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1  Development / Other Hardware Development / Re: barebones leonardo pcb on: January 02, 2013, 09:43:25 pm
"wireless/ethernet is not needed for many projects."

Crossroads, I completely agree from a engineering, practical perspective. But, for me it's not about need, it's about the next step in capability. The arduino wasn't needed. People got along fine with a blank atmel and assembly or C. But it's transformative. Make and arduino - for the same price or cheaper - than the standard arduino but with a built in transceiver (really should be wifi) and you'll change everything.

Anyway, I look at your board and circuit. You have already done most of what I wanted. And I learned a lot while looking at it. If its alright with you, I'll use it as a reference, with mine. I've come to realize that - as much as I reinventing the wheel is bad - it's highly educational, and I think I'm doing myself a disservice by copying so much directly.

I noticed you are available for design services. Does that mean I can contract you to take a solid look at my eagle files and get some feedback and some sage like advice on changes? You have a wicked high karma rating, and I am totally up for paying if it shortens the time to learn and yields a higher quality project.
2  Using Arduino / General Electronics / Re: schematic review, bare bones + 3v + nrfl01 + usb power on: January 02, 2013, 11:44:54 am
thanks db2db. The benefits seem to outweigh the 10cents it'll cost to do it, so I'll definitely add that in.
3  Using Arduino / General Electronics / Re: schematic review, bare bones + 3v + nrfl01 + usb power on: January 02, 2013, 11:41:21 am
its just a badly made pro to area. I'm just going to buy blank atmels, bootload them,  and populate my homemade boards. the proto area i made should hold a mini breadboard perfectly, and gives me room to solder the sensors i'm using directly to the board.

I've got a half dozen sensors around the house currently using the nrf24l01+ transceiver that are measuring various things, but they are on breadboards and my cats keep finding ways to mess things up. So I decided it's finally time to level up and make my own arduino clone with wireless communication built in. Once I get this working, I'm not going to buy any more arduinos from anyone until wireless is standard -and the price is the same <$30. I know about nanode and jeenode, but again, its also about price. I keep seeing evolutions in arduino design, but i think they are all missing the mark. most people don't need more power (and there's now a ton of options like raspberry pi if they do), but connectivity can empower our devices the same way it has our lives, so i have come to believe wireless transceivers should be standard, and the cost should be the same. I dunno, maybe if this board is decent and useful I'll do a kickstarter or something. i'll definitely post the eagle files, after i get a batch that works.

Now that i think about it, I  could connect the pins directly to the left section of the proto area and put the power and ground on the right or middle. Think i should do that instead? Actually, the middle gap is just wasted space, isn't it. huh. thanks for the comment. i'm going to put some more effort into that area.
4  Using Arduino / General Electronics / Re: schematic review, bare bones + 3v + nrfl01 + usb power on: January 01, 2013, 11:21:48 pm
I didn;t know what you mean by decoupling, so I looked it up. Did you mean this : http://electronics.stackexchange.com/questions/2272/what-is-a-decoupling-capacitor-and-how-do-i-know-if-i-need-one which is basically a .1uf capacitor between the arduino vcc and ground to reduce noise?

If so, there are two pin pairs of vcc and grnd, do i do it on both? looks like pins 7+8, and 20+22.

What did you mean by .1 on our of reg?

Your help is greatly appreciated.
5  Using Arduino / General Electronics / Re: schematic review, bare bones + 3v + nrfl01 + usb power on: January 01, 2013, 05:20:31 pm
Ya know, I don't know. Because you asked I went and looked at the reference schematic for the uno ( http://arduino.cc/en/uploads/Main/Arduino_Uno_Rev3-schematic.pdf ) and found a section on the right that i overlooked. They seem to have it connected to ground via  capacitor, which i think would do nothing until you supplied a voltage, so I think leaving it floating is fine.

on this breadboard version they pull it to vcc? : http://arduino.cc/en/Main/Standalone
on this one they do nothing : http://arduino.cc/en/Tutorial/ArduinoToBreadboard

