Yes I understand that there are resistors in the LED strip and that I do not need a resistor in series with the LED strip.
"resistance" of the LED strip is a spurious concept, since it is nothing remotely like a linear relationship
between voltage and current.
Thank you for all the replies and sorry for my inactivity.
I think I am ready to buy components, where on the internet should I look to buy these? I've seen that there are multiple Arduinos from which I can choose. Can you give me some insight into what type I should choose?
EDIT: Do you have some advice on what components to select, i.e. model/type/etc.?
Jori:
Thank you for all the replies and sorry for my inactivity.I think I am ready to buy components, where on the internet should I look to buy these? I've seen that there are multiple Arduinos from which I can choose. Can you give me some insight into what type I should choose?
EDIT: Do you have some advice on what components to select, i.e. model/type/etc.?
As a first time arduino user, get the Uno board then maybe a breadboard or protoboard shield to put your components on.
Available from ebay or your local Electronics retailer.
I am planning on using a 9V or 12V battery for powering the LED strip. Am I correct in saying that I should connect the plus side of the battery to the LED strip and the emitter side of the transistor to the minus side? Does this not pose a problem as I should have a wire running from the emitter side to the Aruino GND to 'close' that circuit (starting at the PWM output)?
I am lacking knowledge in this department so an easy explanation would be very nice.
Thanks!
Jori:
I am planning on using a 9V or 12V battery for powering the LED strip. Am I correct in saying that I should connect the plus side of the battery to the LED strip and the emitter side of the transistor to the minus side? Does this not pose a problem as I should have a wire running from the emitter side to the Aruino GND to 'close' that circuit (starting at the PWM output)?I am lacking knowledge in this department so an easy explanation would be very nice.
Thanks!
See the previous circuit you referenced, your LED strip is the Load being switched there, the negative of the LED supply battery is connected to the Arduino ground/0V connection.
The positive side of the of the LED supply battery is connected to LED strip ONLY.
So, you have two totally separate power supplies/batteries, a low voltage one supplying the arduino and the 9/12 volt supply for the LED strip.
You could run both from the same supply, but the regulator on the ardunio may get a bit warm.
This might be interesting for you Jori: ABC - Arduino Basic Connections - Project Guidance - Arduino Forum
astrofrostbyte:
This might be interesting for you Jori: ABC - Arduino Basic Connections - Project Guidance - Arduino Forum
Nice diagrams, will there be PDF version?
The graphics are very clear, but I had to make my browser full screen.
I think/hope so, this is the authors website : http://www.pighixxx.com/
astrofrostbyte:
This might be interesting for you Jori: ABC - Arduino Basic Connections - Project Guidance - Arduino Forum
Wow this is great, thank you!
Hi all,
After a very long time, I've ordered and received the Arduino Uno.
I hope you remember what I wanted to achieve, to recap:
- I have an Arduinu Uno.
- We want to have four LDR (each on a separate, small 'circuit') connected to the Arduino.
- We have four LED strips (each on a separate 'circuit') of 300 mA on a power supply of 12V.
- We want to control the brightness of the LED strips.
- We use an NPN transistor to do this.
So, as the Arduino cannot provide 12V, we use a seperate battery of 12V to power the LED strip. We therefore have to use an NPN transistor. We connect the base of the NPN transistor to a digital (PWM) output of the arduino. The collecter side is connected to the LED strip. The emitter side of the transistor should be connected to the GND of the Arduino. Earlier, someone stated that I should connect the negative side of the battery also to the GND of the Arduino.
My question still is, how do I do this? I see that there are 3 GND ports on the Arduino (2 under POWER, 1 under DIGITAL (PWM~)), so which ones do I chose? Is it possible to have four circuits using the LED strips?
And is it even possible to connect 4 LDR on separate circuits to the Arduino? I only see one 5V port under POWER.
Sorry for my lack of experience with these things.
Thanks in advance.
Jori
GND is connected together, you can use any, all (one leg of) the LDRs can be connected to the 5v supply, the other 4 wires from the LDRs (with a resistor to ground) go to the 4 analogue ports of the arduino.
Here`s a random link to a an LDR circuit
Duplicate that circuit four times and connect all the supply and GND`s together.
Thank you Lakes, I understand how to make the LDR circuit.
Just to be sure I also understand how to make the LED strip circuits:
On my Arduino Uno there are three GND pins, lets call them GND A, GND B (both on the POWER side) and GND C (DIGITAL side) (for reference: http://arduino.cc/en/uploads/Main/ArduinoUno_R3_Front.jpg).
