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1  Products / Arduino Due / tinyFat Library with Due on: February 10, 2013, 03:52:20 am
I was wondering if anyone had figured out how to use Karlsen's tinyFat and UTFT_Tinyfat librarys with the arduino due.  His UTouch and UTFT libraries work out of the box with the due and my 5.0" lcd screen but his SD card library doesn't.

I know there is an SD card library that works with the due, but I am looking to load images from the sd card and display them on the screen.

Any help would be appreciated!
Nick D.
2  Using Arduino / Microcontrollers / Re: Atmel Studios 6 Issues on: February 07, 2013, 02:00:35 am
Tested it out on an atmega328p dip version and it still failed with the correct crystal in place.  Luckily, I noticed that I had replaced one of the 22pF caps with a 0.1uF cap, which was causing the problem!

Nick D.

3  Using Arduino / Microcontrollers / Re: Atmel Studios 6 Issues on: February 07, 2013, 01:32:51 am
I think I have found my issue, I apparently ordered series load crystals instead of parallel.  I have a crystal lying around I know is parallel and will try replacing it tomorrow to see if that does it.
4  Using Arduino / Microcontrollers / Re: Atmel Studios 6 Issues on: February 06, 2013, 08:23:07 pm
I have the chips in circuit with a 16mhz crystal and two 0.1uF caps.  These was in place when I could read the device signatures.  It stopped working the first time I tried to program the fuses. 

I had picked Ext Crystal Osc.; Frequency 8.0- MHZz; start-up time PWRDWN/RESET: 16K  CK/14CK + 65ms;

The programmer didn't even finish programming the fuses so that can't be the problem, correct?  I am trying to read the device at 250KHz and I get nothing.

Thanks for the help!
5  Using Arduino / Microcontrollers / Atmel Studios 6 Issues on: February 06, 2013, 04:18:17 pm
Hello Everyone,

I am having the worst possible experience trying to work with atmel studio 6 and am looking for a bit of help.

I am using Atmels avrisp mkII programmer to try and burn the arduino bootloader onto some atmega328P-AU and atmega328-AU chips, I have both.
I am running avr studio 6 on windows 8 beta through VMfusion as I don't have access to any windows machines.

After finally getting atmel studios to connect to the avrisp mkII and update the firmware I tried to read the chips through their isp connection and couldn't get a reading.  I figured that the chips may have been bad due to messing with the avrisp on a mac trying to burn the bootloader through the arduino software so I replaced the chip with a brand new one (Atmega328P-AU).

With the new chip I was able to get a good reading on the chip and everything worked fine, I programed the optiboot into the chips flash and everything was still okay.  I then went to program the fuses to 0xFF LOW 0xDE HIGH and 0x05 Extended.  When I clicked program fuses I received the error "command failed due to previously failed command" then I get a message saying it cannot enter programming mode.  Now I cannot read the at all anymore.  I tried on another atmega328P-AU chip but this time didn't program the bootload, I read the chip, everything was fine, went to set the fuses, same error.

I was successfully able to program an attiny85 chips fuses with no issues whatsoever.

Does everyone have a hard time working with the avrisp mkII, there seems to be a lot of people running into issues with it?
If anyone was any advice on getting this to work it would be much appreciated.

Nick D.
6  Community / Exhibition / Gallery / Re: LED and aquarium controller with TFT LCD touch screen on: January 28, 2013, 04:35:08 pm
Vasco,

I want to thank you as seeing your controller a few months back was one of the main reasons I decided to try and make my own.  For ATO I have implemented freescales MPXV5004GC7U pressure sensor in order to get accurate water levels.  It is extremely simple to use and is quite accurate.  Here is a link to the product
http://www.digikey.com/product-detail/en/MPXV5004GC7U/MPXV5004GC7U-ND/951844

Nick D.
7  Using Arduino / LEDs and Multiplexing / Re: Dimming 1w leds with transistor and walwart issues on: December 09, 2012, 04:00:22 am
Alright I got four of the second circuits all setup in eagle.

The mosfet will dissipate (5v - 3.3v - 0.65) * 0.350A = 0.37w
-where did 0.65 come from?  Voltage drop of the Logic Level FET?


According to his formula to find the resistor value for R3 I should be using a 1.5ohm resistor, do these exist?  If I bump it up to 2 ohms my max current goes down to 250mA which is acceptable but still lower than i'd like.

He is using a Fairchild FQP50N06L for the Logic level FET, and a Fairchild 2N5088BU for the NPN transistor with a 100K ohm resistor for R1.  Will all this work as planned?

I appreciate everyones help very much, I am learning quite a bit!
8  Using Arduino / LEDs and Multiplexing / Re: Dimming 1w leds with transistor and walwart issues on: December 08, 2012, 06:11:03 pm
Thank you very much for the explanation!

