Thank you so much! Yes, I will have an eye on the creepage distances. We thought about normal resistors because we found relatively expensive HV resistors. But as I saw in your link this must not be the case and so we will use HV resistors and not count on cheap SMD out of spec! A worth-full hint!

Yes, correct: Replacing the circuit 5x and run it with 5 different PWM pins. I have not planed the voltage divider as feedback because we do not need it--besides you will recommend it as fallback safety component ...

Wow, what a fast reply! There is no reason not to use your schematic, as in some projects first you think about a solution and after a time (and some work is done) you find a better solution in the web ... ;-) So, thanks a lot!

We thought also about increasing the total bleeder resistor value. Thanks for the link to the 22M resistors, 20uA @5kV would be great. I think I have to test how fast discharging will be. We like to use SMD resistors to save space, hope there is no downside compared to normal bigger resistors regarding HV.

Ok 15V supply for the circuit. I have planed to power the Arduino, up to 5 "GP 50 HV" modules and a radar sensor (8...15V, 30 mA) with one supply. I think this is possible even if the Arduino is recommended up to 12V.

I have "beautified" your schematic and added the voltage divider. Hope that are right, R1 and R2 are not according to your direction in the post, but swapped. Please check if this is so correct in the attached schematic.

Many thanks and Karma++

Thanks for your answer! First of all the Emco GP 50 HV modules we are using are a kind of DC-(HV)DC converter (see http://hivolt.de/index.php?id=gp_series). From the datasheet: "The isolated output is proportional to the input, and is linear ..."

But the problem is
1) that I do not have a real "analog" signal as input. It is only a PWM signal that I have to smooth. With direct PWM the Emco modules do not work properly
2) that I have--via PWM-- only up to 5V and the Arduino current but I need for the GP 50 HV modules up to 12V and 150mA to drive the modules

Do the DC-DC converter your mentioned also the demodulation / smoothing of the signal when input is PWM? What "specialist chip" do you have in mind?

I thought about using the Arduino Due, to have a real analog signal, but the Due has only 2 analog out pins (we need 5) and it's still only up to 3.3V so not much is won ... I think I can smooth the PWM signal with an low pass

If I got you right the Low Pass an the 12V level waste power. So the smoothing should be done before amplifying the 5V Arduino signal to 12V, right? I found this schematic http://arduino.cc/forum/index.php?action=dlattach;topic=153684.0;attach=38804;image in the old thread http://arduino.cc/forum/index.php/topic,153684.msg1163154.html#msg1163154 is this a good way to go? Get rid of the MosFETs, smmothing the signal direct after Arduino out, using a LM358 as OP and ... hmm what do I have to change that it will work with my GP 50 module? Is the BD435 and BC337 still ok? I think I have to change the Zener diode to 12V ... I do not really understand what the two NPN and resistors after the OP do?

There is an--unfortunately closed--thread under http://arduino.cc/forum/index.php/topic,153684.0.html I like to continue here.

I have a similar problem, I like to drive up to 5 Emco GP 50 module (out 0-5kV, 200μA; in: 0-12V, <150mA) http://hivolt.de/index.php?id=gp_series with an Arduino for an art project.

My initial plan was to use 5 PWM pins and drive some IRLU2905 MosFETs (recommended by an electronics engineer) wiring appropriate to the schematic under http://bildr.org/2012/03/rfp30n06le-arduino/. The engineer added a 1KOhm resistor between Arduino pin and gate. It should be possible to drive Arduino and HV modules over a single source and branch off the 12V for the HV modules over Vin http://arduino.cc/forum/index.php/topic,161810.0.html

My problem is now: How to smooth the output of the MosFETs? Can I simply add a low pass filter as described her: http://provideyourown.com/2011/analogwrite-convert-pwm-to-voltage/ (further down the page). Or is the MosFET approach completely wrong and it is better to use an OpAmp?

