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#33557 Barcode Scanner and Netduino.

Posted by Dan Morphis on 13 August 2012 - 11:44 PM in Netduino Plus 2 (and Netduino Plus 1)

Thanks Chris.
I happen to have a USB one, but it seems a much more complicated affair to get that working without a USB Host shield.
I'll probably rather get an RS 232 one.
Thanks for your input.


If you open up the device, I bet you'll find a TTL serial->USB converter chip. You could hack it and pull the data right from device before it goes into the chip. The two most common serial->usb chips are the PL2303 and FT232.

Doing that will keep you from having to buy another barcode scanner.

-dan



#33173 Why choose Netduino over Arduino?

Posted by Dan Morphis on 06 August 2012 - 06:30 PM in General Discussion

I discovered the Netduino a couple of days ago!
I have recently started development of internet-connected devices using the Arduino Uno and an Internet shield.
I am intriguded by the power of C#, multithreading, debug and the many other features of Netduino that make it easy and fast to develop internet-connected devices.
There are, however some drawbacks: limited product range, limited supported devices and related code, limited competition (price), limited support (just this forum?), fewer sample code available, ...

You have the experience, so help me make an informed decision:
1) Based on your experience, what are the 5 key reasons why Netduino is a better development tool for developping custom internet devices that Arduino

2) How do you deal with the restrictions/drawbacks compared to Arduino to reduce their importance


One of the big reasons for me why I use the NetMF platform using Netduino over Arduino is debugging. With Arduino, without going through a lot of gyrations, you have two basic ways of debugging. Serial.println, and flashing an LED. Serial.println works fine if you don't need to use the serial port(s) for other purposes.

With NetMF, you can do Debug.Print (or is it Console.WriteLine - don't my code in front of me), write out to a serial device, twiddle an LED, and most importantly, single step through the code to inspect what is actually going on. Another big thing is the code that you write, is the code that gets uploaded to the board.

With Arduino, if you use the Processing language and Arduino IDE, what you write is not what gets compiled and uploaded. A good example of this is some code I wrote last week, one of my preprocessor directives was wrong. The output from GCC which the Arduino IDE spit out said there was an error on line 133. My code didn't have a line 133. So I had to turn on verbose compiler output, so I could see where the actual file that the Arduino IDE was feeding to GCC was. Then open that file up and see what the actual error was.

That said, both platforms have their strengths and weaknesses.

Another big one is interrupts. Only pins D2 & D3 (IIRC) can be used to trigger interrupts. On the Netduino, any pin can trigger an interrupt. Interrupts are useful to have the microprocessor tell you when something has happened, instead of having to constantly monitor the state of a pin, and do your own checking on if the state of the pin has changed, and if that state is one you care about. For example, you can trigger when a pin goes high, goes low, or both.

-dan



#31015 4 Digit Seven Segment LED Displays.

Posted by Dan Morphis on 21 June 2012 - 02:05 PM in General Discussion

I'm not very good at this yet, so, I was hoping that someone might be able to point me in the proper direction.

I have an application where I would like to use 2, 4 digit seven segment displays. The P/N's are BL 056C 4343UHR-11. I will be using a Netduino or a Netduino Plus (I have both). There are 14 pins on each set of 4 digits displays. I think that what I need is something like Adafruit's LCD backpack, but for LED's. I can also use some LED IC's; or, I am going to have to use a Go and gang the shields; but, I am looking for something a little more elegant (not to mention portability is a concern).

I would like to know is there is a backpack analog for LED's.

In earlier posts, there was a mention of a "SandBox". The link went nowhere. Is there a "SandBox"?


I'm not aware of a "backpack" for 7 segment LED displays. But you can easily use a shift register to drive the displays. This will cost you 3 pins on the Netduino, but gains you a virtually limitless number of pins. You can either use 4 8 bit shift registers like the ever popular 74xx595, or two 16 bit shift registers like the 74xx676. They do have 32 bit shift registers, but I can only seem to find them in surface mount.

-dan



#30381 Oscilloscope

Posted by Dan Morphis on 07 June 2012 - 07:32 PM in General Discussion

Just as an update, while looking for a recommendation on which Ocilloscope to buy I came across this thread, the RIGOL DS1052E was mentioned as a good scope (I am sure that it still is).

