I was linked this product (https://www.sparkfun.com/products/11113) and i like how small it is and it may work perfectly for what i want. I am absolutely new to this Arduino stuff and do not own one. I am attempting to build something for a project my dad is working on. Here is what it we want it to do. I have an RC airplane with 39.5 feet of leds. The plane runs on an 11.1 volt (12.6 fully charged) lipo battery. I need a program/circuit using this board preferably that will start blinking the leds at 11.1 volts to indicate low voltage then at 10.5 blink faster to indicate extremely low voltage then at 9.5 blink rapidly to indicate land now or risk the battery being destroyed. In reality it only need to do the first one at 11.1 but the other 2 voltages would be nice. I like this arduino board because it is very small and weight is key since it will be on an rc plane. Thanks!
bart796:
I have an RC airplane with 39.5 feet of leds.
errr.......bart796:
I like this arduino board because it is very small and weight is key since it will be on an rc plane.
How do you turn the LEDs on/off now?
What LEDs are you using?
And how are they wired (post a diagram or schematic) ?dlotton:
What LEDs are you using?
and 39.5 feet of 0201 LEDs is a LOT of LEDs.
I don’t think he even hooked anything up yet.
@OP: I don’t think you need 40 ft of LEDs for this project. If you do hook them all up, your battery won’t last long. You are going to need more components for this task. Just the Arduino won’t do it. Google “Arduino voltage monitor.” This should get you going.
Leds are already on the plane they work fine they are a mix of 5630 cool white strips (the majority) 5050 green, 5050 red. The leds are turned on and off by just plugging in the battery. I use basically a y cable from my battery to the lights and the ESC. If the Arduino cannot be used in some fashion that is fine. It would just be nice and convenient if the lights would flash when i have it 300-400 feet in the air so i can know exactly when it is time to bring it down and not just randomly land and realize i still have plenty of battery. Thanks for the help though i appreciate the responses.
I take it then that the LEDs are wired in some series and parallel combination w/dropping resistors, like the commercial 1 color strips you can buy. If so then why not put a power FET between the battery - terminal and the LED connection(s) that normally goes there. Then the Arduino can control the FET to turn on/off all the LEDs. As to which FET (or kit) … you’ve yet to state how much current the LEDs draw.
For this simple a task you might want to also look @ Adsfruit’s Trinket.
All the LED’s are wired together nothing special they are strips that run on 12volts. You simply solder positive and negative leads together and then provide power to one strip. I do no have any other info I apologize for this. I think my question is not going to work here due to my knowledge. Apologies for the time wasted.
Hold on there. Let’s not give up just yet. This forum is an excellent place to tackle this project. But to get it done there are some pieces of information that need to be found out. Voltage (12 volt) is only part of the answer. If you do not know how much current these ledstrips take then you will have to measure it with a multimeter:
Here’s a kit that’s likely waaaaaay more (wrt current rating) than you need.
https://www.sparkfun.com/products/10256
You’d use it as pictured here.
http://www.next.gr/uploads/20/WulWm.png
Of course your “load” is many more LEDs+resistors but it’s acts the same as shown above. And to save weight you could eliminate the screw connectors and solder wires to the board. R2 and M1 (the FET) are in the kit. You can forget about R1 as it’s no really needed for your application.
Well what I can do is when I get off work I could put a battery on it and I do have a multimeter (albeit a cheap one might not work since its just got the basics?). If you could tell me exactly what info I need from the multimeter I will post it. I am not entirely sure about the second post with the circuit drawing. Is that a solution to my problem? Or is that a way to get more info not sure what you were getting at lol
Oh I see jk I read it wrong so I could use that to connect between the LED’s and then use the arduino to flash the LEDs when it reads that the voltage is at 11.1? I don’t actually want the LEDs to turn off that would be bad since it is on a plane 300-400 feet in the sky. I simply want the LEDs to blink at a certain rate to indicate low voltage land now. Not sure if that clears any confusion up
bart796:
Well what I can do is when I get off work I could put a battery on it and I do have a multimeter (albeit a cheap one might not work since its just got the basics?). If you could tell me exactly what info I need from the multimeter I will post it.
