This may be a wild and crazy idea, but why can't the waste heat from the LEDs be used in some way to heat the water in the aquarium? It just seems really wasteful to be cooling the LEDs at the same time as one is running a heater in the water. Some PCs are water cooled, is there any way to have a water cooled LED mount?

I would like to start by building two modules: 1) A slide potentiometer first to get my feet wet. Circuit should be the same as the existing potentiometer module with a slider instead of a rotary control. 2) A rotary encoder module. Of course I have plans for more, but one needs to crawl before one walks or runs ;-) And I should add that both of these will be open source hardware and software.

Where can one find the bill of materials for the existing Secret Labs go modules? In particular I would like to know the manufacturer, part number and sourcing information for the socket. Thanks.

As part of this conversation, we should put together a workflow of best practices for building modules.

Chris

Absolutely! That would be great. Lets also have a workflow for prototyping modules.

Would it help if we bought a few thousand of each and bundled them in 10-packs for $9.95?

Chris

P.S. All of the PNs are in the .BRD design files.

What would be even better would be a couple of sockets and pre flashed STM8S bundled together for $4.95

With a new release of Fritzing (0.6.2) just released, I thought it would be a good time to bump this thread. I just downloaded the new release, and (like before) it is great to have all three variants of the Netduino in there "out of the box". A big thank you to those who made it possible.

I just did a blog post at: http://www.bitsconne...-crappy-surplus describing my experience whit the BOCS, including photos.



As a teaser, this is an image of what I added to the box.

For those of you following, I had no takers for a box opening party, but hopefully we can organize some Netduino Days at hackerspaces and other locations in the future.

The BOCS arrived in Maine! The box arrived here in Phillips, Maine yesterday. Is anyone interested in having a box opening party? I know Phillips is rather remote, so I am open to traveling to Portland, Bangor or Augusta ME to meetup with anyone who would like to share in the fun. I am even open to traveling to Portsmouth, NH if that is better for people. Please respond if you are interested. I do not want to hold the BOCS up too long, so we need to do thus soon if you are interested. Today is Tuesday, 4-OCT-2011. If nobody responds by tomorrow night, I will simply open it by myself and then send it along on Thursday.

The BOCS left Phillips, Maine (USA) today (Tuesday, 11-OCT-2011) on its way to David Stetz. The Post Office tells me it will take 2-3 days, so hopefully David will have it by Friday. I took photos and will post them here later today.

I am definitely interested and would like to participate :-) Would anyone else be interested in having "box opening parties"? My thought is that a bunch of us could get together at a house, hackerspace or restaurant and all open the box together. We would all bring stuff to swap as well and then put our extra stuff into the box before sending it on to it's next destination. Not only would this save on shipping, but would be lots more fun to share the excitement with others. It would be educational as well in that instead of simply taking something out of the box and wondering "what could this be", there is a good chance that someone else would recognize it and perhaps say "oh, that's a switch from the from panel of a DEC PDP 8 just like I used to work on in college". I am in Northwest Maine, and would welcome any Netduino fan to my house anytime if you want to come by and "play" Netduino. For the box however perhaps Portland, Maine or Portsmouth, NH would be a more convenient place for a Netduino fan club get-together?

Sneak peek inside the lab...

When we build new products, we usually spend about 6-9 months: design, parts sourcing, testing, building test jigs, etc.

To make Gadgeteer affordable, we needed to make our own plastic sockets for Gadgeteer accessories. [These sockets are drop-in replacements for the normal, more expensive sockets. You'll also be able to make your own boards and accessories...all open source.]

We just received the first batch of sockets, so I took a photo of a handful of them.

Now we'll do temperature testing (to make sure they survive the industrial reflow oven) and hand-assemble a few prototype boards.

BTW, a big thank you to the MSR team in Cambridge for their work on Gadgeteer (past, present and future).

Chris

Disclaimer: We haven't officially announced a Gadgeteer product lineup... We do sometimes cancel projects. But I thought I'd share a sneak peek update since you have shared your enthusiasm about Gadgeteer

Chris,

I was looking at the specifications for the connectors used by the .Net Gadgeteer and I see they are rated for an average life of only 500 insertions, which seems incredibly low.

What is the MTBF for your connectors?

We actually did a bunch of engineering on a SAM9G45-based open-source Gadgeteer mainboard. Basically, we offered to create a $99 open-source Gadgeteer mainboard, an open-source NETMF port for SAM9G45, and a bunch of open-source Gadgeteer accessories if MSR would open-source the Gadgeteer software. They worked hard on that and were able to open source the smaller core but unfortunately they didn't have the engineering resources to write all the Gadgeteer drivers.

So they felt that they needed to launch Gadgeteer with a closed-source partner. So we had to scrap a ridiculously awesome board.


Chris

Is/was your mainboard similar to this: http://www.armkits.c...CFdU55QodtTGCMw ?

You are quite correct that the hardware is quite capable of handling this frequency measurement task with ease.

The issue is the .Net Micro Framework. If you are willing to forgo .Net and program directly to the chip in C, you can get the job done.

What s not as simple or easy is to combine the use of .Net with native code and direct control of hardware interrupts etc. It may very well be possible, and I hope you succeed as we would all like this capability. You should be prepared for some setbacks along the way.