While this model can still be found for sale I found that it has been replaced by the RIGOL DS1102E for the same price range as the older model (was $795.00 now $399.00) and has a 100mhz bandwidth. RIGOL DS1102E


The DS1102E doesn't replace the DS1052E. The DS1102E is a same board, chips, components, etc as the DS1052E, except it has a different label on it, and bit has been twiddled in the firmware to allow capture at 100 MHz. As @nakchak mentioned, with putty (or any other serial terminal program) and some very easy instructions on the net you can turn your DS1052E into a DS1102E.

-dan



#30050 I'm New

Posted by Dan Morphis on 31 May 2012 - 06:53 PM in General Discussion

Hello to all, I am new to the Netduino board programming and I would like some help or advise on getting started and creating cool projects.

all help and advise is greatly appreciated!


Welcome to the community!
What kind of issues are you having? What kinds of things would you like help on?

-dan



#28685 CAD Software and Board Manufacturer Recommendations

Posted by Dan Morphis on 08 May 2012 - 06:57 PM in General Discussion

Have you stumbled upon any scripts to import eagle schematics? I searched Google a bit and didn't find anything.


I don't know how KiCAD does it, but other programs I've experimented with require you to open your schematic and board in EagleCAD, then run a ulp (user language program) they have written to export the data into their pre-defined interchange format.

-dan



#28684 CAD Software and Board Manufacturer Recommendations

Posted by Dan Morphis on 08 May 2012 - 06:54 PM in General Discussion

Since I took a break from Electrical Engineering in 1997 to pursue other career aspirations, I am sure Electronic CAD and Board Manufacturers have changed a lot.

As I begin the next phase of my project, building a Bill of Material, then laying out the board (shield) and sensor boards... I figured it was time to get some recommendations from the members as far as which CAD software to go with. Not looking to spend an arm and a leg on it. Also, are there an board manufacturers that people have used that are particularly good and maybe support small quantity runs?

NOTE: I have both a MAC and a PC so the CAD's OS is not a deal breaker. I also like the look of the black masked Netduino boards. This would be a preference when it comes to the board maker.

Thanks in advance for any advice.


Depending on how big your board is, if you need cheap proto boards, itead studios can do 10 5cm*5cm two layer board for $9.90.

-dan



#26880 Cannot find any entrypoint!

Posted by Dan Morphis on 10 April 2012 - 05:12 PM in Netduino Plus 2 (and Netduino Plus 1)

I'll try that when I get back home, what I did already try was a full erase, reload tinybootloader, RC4 and I got the same issue. If VS states "Assemblies successfully deployed to device." does it really mean it?


You don't by chance have multiple projects loaded in your solution do you? If you have multiple projects in a solution, everyone of them gets deployed to your board, and then its luck of the draw as to which one actually gets executed.

-dan



#26787 How to drive train models

Posted by Dan Morphis on 09 April 2012 - 04:40 PM in General Discussion

Thanks for the offer of a free dinner and well done on the research!

Threads will always have people that disagree. There are some basic recommendations in the thread you found:

  • use a slow clock speed, the SPI interface becomes more reliable when you slow down the clock,
  • use filters to try and remove high frequency noise,
  • use logic chips to clean up the signals before they go to the next device,
  • use cables that have shielding (a metal screen around the outside of the cable).
I think all of these things will help, but the railway may still have too much electrical noise for the system to work reliably.
If you have the time and some parts you might try it out with one or two shift registers to see if it can work on your railway. I'm sure there would be lots of interest in your results on the forum.

The Texas Instruments note goes into detail on what the problems are.
They end up suggesting using some transceiver chips (SN65C1167) that are used for RS422/RS485 interfaces. This will cost more to implement, but it will be more reliable and may make the system work.

Regards - Paul


What about breaking the problem down into discreet components, all orchestrated by a master controller? This will require a little bit more on the cost side, but should allow for better expand-ability.

So the issue as I understand it is how to reliabely get a single over a longish distance? The a complete RF transceiver module with the NRF24L01+ chip can be had for $2.32 on eBay. Use that as the communication link between modules. And use a Netduino Mini at each point to do the comm and handle turning on the LEDs, etc.

Just a thought.

-dan



#26658 Interfacing with home heating system

Posted by Dan Morphis on 06 April 2012 - 09:17 PM in General Discussion

Hi Dan,

You could use an opto-coupler. Take the 24V AC put it through a resistor and then into the LED of the opto-coupler. Connect the transistor of the opto-coupler between a Netduino pin and ground. Configure the Netduino pin as an input with internal pullup resistor.

When the t-stat calls for heat the LED will pulse the transistor ON, and the input will pulse low.