They are both from the arduino website, and it looks like the only difference is the one that connects to vcc also has the ftdi programmer - which conflicts with the schematic - and means there are 3 variations from the same source, so i'm going with the response of..... yes?
6  Using Arduino / Project Guidance / Re: Arduino program dynamically obtains variables from PC ? on: January 01, 2013, 04:16:14 pm
here's a few tutorials to get you started :

http://forums.trossenrobotics.com/tutorials/how-to-diy-128/complete-control-of-an-arduino-via-serial-3300/
http://luckylarry.co.uk/arduino-projects/using-processing-to-send-values-to-arduino/
7  Using Arduino / Project Guidance / Re: radio module.. on: January 01, 2013, 04:08:16 pm
Here's a tutorial I found that looks pretty straight forward.

http://www.doctormonk.com/2012/03/tea5767-fm-radio-breakout-board-for.html

anytime I get a new widget, i just search for "arduino" + widget name. In your case, "arduino tea5767" gives tutorials a plenty, even a library on github.
8  Using Arduino / General Electronics / schematic review, bare bones + 3v + nrfl01 + usb power on: January 01, 2013, 03:58:39 pm
This is my first pcb attempt in eagle, and I was wondering if someone would mind taking a quick look and letting me know if i've made some bone headed mistakes before I take a leap of faith and get a batch made.





I sincerely appreciate the assistance.
9  Development / Other Hardware Development / barebones leonardo pcb on: January 01, 2013, 03:33:46 pm
Hi, I'm making my second venture in to custom pcbs, and I'm trying to make versions of a really bare bones surface mount arduino using the ATmega32u4 (leonardo) and I'm basing it on the adafruit style arduino micro http://arduino.cc/en/Main/ArduinoBoardMicro. Since I still l want to program this smd chip, the usb is not optional, which complicates things for my use a puts my brain in a loop of questions.

I plan on maintaining this post with eagle files and such, so I'll list my project goals first, and my questions below the large line of dashes.

Goals.
1) several versions, starting with the simplest, cheapest 2 layer bare bones + usb programming.
1) I'd like to only allow power via the usb connector, removing the power selector and the VIN option.
2) a 3v only version and a 5v only version - 3v is priority.
3) minimal components - no niceties like current overload fuses, or anything like that.
4) 2 layer, parts all on one side - which will be on bottom so the top can have the i/o  pins and a mini breadboard.
5) version with nrf24l01+ on board with chip or pcb antenna - seriously all arduinos should have built in wireless, or ethernet by now.
6) version configured to mount led matrix - possibly rgb matrix
7) version with embedded ethernet, following this : http://www.instructables.com/id/A-credit-card-sized-Ethernet-Arduino-compatable-co/

---------------------------------------------------------------------------------------------------------------------------

QUESTIONS: (they all reference this schematic of the arduino micro : http://arduino.cc/en/uploads/Main/arduino-micro-schematic.pdf

1) considering the 3v only version, and usb communication. Is that going to work? Can I go from usb src to a 3v regulator to the arduino and still have the usb data pins connected directly to the arduino at 5v? removing a auto selector and 5v reg might cut about 25% off the complexity and bom, but if i have to use logic converters to support 3v, i'll just stick with 5v only version, but it'll kinda suck.

2) I read that there are current protection circuits and noticed a bunch of extra "stuff" on the left side of atmega. Unfortunately, I have no idea what they do. Anyone care to share some insight on what is easily removable?

3) concerning making a rgb led matrix mountable version. the matrix needs 24 pins.the atmel spec list 26 configurable i/o pins, arduino pulls out 20. what 4 pins would you suggest are able to be hijacked for my purposes? i could add an i/o expander, but it takes me in the opposite direction i'd like to go.

4) I was thinking of removing the usb communication and just keeping the usb power, and programming it via isp only. i've done this with tiny45s and a 168 using the arduino ide, but i don't know where to get the library files or settings to do this with a 32u4. Would someone point me in the right direction? Learning to do this for any chip would be pretty awesome, but i'll take the fish or the fishing lessons.


Any and all comments are very much appreciated.
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