Can an Atmel AT91SAM7X512 microcontroller support the functions of the Taos TSL235R?

I am still not convinced that I need to throw more components at this problem. Netduino has an ARM7 48MHz processor- why should we deny that there is plenty of speed right on this development board? If I were to remove the processor from the Netduino and program it directly, or remove the .Net firmware and run C/C++ on it, I am sure that this sensor would run fine. I've read in these forums that version 4.1.2 of the Netduino firmware is supposed to offer run-time native code interop. I've also read about someone's project called "Fluent", which runs code something like 20 to 30 times faster than the managed code. I've also read that you can run FreeRTOS on the Netduino platform. Can't you run a quadrocopter with FreeRTOS? Isn't that real-time?

Does version Netduino 4.1.2 have runtime native code interop? If not, when will it have this functionality? Where can I get this "Fluent" project? Where can I find resources on how to run my own C/C++ on this board?

I understand the opinion that more tools will help me solve this problem, but I would rather use what I have instead of having to then deal with connecting, learning, and powering these other pieces.

Thanks,

Nick

As others have pointed out, a Netduino is not the right tool when you require precise real-time programming. There are however lots of cheap micro-controllers that can measure frequency and report the results to the Netduino via I2C or many other ways.

One cheap way to do this is with a TI MSP430 board which only costs $4.30 delivered (https://estore.ti.co...-kit-P2031.aspx ) This is probably the cheapest way to do a one-off project and the TI chip has reasonably good support.

The best way to look at this is that there is no one perfect single board computer. The key is to use one appropriate to the task and remember that they are cheap enough that you can break the task down and use more than one board.

Indirectly related, here is a blog post about the Beta of the NETMF port to the STM32 F4.

Additional information on NETMF for STM32.

I too find this sort of project fascinating. Thanks in advance for whatever details you choose to share with us.

Fabien, have you done a blog post or writeup on this? This is great information.

The detachable board on the STM8S has the necessary decoupling capacitors and features a 16 Mhz quartz for precision frequency counting / generation. Does the ProtoModule include a resonator or a quartz as well? For reference, here is the STM8S, detached from the STLink interface, with a Go! connector soldered to it:

This sounds like a marrage made in heaven Dan. Using the discovery board as a programmer for the proto module seems like a cheaper and more flexible solution rather than buying a separate programmer. Would you be willing to provide more details on your configuration?

I've attached an image of a bare PCB next to the discovery board. Note that the actual prototype area on the discovery is the parts below the routed slots. The part above those slots is the ST Link programmer, which is what I connect to the SWIM connector to program the chip on the protomodule.

I have somewhat of a mixed background in that I am a radio amateur (ham radio) as well as working as a programmer all my life.

In reading this thread (and lots more like it on other forums) I believe that often times people overlook that there is a big difference between knowing enough to get something to work and thoroughly understanding it.

Consider changing the oil in your car. That is something most people can do without an understanding of how an internal combustion engine works. By the same token there are some basics that one needs to know in order to do it safely and not ruin the engine. Things like "Shut the car off before crawling underneath to drain the oil" and 'Be sure to check the oil level on the dipstick before restarting the car and then check for leaks."

Now consider a simple electric lamp. One needs to have a power source, a lamp and some wire to connect them. One does not need to understand the difference between AC and DC current, or for that matter even care.

A good electrical engineer will understand Maxwell's equations, just as someone with a degree in computer science should thoroughly understand design patterns. That having been said, I know lots of people making a living as a programmer could not implement a state machine if their life depended on it.

The plain fact is that for _most_ of the things that beginners want to do with single board computers, knowledge of graduate level engineering is simply not required. What is helpful is the level of knowledge typically required to earn a boy (or girl) scout merit badge. Much of what one needs to know is best learned in a group environment with hands on labs. One could take EE courses at a university or one could simply go to a local hackerspace and learn by doing, benefiting from the experience and knowledge of others.

For those wanting an on-line resource to gain greater exposure to basic EE, two sites I have found helpful are the EEV blog and The Signal Path. If you are rusty on the math or other academic topics (like differential equations) the Khan Academy is a great resource.

Just keep in mind that learning electrical engineering and building simple projects are not always the same.

Finally allow me to say something to the EEs here. For a programmer who already knows C# (or VB) an .Net the Netduino is an ideal first single board computer. Why? because he already has the toolchain (Visual Studio) installed and running on his computer. While there are great, open source toolchains such as GNU on Unix available for a multitude of single board computers, for a programmer who uses Visual Studio on a daily basis that would simply be one more hurtle to getting started with micro-controllers. Similarly for a person with Unix PC who regularly programs in GCC, the Netduino may not be ideal.

Mention was made of the TI MSP430 which at a cost of $4.30 delivered has to be one best deals going. Personally if I am going to make a mistake and destroy a micro-controller I would rather make the mistake with one of my TI 430s than one of my Netduino Plus at $60. Heck, many places charge more that $4.30 just to ship a Netduino! The point being that there are lots of boards and parts available and it is usually best to try many of them and learn rather than fret over finding the one best one.

Have you considered measuring magnetic field?

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.

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

Here is a post you may find helpful: http://www.faludi.co...sensor-circuit/

Basically the way it works is that the resistance of wet soil is lower than that of dry soil. You could either make your own probe or hack one of the cheap probes from a garden supply shop.

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.

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.