There is a slight problem - the input will be pulsing at the same frequency as the AC. This might cause issues in the software.
If it does, you could use a bridge rectifier and capacitor to turn the AC to DC before it goes into the LED.

No moving parts - except the electrons and photons!

Hope this helps - Paul



Thank you Paul! I hadn't even considered using an optoisolator!

-dan



#26645 Interfacing with home heating system

Posted by Dan Morphis on 06 April 2012 - 05:40 PM in General Discussion

So after buying a second ThermoDisc in as many years I've decided to replace it with something solid state.

Some background
A thermodisc functions as a time-delayed relay. When your thermostat calls for heat it bridges two wires together completing a circuit. When that circuit completes, a heating element in the thermodisc heats up, causing a little disk (the disc part of thermodisc) to change shape which causes the disk to push a little pin closing a contact which then causes the circulation fan to turn on. When the thermostat is done, the circuit opens, and the thermodisc cools down, and disengages the fan.

While this works, its wildly inefficient. The relay engages 20-30 seconds after the burners fire, and disengages 20-30 seconds after the burners turn off. My goal is to use either an IR temperature sensor, or a high-temp thermocouple to read the temperature of the heated surface and use that to turn on/off the fan.

None of that should be to difficult (I hope). My question is this though, what is the best way of interfacing to the existing system to get notified when the t-stat calls for heat. The wires put out 24v AC when the t-stat calls for heat. My first thought was to wire that into a relay that would then pull a pin high. But I would like to eliminate as many mechanical pieces as possible.

Does anyone else have another idea?

-dan



#26021 Client Socket + serial number pad

Posted by Dan Morphis on 27 March 2012 - 04:50 PM in Netduino Plus 2 (and Netduino Plus 1)

Hi Everybody,

This is my very first post or question.

We have a project where the employees will use a barcode reader (serial rs232) and a number pad (serial rs232) to check the employee number and a number that defines the number of operations they make every certain time.
After that is made we want to use a client server connection where the netduino will play as client to send that information to a server.

I am struggling with the socket part because I an not able to find some code about it, could you guys give a hand?
Regards


Francisco, welcome to the Netduino community!

There has been a lot of good sample socket code posted to the forums. I would search for socket, or webserver. This sample code is a webserver, it primarily shows how to accept incoming connections on the Netduino, but you should be able to adapt the code to your needs.

Another project to look at is Home Automation with Netduino and Kinect (source)

-dan



#25990 PWM Input from the ground up

Posted by Dan Morphis on 26 March 2012 - 04:39 PM in Netduino 2 (and Netduino 1)


What I want to do with Netduino, is plug my Futaba Receiver's digital channels one to four into Netduino as inputs, and then read the pwm values in my C# code, interpret that, and then control things with it.


Anthony, although it would require a change in xmitter and receiver, have you looked at the Spektrum stuff? Their receiver spits out straight 115,200 serial with all the channel values. A good friend is using those with an Arduino to build a product for the R/C world.

Just a thought, although I know buying a new transmitter and receivers is a spendy proposition.

-dan



#25633 Detecting Sensor Type

Posted by Dan Morphis on 16 March 2012 - 05:24 PM in Netduino Plus 2 (and Netduino Plus 1)

I've been theoretically working on this for my project but haven't put it into practical use, but it won't work exactly the way you are thinking.

I have a number of sensors built into my project but there are 3 sensors that I have not added in, because I want them to be add-ons where someone can plug an external box in that contains 1 of these 3 sensors. In my case all 3 sensors are I2C.

The scenario I have on paper is to try and initialize these sensors one by one. If the Initialization sequence fails (basically it is not found on the address) then it sets a flag so the code doesn't try to get readings from those sensors.

But, as I said, it is theoretical right now and will only detect the fact that these 3 specific sensors are or are not connect.


Dave,
One wire has the ability to do pseudo discovery in that each device has a unique 64 bit serial number burned in at the factory. I haven't had a chance to look at the specs to see if there is a numbering convention one could use to do discovery of the actual type of the device.

-dan



#25632 Detecting Sensor Type

Posted by Dan Morphis on 16 March 2012 - 05:19 PM in Netduino Plus 2 (and Netduino Plus 1)


Usb devices do have a discovery mechanism but I am fairly sure the Netduino usb connector cant be configured as a usb host anyway.


Magpie,
IIRC, in the latest 4.2 beta firmware, Chris and company have added basic USB host support. I believe they have a keyboard working?