The next problem: The GP 50 do not have "internal bleeder resistors on the output. Provisions must be made externally to discharge the output capacitors if this feature is desired" the datasheet says. Special HV resistors are expensive, our idea was to add about 10 normal 1-5MOhm resistors in series to have a "bleeder resistors". Unfortunately this eats lot of current. It is about 1/3 higher than without it. Any idea how to manage this? 

I made some tests with QRE1113 sensors and I do not think that this will work for your requirements. You can try to use the sensor as analog device but the initial design goal was a kinde on / off switch.

If the backing film is more or less transparent you may try a fork light barrier. Even when a standard version is not working you can try to use a really bright LED on one side of the label rolls and an normal light sensor on the other side.

There are also Sharp distance sensors out that are designed to detect if a sheet of paper is feed in. They measure the thickness of a paper. This is also what you need. but I think 50 per second is really fast, and the fast moving process will also cause a jitter of the roll. You may try this one http://www.produktinfo.conrad.com/datenblaetter/175000-199999/185366-da-01-de-PRAEZISIONSSENSOR_GP2Y0AH01K0F.pdf 4.5 - 6 mm (0.1 mm resolution) but search it there is one out with a higher resolution that I oversaw.

There is a old, read-only post about the Sharp IR sensor GP2Y0A710K0F, this is the big one with a range of 100 - 550 cm
http://arduino.cc/forum/index.php/topic,11000.0.html

In the Datasheet http://www.produktinfo.conrad.com/datenblaetter/500000-524999/504597-da-01-en-DISTANZ_SENSOR_GP2Y0A710K0F.pdf you can read

Please use a power suply which can output 350mA or more to operate this product properly since this product requires about 330mA as the sensing peak current to LED.

So I think I can _not_ use the sensor with an Arduino Uno, who has (s. http://playground.arduino.cc/Main/ArduinoPinCurrentLimitations) a max of
DC Current VCC and GND Pins...... 200.0 mA

How did you run this device? With an OP and the Arduino as source? With an external source? I think takeing it from Vin is not possible because the spar sensor runs best @5V and the Arduino needs an Input Voltage over 7V. Is 6V a compromise that runs? Or do you see any major disadvantages?

Ja, könnte man sicher mit einem Y-Kabel machen, das (die 12V-Quelle) würde ich aber auch nur mittels Schraubklemmen auf das Arduino-Shield leiten, um es dann per MosFET oder wie auch immer weiterzuverarbeiten, wenn der Vin aber genau das gleiche macht, ohne zusätzliche Buchse, ohne Y-Kabel usw. dann würde ich mir den Zusatzaufwand gerne sparen.

Die Empfindlichkeit in direkter Richtung passt ganz gut, das Radarmodul soll (über den Arduino) die HV-Module anschalten, wenn jemand in die Nähe des Kunstwerks kommt, ich hoffe der minimale Abstand von 4m aus dem Datenblatt reicht aus.

Hat noch jemand einen Link zur Auswahl bzw. Vor-/Nachteile von Transistor vs. MosFET vs. OP? Was würdet ihr da verwenden, wenn der Arduino 0 bis 12V über PWM erzeugen soll. PWM haben wir mit dem HV-Modulen getestet, allerdings mit einigen Bauteilen dazwischen um etwas zu glätten. Allerdings war dann die Reaktionsgeschwindigkeit recht gering, weshalb wir da nochmal ran müssen.

The features are not hardware related. Any GSM Shield got the same hardware components so there should be a way to get the lib running.

I would this expect too, because the functions based upon AT commands--as I know. Is this right or are there any hardware related things in the new lib? So the difference can be pins or some on / off trigger. I started a discussion respective "internet connection" on
http://arduino.cc/forum/index.php/topic,157209.0.html I'm a bit stuck but the "generate turn on pulse" seems to be necessary in addition to the code from the new lib. But I could not manage to insert this code on the right position. Perhaps you can have a look at this.