So the switch-mode constant current drivers shouldn't be pwm'ed?

So are you saying the ZTX851 would be better to use than a logic level mosfet but still not better than getting a constant current source with a dedicated pwm pin?

Can I build this circuit instead of buying a different pwm constand current driver?
http://www.instructables.com/id/Circuits-for-using-High-Power-LED-s/step8/a-little-micro-makes-all-the-difference/
9  Using Arduino / LEDs and Multiplexing / Re: Dimming 1w leds with transistor and walwart issues on: December 08, 2012, 09:24:13 am
I don't know what the linking rules are here so hopefully this is alright.
http://www.rapidled.com/moonlight-driver-350ma/

Although it has a varying voltage for 1 to 4 leds.  So all four of my leds would be dimmed at the same time if the pwm signal connected to it.

so a power mosfet such as the IRF510 will work fine without heating up too much?
10  Using Arduino / LEDs and Multiplexing / Re: Dimming 1w leds with transistor and walwart issues on: December 08, 2012, 08:24:19 am
with a 220 ohm it still get too hot to touch very quickly.
11  Using Arduino / LEDs and Multiplexing / Re: Dimming 1w leds with transistor and walwart issues on: December 07, 2012, 06:43:55 pm
I noticed that when I keep the led at 350mA, which I tested with a meter, the 2n2222 transistor gets very hot very quickly.  So since this is too much current for the npn's can I use a TIP120 Power Darlington Transistor from adafruit for the job?
12  Using Arduino / LEDs and Multiplexing / Re: Dimming 1w leds with transistor and walwart issues on: December 07, 2012, 06:26:06 pm
fungus,

I did know this already and have a constant current driver that will supply voltage to one or all of the leds, that was actually the first ting I tried to dim them with before the 5v source.  Since it didn't work as I did not provide the common ground I just assumed that the constant current driver just pumped out more current to compensate for the dimming and keep the led at its max.

I just hook up the circuit with the constant current driver and it is all working as it should, thank you very much!
If you know of  place off the top of your head, is their a website that provides basic electrical knowledge and covers a wide basis of topics?

Nick D.
13  Using Arduino / LEDs and Multiplexing / Re: Dimming 1w leds with transistor and walwart issues on: December 07, 2012, 04:31:25 am
Fungus,

Thank you very much it is working perfectly now!
I'm glad I learned that, it makes a lot of sense!


I am mainly testing this with two double A batteries as its closer to 3v, but at first I was using the 5v walwart with a 10ohm resistor and it seemed to be okay for the short tests I was doing.  I will be buying a 3 volt walwart to run them as together they will take upwards of 1.4 amps.

This is ultimately for moon light control for a reef tank.  I was planning on having four 1w leds wired in parallel each individually dimmable to simulate to lunar phases and cloud cover.
I am also wondering, would it be better to run the leds off of a 3volt walwart or to get a 3.3volt voltage regulator to convert a 5v supply?  I am guessing the voltage regulator would be a lot more stable, yes?

I appreciate your help, I still have a lot of learning to do on the hardware side!

14  Using Arduino / LEDs and Multiplexing / Dimming 1w leds with transistor and walwart issues on: December 07, 2012, 03:57:05 am
Hello Everyone,

I am trying to dim a 1w led (3v 350ma max) with a pwm signal from the arduino.  I have a simple circuit using a 1k resistor on the base pin of a 2n2222 NPN transistor with the emitter connected to ground on the arduino and the collector to the negative terminal of the led.  The positive led terminal than goes to 5v on arduino.

This circuit works perfectly fine and I am able to get it to dim correctly, however, I need to run the leds from a separate 5v power supply (walwart) while still controlling the base pin with the arduino.  For some reason every time I replace the ground and 5v from the arduino with the ones from the walwart, the led will not light while using the arduino pin to control the base.  If I connect the base to the positive terminal of the walwart the led will turn on.

I do not have a great understanding of circuit design as of yet and feel like I am missing something small so any help would be greatly appreciated!
15  Using Arduino / Displays / Re: 3.2 Sainsmart TFT touch issues on: September 08, 2012, 01:57:31 am
I am not sure if your issues are the same as mine where, but I bought a sainsmart 3.2" TFT LCD Screen about a month ago and had roughly the same issues, it ending up being that the touch screen was just installed upside down?

So to fix that I now have to subtract the y-axis value I want from 240 to get the correct response...
Kind of annoying, but it still works.  I am really not thrilled with sainsmart to be honest, they have such a wide variety of products that all seem to work, I just don't understand why they can't provide information about how to use them with the products.
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