Small Arduino Replacement?

I don't need it to be breadboard friendly, I just need it for a final version.

Re...

software he wrote to upload the boot loader

For the innocent... is there an idiot's guide to how we do this somewhere?

Apart from the "coolness" factor of being slightly smaller than the RBBB... Oh! And the built in USB circuits, if you are going to be keeping it connected to a "big" PC (in which case why is being small good?) I don't see how this "beats" the less expensive (if you discount just a LITTLE of your time, for a quick and easy solder-up... which you can offset against the "upload the boot loader" chore) RBBB?

(Apologies if it seems I'm engaging in a "Mac vs PC" flame war... just interested in knowing the pros and cons. Yes, of course, I'm always delighted to learn that there's another alternative out there!)

tkbyd:
For the innocent... is there an idiot's guide to how we do this somewhere?

Yup:
http://www.pjrc.com/teensy/td_download.html

I own MANY of Paul's BBBs and RBBBs. We've talked at reasonable length about how much I use the BBB in particular. It's the board in my best selling personal design, in fact.

That said, I use a Teensy when:

  • Space is a concern, but 5v power is easy to find.
  • I'm making something portable / wearable.
  • I need to update the sketch regularly. The USB transfer is LIGHTNING fast, uploading most sketches before I notice it's started.
  • I'm sending something out in the world that will likely need a firmware update and don't want to sell the FTDI adapter (a hidden cost of any board without USB)
  • I'm writing the code from scratch and can work around the (very few, and soon to be none because of the Leonardo) quirks of writing for the ATMEGA32U4

I use a BBB (or RBBB) when:

  • I want the pins broken out along one edge for easy stripboard prototyping (BBB).
  • I only have 6-36v power handy and need to power my device with that. I use these: http://www.murata-ps.com/data/meters/dms-78xxsr.pdf LOVE THEM.
  • I don't want an LED AT ALL on the board.
  • I am wanting the likely placebo like effect of throwing that 15uH inductor on the board because I'm doing ADC reads and think it might help. (BBB)
  • I think I will want the ability to quickly change out the chip because I'm attempting something that I secretly feel is unwise and will smoke a port.

Paul and Robin (Teensy folks) are ABSURDLY fast at shipping and when you get the Teensy, it comes with a great glossy card with one side showing you the basic AVR pin assignments and the other showing the Teensyduino port assignments.

Final bit is that when it comes to being breadboard friendly, the Teensy is still 98% fantastic because only +5, GND,RST and A11 are on the end of the board. MOST people can make do with 10 ADCs, will be happy to use the reset button on the top of the board while breadboarding, and +5 and GND are also to be found on the sides of the board.

If you're just after standalone small (no USB), there's the Mini-uino PCBs I made up also, see the link in my signature, for a bare minimum arduino clone.
No USB, no regulator, just the '328, crystal, caps, reset pullup resistor, and the IO pins with a ground for each one.

here's a picture of one of Crossroads mini-uino boards compared to a regular uno. You do have to assemble it yourself, but it's only a few components. (click for fullsize)

That's odd, they look so much smaller sitting by themselves on my desk!

it's about 1/3 the size. Seems pretty good to me. Also the mini-uino was sitting at a little bit of an angle, so it does look a little bigger in the photo.

Ummm... so, revealing yet again my capacity to be dim... is the following more or less on target?

If I wanted to become a Teensy-phile, I....

a) "Once and for all", "do some stuff" to improve my basic Arduino development environment, and then, after that....

b) Using a Teensy is pretty much like using a "real" Arduino, an RBBB, etc?

That's not too terrible! <^_^>

I was afraid that the "upload the bootloader" stuff was something I had to do with each new Teensy as it came into use... somewhat along the lines of "formatting a disc".

Oh dear. Now I have to buy a Teensy, and lose a few days playing with ANOTHER "new toy".

Joking aside... always good to have alternatives... thank you for the link to the "how to", and, if you are reading, thank you to whoever wrote it!

(For new people reading this thread... and to check an assumption that doesn't worry me much, but hasn't been covered... And, when "switching" from working with, say, an RBBB to an Teensy, I'd also use "Tools | Board" to tell the development environment, just as I would if, say, switching from an Uno to a Duemilanova?