-dan



#25631 Webserver with Login

Posted by Dan Morphis on 16 March 2012 - 05:16 PM in Netduino Plus 2 (and Netduino Plus 1)

Hi,
Someone has some advise on how make some pages on netduino webserver protected by login?
Is possible to use browser session?

Thanks


As far as I'm aware, the webserver implementations for the Netduino do not support HTTP Authentication. It would be fairly trivial to add support for basic HTTP authentication. But be aware that the credentials for basic auth are encoded, NOT encrypted.

-dan



#25415 Can PWM interfere with I2C?

Posted by Dan Morphis on 12 March 2012 - 05:34 PM in Netduino Plus 2 (and Netduino Plus 1)

Hi everyone,

I did a bit of rewiring, replacing alot of 12" jumper wires with shorter length breadboard jumper wires. This seems to have gotten things working well enough. Magpie I didn't end up trying different frequencies for the pwm or I2C but I'll keep that in mind if it comes up again. Thanks for the advice Dan, I hope I won't have to resort to a Faraday cage for this project but who knows. It would be nice if you could buy some shielded cable sheaths though, has anyone seen anything like that?

thanks


Buying shielded cable will probably run you a pretty penny. A much cheaper option is get some RG-6 (coax), and carefully strip off the outer plastic shield, then pull out the inner solid-core wire and plastic tube. So what your left with is a braided tube of copper wire. I have used that in the past to make cheap DIY shielded cables.

-dan



#25414 CT Sensor help please!

Posted by Dan Morphis on 12 March 2012 - 04:37 PM in General Discussion

I want to use it to monitor the operation of a 220V pump. I don't need to get any sort of accuracy, I just want to be able to sense when the pump is powered on and when it is off.


This might be to simplistic for your needs, but what about mounting a reed switch next to the motor? It should trip when the motor engages.

-dan



#25158 Netduino Plus not detecting

Posted by Dan Morphis on 06 March 2012 - 08:56 PM in Netduino Plus 2 (and Netduino Plus 1)

Hi Kiran,

Glad that you're up and running! *whew* :)

If you're powering your Netduino via USB or the power barrel, then the 5V pin on your Netduino should provide a 5V source for your circuit.

Please note that USB power is "roughly" 5V and could vary from 4.5V-5.5V in range. But it's close :) If you need a regulated steady 5V, then plug in your Netduino using a DC power adapter.

Chris


To add to what Chris has said, do NOT plug your board into both USB and power it via the barrel jack. Its an either or situation, unless you want bad things to happen IIRC.

-dan



#25157 Can PWM interfere with I2C?

Posted by Dan Morphis on 06 March 2012 - 08:54 PM in Netduino Plus 2 (and Netduino Plus 1)

Hi Magpie,

Following up on your advice, I read a bit about voltage changes induced by high current wires that aren't even part of the same circuit and one of the things they suggested was to coil/twist the high current wires around each other. I tried this (and also moved them marginally further away from the rest of the circuit) and immediately there was a difference. The gyro didn't lock up the first time but ended up reading wacky values progressively. The 2nd time it locked up still but it got alot further than usual. So it would seem to be almost definitely induced interference. I didn't have any 0.1uF capacitors to run across the motor terminals which they suggested as well. The combination of twisting the wires and keeping them further away and the caps hopefully will be enough to allow me to get this working. If not maybe I'll have to get some low current motors instead.

thanks


Is there anyway you can shield things? Either by putting a shield around your control boards, or around your motors. A cheap and easy way is a Faraday cage. You can build one pretty easily with some aluminum mesh from the hardware store. Look in the window screen section. Be warned, its a real pain to work with, and you will need to have something like tin snips to cut it.

If you fully enclose either your motors or driver boards, you should see your interference go away.

-dan



#24935 RFID reading

Posted by Dan Morphis on 01 March 2012 - 10:45 PM in General Discussion

There's a series of model kits that are coming out with RFID chips (circuits) imbedded in parts that connect it to a game.
As the Japanese hardware is not available in the UK (and probubly never will) how do I go about getting a pc based solution to this problems.


The first thing you have to identify is what freq does the RFID chip work at? A lot of your proximity cards are either 125 kHz or 13.56 MHz. If the tags your trying to read work at either of those frequencies, then you are probably in luck. The next thing you need to figure out is what is stored on the RFID chips? Is it a simple 16 byte chunk of data? Or is it a 1k block? How does the particular RFID chip encode the data?

