Im have build and programmed a small quadcopter and now its finally flying (cost me a few sleepless nights) :o
Now i want to rebuild the hole thing to make it more solid and nicer.
I use 4 small dc motors + gear from my old UDI818 quadcopter the run on a 1S 3.7 lipo.
The arduino is running on a different 9v battery.
in my new setup i want to use a 2S lipo (7.4v) and put the cells parallel for the dc motors (3.7v) and in series for the arduino (7.2).
Would it be a problem to run it from the same power source?
I dont have any capacitors on it and no problems (but thats maybe because it runs from a different source) do i need to add them and on what value would i use?
Im now using 4 mosfets type 14N03H i have them from a old pc and the seem to work good but i need to buy 4 new ones so what would be the best option ?
You cannot have the same pair of batteries both in series and in parallel. Draw out how that would be connected, and you'll see that it would involve shorting out one of the batteries.
Either use a 3.3v arduino and batteries for power, or use a little boost converter the get the 5v for Arduino (polulu makes nice, fairly expensive ones, eBay sellers in china make very very cheap ones)
in my new setup i want to use a 2S lipo (7.4v) and put the cells parallel for the dc motors (3.7v) and in series for the arduino (7.2).
Have you tried drawing that schematic? The batteries can't be in series & parallel at the same time.
If 7.2V is too much for the motors, a switching voltage regulator will be very-efficient and that efficiency means two batteries will last (about) twice as long as one battery. But of course, the additional circuitry adds weight.
As far as capacitors and power supply noise, that's hard to predict. It's equally hard to tell you what capacitors to use or if capacitors alone will take care of any problems. These things require experimentation. But, the Arduino board has a voltage regulator that provides some filtering (generally better filtering than capacitors alone).
thats stupid, luckly i didnt try it..
I hope i dont need to add more weight to it.
I can try to run the motor on the 2s lipo and see if its working.
Or run the arduino on 3.3v but then its not running on 16mhZ anymore??
and i think my GPS needs 5 volt.
oke i think i will buy this unit: Pololu 5V Step-Up Voltage Regulator NCP1402 and power the arduino with it true the 5v pin.
But now i just found this on the internet.
"The FTDI FT232RL chip on the Nano is only powered if the board is being powered over USB. As a result, when running on external (non-USB) power, the 3.3V output (which is supplied by the FTDI chip) is not available and the RX and TX LEDs will flicker if digital pins 0 or 1 are high.
Im using a Nano and i need the 3.3V for the barometer, but im running it now from 9v and the 3.3v does work...
The Nano schematic clearly shows the FT232 is powered from 5V, whether that 5V is from the regulator, 5V header or, 5V by way of USB thru diode, so the USB comment would seem incorrect.
Michel000:
can i just power the motor true the 5v output from the arduino ?
I read it can supply 900mA i believe my motors are using 100mA * 4 = 400mA (not sure because i dont have the specs of them)
5v is only 0.8v difference with a fully charged 1s lipo
You motors will be taking several amps each, if they were running on 100mA
for a copter of that size you'd have improved the state of the art by a massive
factor.
i just put a multimeter on the motor and its using 600mA (without a prop), and with a bit of pressure on it it will go up to 3 Amp.
I thought i found the same motor and that one had a rated current of 100mA, but clearly i have a different one.
Hovering flight is incredibly power hungry - much more so than winged flight. The
typical flight endurance with high energy density LiPo batteries is of the order of 10
to 15 minutes, and power levels are dozens to hundreds of watts.