Go Down

Topic: Help making bare minimum standalone arduino. (Read 6 times) previous topic - next topic

xl97

My thread covers this same exact thing.. (with some trouble shooting) that Lefty already pointed out in here and helped me..

http://arduino.cc/forum/index.php/topic,52707.0.html

to keep things even cheaper..

1.) buy Ateml chips pre-loaded with bootloader (unless you have a real/true Arduino around to flash).. keeps cost down

2.) to keep cost down even more.. use one of the tuts outlining how to use an old cell phone data cable as an FTDI cable to upload sketches to your Arduino circuit.


carl1864

Thanks for those diagrams of the voltage regulator.  I'm still getting 2 different stories about the capacitor sizes though, I had copied and pasted from the reference and it said a 10uf and 1uf, and "retrolefty" mentions a big and small cap, but "pluggy" said he read in the reference somewhere that its 2 10uf ones, I've also heard other sources seemingly using 2 identical ones.  Does it work both ways, or is one method better?

Also, voltage regulator aside, does the schematic I posted above look all correct and problem free?

As far as the issue "selby96" mentioned about programming it.  Well I plan to just program it with a duemilanove board, and then take it out and put it in its permanent spot in its own circuit.  The purpose of me making the minimum standalone is for permanent installation.  I do all the prototyping on the duemilanove board, but once a project is done and needs no more changes, I'd like to just pop the chip out, install it permanently to the project, and pop a fresh atmega328 with bootloader into the duemilanove and move to the next project.

retrolefty

Quote
Thanks for those diagrams of the voltage regulator.  I'm still getting 2 different stories about the capacitor sizes though, I had copied and pasted from the reference and it said a 10uf and 1uf, and "retrolefty" mentions a big and small cap, but "pluggy" said he read in the reference somewhere that its 2 10uf ones, I've also heard other sources seemingly using 2 identical ones.  Does it work both ways, or is one method better?




The capacitor sizes for the regulator input and output are very non-critical. However, rather then expecting someone on the web to give you the 'perfect & exact' (or even a correct answer for that matter), you should do what most of us do, get a copy of the chip's datasheet and see what it says and recommends. That is always the reference one should go by.

Here is a link to the original national LM7805 fixed +5vdc regulator. On the very first page there is a picture showing input and output caps with notes about there usage. That input cap is shown as .22ufd, but larger is fine. The output cap is shown as not required, but .1ufd suggested. For use with digital components like the 328 chip, It's common practice to wire .1ufd caps between +5vdc and ground at various spots on your board, best location being right at the +5vdc power pins for your AVR chip, pins 20 & 22. Digital circuits create noise on the +5vdc power bus and power bypass caps are your best friend to help prevent strange problems.

http://www.national.com/ds/LM/LM340.pdf


hexskrew

I know that others have posted the usual (and very good) how-to's, but just thought I would pitch this one in just to throw in the bucket. It's the most thorough one I have seen thus far (but it's on a breadboard, but it's easier to see the concepts by this)

http://itp.nyu.edu/physcomp/Tutorials/ArduinoBreadboard

BTW, FTW -
http://www.adafruit.com/adablog/wp-content/uploads/2009/05/one-chip-arduino-v2-0.jpg[/img]]http://arpro.posterous.com/one-chip-arduino


pluggy

Capacitors in many (most ?) applications are very non critical.  The reference I was looking at for the 2 10uF capacitors around the 7805 is http://www.arduino.cc/en/Main/Standalone
If your power supply isn't particularly clean bigger is often better.   In my opinion any simpler than the RBBB is too far, you soon get sick of swapping chips when you're debugging sketches and the simple programming interface and reset switch makes life bearable. 

Go Up