Once you figure those things out, you can more than likely find an off-the-shelf chip to read the RFID chip. Then its a simple matter of buying the chip and either wiring it up to a Netduino/Arduino to do any processing that maybe needed, or outputing it to serial and reading it on your PC via a serial->usb converter. All the RFID chips I've dealt with output straight serial.

-dan



#24620 Powering the Netduino

Posted by Dan Morphis on 23 February 2012 - 06:53 PM in General Discussion

Why? Well, couple thoughts come to mind:
1) Not really sure what I'm doing :)
2) I was working with what I had and then tried to add in pieces to that. Something else to remember - my first regulator is also converting AC -> DC, not just dropping the voltage.

So that 5V can function either as a 5V out or a 5V in?

Would someone mind also clarifying one of my earlier statements about how to properly add up the power usage of the various components (which are running at different voltages)?

At first I was just adding up the mA, regardless of voltage. But then it occurred to me that it probably doesn't work that way. It seemed to make more sense that I should convert any particular value (such as the 60mA @ 3.3V for the LCD) to VA. I can then add up VA to make sure I don't end up accidentally exceeding the rated value of the AC->DC converter.

I suspect given that the LCD turned out to be much smaller than I initially understood that this won't actually matter - but I would like to know the proper way to calculate that for the future.

Thanks


Yeah, it can function as a 5v in, there is no diode on it. So, keep that in mind and be very careful not to swap the positive and negative rails.

The easiest way to figure out your entire load would be to convert your power usage to watts, Watts = Volts * Amps. 1 amp at 5 volts is the same power usage as 0.5 amps at 10 volts. So if you do your calculations purely on the amps used, you would be off.

So for that LCD, which consumes 60mA at 3v3 you have W = .06 * 3v3, or .2 watts, which is a negligible amount of power. For the relay board, you have W = .5A * 5v or 2.5 watts. And the Netduino is W = .2A * 5v, or 1 watt. So total we are looking at 3.7 watts.

Now to take that and figure out how many amps at 5 volts you need. 3.7W = A * 5v, 3.7W / 5v = A, A = .74. So to power what your looking to power, you would need a 5 volt, 740mA power supply. Now, that number doesn't account for any losses that occur with the 3v3 regulator, and it gives you no head room.

So if it was me, I would use a 5v, 1A regulated power supply.

As to your comment about your first regulator doing AC -> DC, you can easily convert AC -> DC by using a bridge rectifier. You can make one yourself with with 4 silicon diodes like the venerable 1N4004, or you can buy one pre-built in a package for < $1.

-dan



#24565 Powering the Netduino

Posted by Dan Morphis on 22 February 2012 - 06:36 PM in General Discussion

My intent was to get something like this DC stepdown. Split the 12VDC before it goes into the Netduino and run it through this to step it down to 3.3V.


Why buck it down to then run it through a linear regulator? Very inefficient, and the linear regulator will be running quite warm. I would buck it down to 5v, and then put the power into the Netduino via the 5v pin on the header. Then for your 3.3v needs, you could linear regulate it down to 3.3v with a LD1117. You wouldn't be eating up nearly as much power to regulate 5v down to a 3v3, vs 12v regulated down to 5v (which the Netduino does when you feed it via the barrel connector).

-dan



#24189 My Netduino CNC Machine

Posted by Dan Morphis on 13 February 2012 - 07:20 PM in Project Showcase

Yes I'm using a computer power supply and it works great. If you need more power you may want to consider something bigger.


You can buy an HP DPS-600PB server power supply off ebay for around $15 which will supply almost 50 amps. It will require some modding to add the terminal posts though. I use it to drive the spindle for my CNC.

If your looking for a fully assembled solution that will provide just shy of a 100 amps, a very good friend of mine sells a fully converted HP DPS-600PB (x2) for $47. His target market is R/C where they use them to drive their battery chargers. I've seen the kits in person, and he uses really high quality components, no 16 AWG wire :-)

If your not interested in buy his kit, get some *good* 30 amp binding posts. You can use the kit details for a parts list if need be.

BTW, I don't get a cut of the proceeds, just recommending them because they are HQ!

-dan



#23863 Resistors

Posted by Dan Morphis on 06 February 2012 - 06:37 PM in General Discussion

Hard to tell how much people are color blind. Only males are affected.


Not 100% true, females can be affected by color blindness as well, but the rates are much lower. 8% for men, and 0.5% for women - Color blindness




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