I intend to just power and run the Quad-copter from my computer at first, and add a radio signal afterwards.
my questions are:
Could I just use one Lithium polymer battery( like a 14.8 V, 3 amp battery?) to power all 4 ESCs?
Should I use a PWM shield on the Arduino Uno, or just use 4 PWM pins on the Uno?
From veterans of this type of project, is there anything I should be wary of before I get started?
You can't use a 4S battery with an arduino UNO external battery power barrel jack.
The maximum voltage allowed is 12V and technically even a 3S (12.54V charged) is too high for that.
A 2S is 8.4V dc which is the perfect voltage for the external barrel jack. Get a small 2S battery (I use 1350mAh, 2S) for the arduino UNO
power. Never run the controller for a quadcopter off the ESC battery. That's just plain stupid. (not that you were planning to do that)
So then one 2s battery will be sufficient to run the 4 ESCs?
Also, if i use a 2s battery will that mean that the motors I use will also have to be rated for 2s?
No one is talking about running any ESCs from a 2S battery (at least I am not)
I said you should run the arduino off a 2S. I didn't say anything about changing the battery you use to power the ESC/MOTORS.
No , you can't power the motors with a 2S battery.
My apologize, I read your reply completely incorrectly.
Let me see if I understand now,
The general idea is:
Arduino Uno (powered by a 2s 1300 Amp battery)
-connected to-
ESC (powered by a 3S Lipo battery ,if ESC is rated 3S)
-connected to-
motors (current draw is less then max current output of ESCs)
with the ESC being connected via the PWM pins of the arduino.
with the ESC being connected via the PWM pins of the arduino.
This is completely wrong because an ESC doesn't use PWM. It uses PPM
In the early 1960s, Don Mathers and Doug Spreng of NASA invented Pulse Position Modulation used in Radio Control (R/C) systems. PPM is currently being used in fiber optic communications, deep space communications, and continues to be used in R/C systems.
I am not sure if this is a mistake or not:
ESC (powered by a 3S Lipo battery ,if ESC is rated 3S)
-connected to-
motors (current draw is less then max current output of ESCs)
with the ESC being connected via the PWM pins of the arduino.
but just for the record, if the arduino is powered by a 2S battery, it doesn't matter if your quadcopter ESC and motors are powered by a
9S battery.
I could be wrong (it certainly has happened), but as I understand it, the "standard" for radio control as it has developed, is that the signal transmitted is Pulse Position Modulation insofar as the timing between successive pulses in the transmitted cascade, codes the individual channel pulse widths, and the decoder, a simple 4017, "dices" that cascade into individual pulses whose width contains the information, so the servos - or ESC - are indeed fed with PWM.
Your concern here is that this is simply a quite different form of PWM than the "PWM" function intrinsic to the ATmega chips that may be employed for quite different purposes, but it most certainly and unquestionably is PWM.
True , but you knew all along that he was referring to the PWM pins (because he stated that explicitly) so if you want to split hairs it is NOT the PWM that HE was talking about (and for that matter your explanation about the 4017 (which I'll bet he is not familiar with ) was probably over his head so that's a moot point)
Thank you again for the help, I really appreciate it.
I should have said that I am not at all experienced with electronics or arduino, ( I'm a junior in college right now, with only a semester of electronics under my belt)
thank you for the ppm advice, I will use PPM instead. I was only thinking of using a 3s battery for the ESCs because the total frame is only going to be 250 mm in size, and I'm just worried that a bulky 9s battery will be to heavy to carry, let alone 4 of them.
Side note : how did you know I was male, or did you just assume by my name I was?
and I'm just worried that a bulky 9s battery will be to heavy to carry
LOL , XD
You knew I was just exagerating about the 9S battery didn't you ? !
how did you know I was male, or did you just assume by my name I was?
I've never heard of a name like Fikre so it definitely wasn't the name.
Ask yourself this,
When was the last time you heard a teenage girl turn to her girlfriends and say "Would you excuse me please, I have to go work on my Quadcopter. I still have some ESCs to wire up and I need to order a 3S battery ..."
The first being power. What voltage battery you need depends on how heavy your quad will be and how large your props are. You need to be able to spin the motors/props fast enough to give you hover at about 50% throttle. For NTM motors that's likely 3S unless your'e going to be horribly inefficient.
Secondly on the power front. It's very likely your ESC's supply a fairly clean 5v back down the VCC pin of the servo connector. You can use that to power the arduino.
You need more than you have written to have a controllable quadcopter, you need an accelerometer and gyroscope ideally before you can form any sort of control system. Once you have those you need to code a PID loop that runs on the Arduino and then tune it for your particular quadcopter.
Lastly, the ESC's aren't technically PWM or PPM, it's more of a not quite standard PWM than anything else but look at the servo library for more information.
Finally, you're really inventing the wheel here. Quad flight controllers are cheaper than a standard Uno these days with all the sensors. If you're doing this to learn then go for it, if you want a flying quadcopter just buy a flight controller
Some example code you may want to look over can be found by googling MultiWii
It's very likely your ESC's supply a fairly clean 5v back down the VCC pin of the servo connector. You can use that to power the arduino.
Never run the controller for a quadcopter off the ESC battery. That's just plain stupid. (not that you were planning to do that)
This is basically true for fixed wing because you need the servos to land if you fry your ESC (trying to fly to fast)
Because if you fry the ESC that is supplying the 5V you will lose your controller power and will drop out of the sky. On the other hand, with a Quadcopter, if you lose one of the ESCs your dead anyway.
Lastly, the ESC's aren't technically PWM or PPM, it's more of a not quite standard PWM than anything else but look at the servo library for more information.
SEE REPLY #5 (the Wikopedia links (It's called PPM. It was invented by NASA and it is distinctly different from the PWM of the arduino PWM pins.
You need more than you have written to have a controllable quadcopter, you need an accelerometer and gyroscope ideally before you can form any sort of control system. Once you have those you need to code a PID loop that runs on the Arduino and then tune it for your particular quadcopter.
Finally, you're really inventing the wheel here. Quad flight controllers are cheaper than a standard Uno these days with all the sensors. If you're doing this to learn then go for it, if you want a flying quadcopter just buy a flight controller smiley
I have to agree with these last two comments. There are many good flight controllers available now so unless this is a homework assignment or you're a masochist it just make more sense to buy something off the shelf. I didn't see anything in your post stating that your "cheap" (we get that a lot) so you might want to shop around and see what's out there.