For small-size and Arduino compatibility, take a look at the Sparkfun ProMini. Programming the ProMini is essentially the same as for the Uno, except that the programming interface can be removed when not needed. They both use the ATmega328 chip.

The Teensy is extremely cool, but I rarely find myself needing the small size and built-in USB.

Here's a rough size comparison between an Uno and a ProMini. The red board is the FTDI USB-to-TTL-serial programming interface:

How much current do RGB leds draw at full brightness? That to me is a real limit and time to think about drivers or not.

a) "Once and for all", "do some stuff" to improve my basic Arduino development environment, and then, after that....
b) Using a Teensy is pretty much like using a "real" Arduino, an RBBB, etc?

Correct, but!

I was afraid that the "upload the bootloader" stuff was something I had to do with each new Teensy as it came into use... somewhat along the lines of "formatting a disc".

This is also TRUE. If I buy 5 Teensys, I need to plug each in and click a button to upload the Arduino bootloader. Once this is done, you don't have to do it again.

I believe the last time I did it, it took ~6 seconds.

Most LEDs are spec'ed for 20mA.
RGB, 20mA per color.

The Teensy is extremely cool, but I rarely find myself needing the small size and built-in USB.

There are many more differences...

• Full speed USB (12 Mps) versus 115200 baud. Transferring data between the board and the PC is much faster. It is even possible for the board to detect when the PC has the port open.
• Hardware USART not used for communicating with the PC making it available for communicating with other devices.
• More PWM pins
• Few more I/O pins
• More analog pins
• Two 16 bit timers instead of one
• Less expensive

And, when "switching" from working with, say, an RBBB to an Teensy, I'd also use "Tools | Board" to tell the development environment, just as I would if, say, switching from an Uno to a Duemilanova?

Yes. As an added bonus, Teensyduino makes the IDE a bit friendlier even when used for non-Teensy boards.

For size reference here are the Arduino variants that I have and a couple of ATTiny boards.

From left to right:

  1. Circuit board for the Femtoduino designed by Fabio Varesano. By far the smallest, but will not work directly with a breadboard. Needs an FTDI adapter.

  2. Teensy 2.0. A little smaller than a Pro mini, more I/O pins, built in USB, and a couple dollars less.

  3. Arduino Pro Mini 3.3V from Sparkfun. Standard Arduino. You need an FTDI adapter. I use this FTDI cable from Sparkfun.

  4. ATTiny13/ATTiny25 board from AllgaierShops. Good for breadboard work, but no Ardunio bootloader so you need to use C compiler and an ISP programmer.

  5. ATTiny2313 board from AllgaierShops. Good for breadboard work, but no Ardunio bootloader so you need to use C compiler and an ISP programmer.

And my Mini-uino boards, 1.3" square, with ICSP pins for downloading bootloader via FTDI Breakout, or Arduino as ISP, or Mdfly programmer.
Ground next to each IO pin aslo.
Need to install ATMega328P-AU, 16 MHz xtal, two 22 pf caps, 3 100nF caps, 10K resistor, header pins to suit your needs.

mini-uino_closeup_small.jpg

For the sake of completeness, we ought to mention the Solarbotics Ardweeny. ($10) The PBC with the support circuits is barely larger than the DIL Atmega, and is soldered to its pins...

http://www.solarbotics.com/products/kardw/

... not that I think it is a GOOD design... but it is kind of fun!

So... anyone want to take on the challenge of doing that with one of the tiny square SMT Atmegas? <^_^>

CrossRoads:
Most LEDs are spec'ed for 20mA.
RGB, 20mA per color.

Yes, 5 RGB leds x 3 elements x 20mA = 300mA.... through the pins, should be a factor.

BTW I like the Teensy but I think I'd pop for the Teensy++. OTOH I have a UNO and breadboards....

Its rare (if at all) that all three colors of the RGB will be on at the same time. Mostly just strobing really fast (6 ms on, 1-2 ms off) between colors. So I don't think that excessive current output with be a problem....

Xyver:
Its rare (if at all) that all three colors of the RGB will be on at the same time. Mostly just strobing really fast (6 ms on, 1-2 ms off) between colors. So I don't think that excessive current output with be a problem....

That should be ok. If more current is needed this shift register rocks http://www.nxp.com/products/automotive/logic/shift_registers/HEF4794B.html after that you'd need some UNL chips or discrete transistors.