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1  Using Arduino / General Electronics / Re: Voltage fluctuating too much. How to fix? on: November 22, 2012, 10:27:36 pm
Would that solve the problem? What about the ground lines, does it matter if I power the sensors from a separate 5V regulator but ground them to the Arduino's pin?
2  Using Arduino / General Electronics / Re: Voltage fluctuating too much. How to fix? on: November 21, 2012, 06:53:27 pm
I was thinking that maybe I should make a separate power line for the buzzer and the LCD backlight as they are drawing too much current? Or maybe put the two sensors on their own 5V regulator and all the rest on a separate 5V regulator?
3  Using Arduino / General Electronics / Re: Voltage fluctuating too much. How to fix? on: November 21, 2012, 06:43:02 pm
My LCD has a resistor built in the backlight so I don't have to put one.

However, the Arduino is a cheap Chinese knock off. How can I know the regulator's specs? Is there a way to see just looking at it?
It says AMS 1117 on the regulator and outputs 5.15V without any load.

On my genuine Arduino it outputs 5.00V without load.
4  Using Arduino / General Electronics / Re: Voltage fluctuating too much. How to fix? on: November 21, 2012, 05:15:16 pm
I received this 9V adapter, 650 mA. It outputs 9.21V without load.

The voltage is better (5.07V on 5V pin) but when I turn the LCD backlight on it still drops to 4.67V.

Is there a way at all to keep a constant 5V on the 5V pin?
5  Using Arduino / General Electronics / Re: Voltage fluctuating too much. How to fix? on: November 18, 2012, 12:48:43 pm
Ok so I bought a 9V 650mA adapter, I will update when I receive it
6  Using Arduino / General Electronics / Re: Voltage fluctuating too much. How to fix? on: November 18, 2012, 01:11:05 am
Plus, the ADC can reference an internal 1.1V reference. That would be more reliable probably than the fluctuation you might get on the 5V line. You might need a voltage divider so that you don't input more than 1.1V on the analog pin, if you choose to use that.

Could you elaborate on that please?
7  Using Arduino / General Electronics / Re: Voltage fluctuating too much. How to fix? on: November 18, 2012, 01:10:46 am
I changed the wire so the power rail is fed from the 5V.

I checked the power rail once fed from the 5V pin and it does output the same as Vin, that is to say around 4.55/4.65 depending on the USB/DC jack combinations stated in the first post.

Nothing gets hot and the wallwart is the one I got from Adafruit with the thermal printer. It works fine with the printer + ethernet shield.
8  Using Arduino / General Electronics / Voltage fluctuating too much. How to fix? on: November 17, 2012, 11:27:52 pm
Hi all,

I have put together a project to monitor the temperature of our fridge and freezer. The fritzing schematics (sorry) are attached to this message.
It will calculate average temp, trends and a whole lot of other things. If the temperature is out of acceptable limits then it will sound an alarm and repeatedly blink the LCD backlight. One button is for silencing the alarm via an interrupt and the other one is to manually turn on the LCD backlight should one want to see the screen in the dark.
In other words, it is an over-engineered thermometer.

The problem I am having is that my temperature sensors are analog. Thus they need a constant voltage to return accurate and calibrated values.
This is not the case however. Voltage varies a lot:

When I power the whole thing up with a 5V 2A AC adapter, voltage on the 5V pin and the Vin pin is 4.55ish.
When the screen is blinking/the backlight is on, it drops to around 4.30V
If I plug in both the AC and the USB, the 5V and Vin pins are around 4.67V
It drops to around 4.40V when there is backlight activity.
I checked the output of the AC at the plug and it's 5.39V

Where does my problem stem from? Is my whole “system” using more that 2A? It seems like a rather hugh value doesn't it?
How can I make the 5V deliver 5V so that I don't have to tweak the code every time I change the way it's powered?

I plan on moving everything to a PCB once these problems are ironed out powered by a standalone atmega328 without a USB serial interface. I was thinking I could power it with AA batteries. Is it feasible or is it using too much juice?

I'm not very experienced to all things electric/electronic so please be patient and detailed in your answers.
Thanks for your help!


--edit: A more readable image size than what the forum offers



9  Using Arduino / Project Guidance / Re: What kind of LEDs to grow plants? on: October 19, 2012, 11:18:33 pm
This is a cheap DIY endeavour, it's to grow parsley and chive. How many watts are enough for that you reckon?
In your link it is not clear whether it's a mix of red orange blue white LEDs or purple LEDs?
10  Using Arduino / Project Guidance / Re: What kind of LEDs to grow plants? on: October 19, 2012, 10:28:57 pm
Google doesn't work for you?

Google returns a lot of conflicting information on that matter, saying everything and its opposite
11  Using Arduino / Project Guidance / What kind of LEDs to grow plants? on: October 19, 2012, 07:22:29 pm
Hi all,

I am thinking about making a growing system for a few indoor plants (spices) that receive very little light.

What LEDs (colour and wattage) are best suited for this? Anyone with previous experience doing this?
The internet has a lot of conflicting information.

Thanks,
12  Using Arduino / Microcontrollers / How to program the ethernet card? on: October 06, 2012, 03:55:19 pm
Hi all,

I bought this ethernet card:
http://www.buyincoins.com/new_en/details/new-enc28j60-ethernet-lan-network-module-schematic-for-arduino-51-avr-lpc-stm32-product-9026.html

And I am trying to make it work with my Arduino.

I also have this programmer:
http://www.buyincoins.com/new_en/details/usbasp-isp-programmer-adapter-10-pin-cable-for-atmega8-avrdude-can-pwm-series-product-12139.html

I thought I could connect the programmer to the ethernet card, plug the other side in the USB and upload the ethernet controller sketch from the Arduino IDE.
It turns out it's not so easy.

Could someone please advise?
I don't even know how to interface the ethernet card and the USB programmer, the programmer has 6x2 pins, the ethernet card has 5x2 pins…

Thanks for your help!
13  Using Arduino / Microcontrollers / Re: How to burn the bootloader on a standalone atmega328p? on: September 06, 2012, 11:09:55 pm
Thak you all, I will try this and let you know if anything
14  Using Arduino / Microcontrollers / How to burn the bootloader on a standalone atmega328p? on: September 05, 2012, 08:47:06 am
Hi all,

I have a USBtiny clone programmer and an Atmega328p blank chip.

I would like to burn the Arduino bootloader onto the Atmega but I can't find how to connect the chip to the programmer.

Can anyone advise?
Thanks
15  Using Arduino / Programming Questions / Re: On naming variables, functions and constants on: June 08, 2012, 05:52:26 am
Thanks!
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