9v >> 5v On the MINI  & Atmega8 standalone Qs

Forum 2005-2010 (read only) General Frequently-Asked Questions
1

Hi there,

Im planning to use an arduino mini on a RC helicopter.

  1. Would it be possible to run the mini power from a 7.2V battery pack to the +9V of the mini ?
  2. Would the arduino mini then output a regulated +5v at any pin so i can run a 5v sensor? (possibly the +5v pin at the top or bottom??)

Also, on another note,
3. if i buy an arduinoNG and flash the program to it, then remove the atmega8 chip can i just connect the corresponding pins as i would the arduinoNG pins ? (ie no need for any other hardware / ?bootloader? etc etc)

  1. Does the standalone ATmega8 need exactly 5v to run?
  2. And, finally, does just the standalone atmega8 have the ability to convert 7.2V to 5v ? (unlikely eh)

Thanks a lot,
cya
R

2

Don't know what you plan to do with your arduino, but you might find this project interesting:

http://home.arcor.de/d_meissner/d_logg2_engl.htm

3

Further to Daniel's answer to your question 3, you might want to check out
http://www.arduino.cc/playground/Learning/AtmegaStandalone
Here, I have gathered many of the resources for atmeta8 / 168 standalone use.

I think the single best tutorial on how to build one on breadboard is here:
http://itp.nyu.edu/physcomp/Tutorials/ArduinoBreadboard

If you're following these plans, make sure to pay attention to Daniel's tip above on replacing the 7805 regulator with something that can handle your lower input voltage.

4

Thanks a ton guys,

@brainfart - i am starting off by putting a gyro on a cheap heli and modulating the tailrotor to keep it from yawing - (Maintenance) and then will proceed to add on things from there.

@Daniel - Thanks for the info. Good point on the low dropout voltage regulator! thnx. I have a stupid Q regarding the crystal (see #6 below)

@Neilzero - Thanks for that page. It REALLY helped me get a better understanding of most of the concepts of standalone atmega, and a lot of the links on the page were useful too!

Here are a few more Qs i had -

  1. Heres the stupid Q - if i use the atmega's internal crystal/oscillator, which i have read is equivalent to 1Mhz, would that mean my atmega will be running at 1/16th the speed compared to if i used an external 16MHz crystal? (So in a sense a 16MHz external cryztal is "overclocking" it?)

  2. Mellis mentioned that you can use a Wiring board (which i have) as an AVR-ISP (http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1158265039/5) Where could i find info on that ?

  3. If i program the atmega168 via wiring board, will it be able to put a bootloader on as well as upload the program i write? or will it only do the bootloader and i will have to put it in my arduinoNG to upload the program ?

  4. Any useful links of people using gyros with their own microcontrollers in helicopters? or for anything else?

  5. Would i be correct to assume that a gryo will only show a rate of change if there is rotational movement about its axis, and not if it is moved around on a horizontal plane without any rotation?

And also, if you guys could help with Q1 & 2 from the original post :smiley:
Once i have that figured i will buy my mini! (also would like to buy one of these!! > http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1167665675)

Thanks a lot,
Really appreciate the help,
RB

5

I guess you guys can leave out Q6 as i got the answer here -

http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1163418637

cya
R