I suggest you read through the link I posted (Multimeter tutorial by Sparkfun) . Then read the manual that came with the multimeter, if there is one.
You want to measure DC current. Amps.
Plug the red lead into the Amp hole on the meter(if there is a choice, not the mA (milliamp) one as you don’t know yet if it is out of scale) Plug the black probe into the common hole on the meter. Switch the multi-meter to the highest Amp DC scale. Connect the red and black probe in series (in between) the battery and led-strip (either between the positive terminals, or between the negative, but to both the positive and negative). It’s like the red and black leads of the probe replace one of the wires you already have. Then flip a powerswitch of the leds if there is one, and read the value of the display.
Mee_n_mac’s is a solution. Probably beefy enough not to burn through. But it never hurts to know how much current you are dealing with. Sticking the heatsink tab out into the open airflow might be required though.
bart796:
Oh I see jk I read it wrong so I could use that to connect between the LED’s and then use the arduino to flash the LEDs when it reads that the voltage is at 11.1?
Your LEDstrips would need to be above that mosfet. Or the mosfet outputs between battery minus (Ground or whatever emergency cuttof circuit minus connector) and ledtstrip minus. The mosfet wil not work if it is connected in between 2 ledstrips.
I don’t actually want the LEDs to turn off that would be bad since it is on a plane 300-400 feet in the sky. I simply want the LEDs to blink at a certain rate to indicate low voltage land now. Not sure if that clears any confusion up
Turning off is just a perpetual blink state. Blinking is like not knowing for sure if it needs to be on or off. Not sure what sort of confusion could be here. Both are the same function.
So with his solution I would need to use that trinket thing he linked to and write a little bit of code and it would effectively blink my leds when the voltage hits 11.1 provided I could figure out the code? I’m sure that is not a plug and play solution by itself?
That Sparkfun product link is just the switch part. To make it switch on the ledstrips you just have to pull one (of the 3-pin connector) high (3 to 5 volt). For turning the ledstrips off you make that pin go low to 0 volt. You still need a microcontroller/Arduino/whatever to decide when switching or blinking is appropriate, and finally to output this state on one of it’s pin that this electrical switch is connected to. The product that you linked initially is just the brains. The product that Mee_n_mac pointed to is just the ‘muscle’ , … well… pardon the mental picture: ‘sphincter’.
Ok so I order the “trinket” which is the very small arduino based board Mee_n_mac linked to and then I buy the other product Mee_n_mac linked to which was the MOSFET switch. After those I would need code to tell it when to do what I need it to do correct? The board has the ability to read the voltage without anything separate or do I still need to include more components to read the voltage coming from the battery?
Yes, that Adafruit trinket seems a very suited Arduino bord. Light and tiny. I’m sorry, I didn’t realise that Mee_n_mac also posted that one at some point. Also get the mosfet switch.
As for measuring the battery voltage. You definitely need a set of 2 resistors to make a voltage divider to reduce the battery voltage for the analog input. Just applying it to the trinket’s input pin will fry them. Which resistor values you need depends on what the absolute maximum battery voltage is (what is it?) , and the model of the trinket that you choose (3.3v vs 5v version) The voltage taken from between the resistors must come out below the 3 or 5 volt. A potentiometer could be a flexible alternative for this. (10 kOhm should be ok) As it could also be used when you are just learning how to measure analog voltages in Arduino. (during testing it’s alot easier to just turn a potentiometer than to wait until a battery is drained) An additional led and current limiting resistor could help identify what state the output pin to the mosfet’s gate is. As pin-state and gate voltage is invisible otherwise.
p.s. I don’t know how stable a potentiometer is in flight conditions though. I mean, if it is influenced high up in the windy air, humidity/moisture and what not. Once you have settled on a good voltage divider ratio after testing you could buy 2 appropriate resistors to replace the potentiometer. But you can ofcourse also buy a resistor assortment pack right away if you are serious about your electronics hobby.