For the LDR circuits, I have four wires from the 5V on the Arduino each going to the LDR. For each LDR I use an analog input to read its value and connect it through a resistor to GND A. So, 4 wires coming out of the 5V pin, 4 wires going to A0,A1,A2,A3, and 4 wires going to GND A for the LDR circuit.
For the LED strip circuits, I have four wires going from the plus side of the 12V battery, each to the LED strip. The other side of the LED strip is connected to the collector side of the NPN transistor. From four DIGITAL PWM pins (e.g. 3,5,6 and 9) I have a wire to the base of a NPN transistor. From the emitter side of the transistor I have a wire going to GND C (on the DIGITAL side), this means I have four wires going to the GND C in total. I then connect the GND B to the negative side of the battery, so just 1 wire.
Can you tell me I understood it correctly?
Many thanks!
Jori
Yup, sound/reads 
correct to me.
Each PMW pin goes (through a resistor) to the base of a transistor, all emitter connections go to GND, either power or digital, collector goes to one side of the LED strip, other side of the (each) LED strip connects to 12 volt supply.
LED Strip has a common 12v supply (four wires), wire from other side of LED.
if you connect a meter set to resistance (low ohms), you will see that power GND and digital GND are connected together.
In the time its taken to type describe this it would have been quicker to sketch a diagram and scan it. lol
(I will maybe do that later)
Jori:
@sonnyyu
The phone in the box is always different and we do not want to setup things before they put it in the box. Think of an exposition where customers come to look at her project and they insert their own phone in the box. This could be any random person on the exposition. Thank you for the input though.
sonnyyu:
why not use Voice over IP server as gateway.http://arduino.cc/forum/index.php/topic,57499.0.html
caller id support , different caller, different led on.
SMS gateway support, different led on base on number.
email gateway support, different led on base on email address.
Voice mail support, different led on base on how long the message is.It is no long phone, it is call center.
p.s. U need first forward number to VOIP box, then u could turn phone off and throw it out the window. every thing should still work.
Plan B or Upgrade Plan;-
VOIP box is associate with phone number, i.e. 212-555-1212.
When customer in ask them
Activate Call Forwarding:
Dial *72 or 72#.
Dial the number (212-555-1212) to receive forwarded calls. customer carry the phone as usual.
When customer out ask them
Deactivate Call Forwarding:
Dial *73 or 73#.
Now we support more than one customer at time, and no manage the customer phone. All you did so far will be part of system. The VOIP box need Arduino to interface with LED. VOIP software is opensource , the phone number could cost as low as 0.99/month, even free. The VOIP box could host on any pre-love unused computer (minimum system requirement is a Pentium 4 processor and 512 MB of RAM).
add minimum system requirement
is it me, or is the 555 timer, bloody great!
If you wanted to impress, detect the radiation levels near to the phone, be sms, ringing.... etc then have a circuit act on that?
good found.
The detail of L1?
Mobile incoming call indicator
admin
June - 7 - 2008
115 CommentsDescription.
This circuit can be used to escape from the nuisance of mobile phone rings when you are at home. This circuit will give a visual indication if placed near a mobile phone even if the ringer is deactivated.
When a call is coming to the mobile phone, the transmitter inside it becomes activated. The frequency of the transmitter is around 900MHz.The coil L1 picks up these oscillations by induction and feds it to the base of Q1. This makes the transistor Q1 activated.Since the Collector of Q1 is connected to the pin 2 of IC1 (NE555) , the IC1 is triggered to make the LED connected at its output pin (pin 3) to blink. The blinking of the LED is the indication of incoming call.
Circuit diagram with Parts list.
mobile-incoming-call-indicator-circuit.JPG
Notes.
The coil L1 can be made by making 150 turns of 36 SWG enameled copper wire on a 5mm dia plastic former.Or you can purchase a 10 uH coil from shop if available.
The circuit can be powered from a 6V battery.
Assemble the circuit on a good quality PCB.
C1 & C3 are to be polyester capacitors.
The electrolytic capacitor C2 must be rated 10V.
cjdelphi:
is it me, or is the 555 timer, bloody great!
If you wanted to impress, detect the radiation levels near to the phone, be sms, ringing.... etc then have a circuit act on that?
Yes, the 555 is an extremely useful IC!