@t3d_et: Wenn ich das richtig verstanden habe läuft der Vin eben nicht über den Spanungswandler! Sind die Leiterbahnen so schwach dimensioniert, dass sie 1,5A nicht abkönnen?

@mkl0815: Ja, mann könnte die direkt an der Platinenunterseite abgreifen. Praktischer wäre es aber sie direkt am Vin auf ein shield zu bekommen, wenn, ja wenn das eh nur durchgeschleift wird. Da ist aber wohl noch eine Diode dazwischen (s. Link im nächsten Absatz):

Habe hier noch etwas dazu in Erfahrung bringen können, 1A über den Vin geschleift sollte auf jeden Fall gehen:
http://arduino.cc/forum/index.php/topic,161810.0.html - ggf. geht auch noch etwas mehr.

Ja, OP oder MosFET ist sicher richtig, für die HV-Module! Das Radar-Modul hat einen Open Kollektor-Ausgang: http://www.produktinfo.conrad.com/datenblaetter/500000-524999/502667-da-01-de-RADAR_MODUL_RAD_MOD.pdf wenn ich das richtig verstanden habe, kann ich den Ausgang einfach mit einem 10K pullup (der Arduino-Interne 20K sollte auch gehen, oder ist da was zu bedenken bei einem Open Kollektor?) an einen digitalen pin anschließen und das Modul an sich mit 12V und gemeinsamem GND betreiben.

Was mache ich denn mit den HV-Modulen? http://hivolt.de/index.php?id=g_series. Den Eingangsstrom (bis 12V, <300mA vielleicht mit einem anderen Modell auch <150mA pro Modul)  könnte ich auch vom Vin abnehmen und dann mit einem MosFET wie z.B. hier http://bildr.org/2012/03/rfp30n06le-arduino/ oder einem Transistor http://bildr.org/2011/03/high-power-control-with-arduino-and-tip120/schalten, die Module muss ich über PWM ansteuern. Welchen FET würdet ihr denn empfehlen? Was wären die Vor- bzw. Nachteile zu Transistor vs. MosFET vs. OP, weitere Alternativen, die ich bedenken sollte?

Thanks a lot for your answer and the elaborated alternatives to handle high current. I will try the "as is" approach and will measure my real current. 1.5 A is at paper so I think it will be worth a try. ;-)

There is an old (read only) thread from 2010 about the maximum current over Vin and a 1A diode is mentioned:
 
http://arduino.cc/forum/index.php/topic,27480.0.html

Yes, the 12 volts will be avaible at the Vin pin. However the maximum current draw from this pin is limited by the series polarity protection diode on the board, which is generally a one amp diode.

Is this still the case in 2013 with an Arduino Uno (R3) or can I use more current--I need up to 1.5A.

Für ein Kunstprojekt möchte ich an einen Arduino ein
- 12V, 30 mA Radarmodul
- bis zu 5 Hochvolt-Module, Eingang je 12V, <300mA

anschließen. Meine Idee war jetzt, den normalen Stromanschluss des Arduinos mit 12V zu versorgen und am Vin die 12V wieder abzugreifen (sollte doch theoretisch gehen, oder), aber geht das, besondes wenn die HV-Module im höchstfall 1,5A ziehen?? Wäre praktisch, wenn ich da die Buchse des Arduinos verwenden könnte ...

Bei Tastern usw. ist das unkritisch. Mich wunders auch, dass sogar viele, die coole Projekte machen die internen gar nicht kennen
http://arduino.cc/en/Tutorial/InputPullupSerial

Probleme kann es nur geben, wenn man mit dem pullup Einfluss auf die Sensitivität nimmt, wie etwa bei Fotosensoren, wie dem QRE1113 https://www.sparkfun.com/products/9542

Has someone tried to run the GBoard with the new lib included with IDE 1.0.4? I didn't got it work but I focused on internet connection: http://arduino.cc/forum/index.php/topic,157209.0.html