbus, but I don't know what the current state of that interface is for Netduino.

I do know there are several people (including myself) who would like to see it on the Netduino.

Hopefully others may provide more detailed information.

Hi everyone,

I am a total newbie here.

I have a project I am working on involving LIDAR. The laser measurement device supports CAN bus and I would like to communicate with it using CAN.

I like the netduino platform because I am an experienced .net developer and would like to stay in visual studio if possible.

Anyway I did a search here on "CAN" and nothing came up, but it very likely could be a filtered word like "the".

If anyone has any information on an existing project or thoughts on what hardware would be required to communicate on a CAN bus it would be appreciated.

Regards
Avax

I have been looking at Go module development and can see that another tool in people's toolset is a logic analyser would you say that this is he case?

With this in mind I was thinking of getting the sparkfun bus pirate as it's quite cheap. Would you say that this is a worthwhile purchase?

http://www.amazon.co...=A2UJ1UULX429TJ

Cheers,

Mike

Have you checked out http://dangerousprot...-pirate-manual/ ?

Keven is correct that a logic analyzer is a great tool, and will do more. That being said, the stuff from dangerous prototypes can't be beat for the money. $30 for the bus pirate is very cheap; of course you will probably want to buy some cables etc which will bring the price up some.

You may also like their logic sniffer - http://www.seeedstud...2.html?cPath=75 At $50 it too is very attractively priced.

You mean this one?

http://forums.netdui...4-game-console/

Yes, sorry. (It's still a great project though).