deskthority

Teensy 2.0 is still the default go-to board for many projects - it's the smallest of the breakout boards, and a good reliable choice. Needless to say, it's the one the rest are compared with.

But different projects have different requirements, and sometimes the Teensy just isn't quite right for them.

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To build the smallest converter I could, I used a dongle made by TIAO:
The soldering was difficult and fiddly, and one of the dongles I got didn't work, but I did get one working very nicely in the end

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Lately the Arduino Leonardo and clones have become highly available, and while they're comparatively large, they are easy to plug bits into and experiment with.
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Today I spotted a breakout titled "Leonardo Nano Pro Mini ATmega32U4 ..." on eBay
This one looks quite nice - a little bigger than a Teensy, but it has a couple of nice features. The pinout is more regular, with the pins for each port mostly grouped together, so it would be nicer to use for a replacement keyboard controller. Also, it has mounting holes, so it should be easier to secure inside a project box, without having to first solder it to some stripboard.
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Please post more!

(Please try to upload pictures here rather than link, and if the item is on ebay please try to give enough identification that it might be found again after the listing has expired. Thanks!)

There was an official leonardo mini introduced a few days ago. I don't know if it's the same layout and dimensions of the one you posted.



More info about it can be found on the arduino-site.

http://arduino.cc/en/Main/ArduinoBoardMicro

I hadn't heard about that one... how timely this thread is!!

Interesting board - the dimensions look similar to the one I posted, and it has mounting holes. The pinout is different, but that's good - more choice for us!

I get the feeling that with Leonardo, and now the micro, we'll get quite a few clones and near-clones coming out.

edit: Couldn't find a pinout showing the AVR pin designations, so I knocked one up (beware possible errors!)...
PB0, PD5 and PC7 have LEDs attached to them, which could limit their use for other purposes. Or could be useful!

very interesting ! This subject deserve a place in the wiki

I use this board recently apart from Teensy. Its size is same width(600mil?) but 4pins longer than Teensy and I like its cleaner pinouts of PORTB and D. I think it is available only in Japan unfortunately.
http://strawberry-linux.com/catalog/items?code=25001


I like this chip but its price in the market is a bummer. Tow days ago, I had to buy 25 chips from digikey to get better discount, 25 is too much even for my whole life! lol
It seems ATMega32U4 price still will keep high position for a while
http://octopart.com/blog/archives/2012/ ... al-pricing

http://shrimping.it/blog/
http://wolfpaulus.com/journal/embedded/minimalarduino
https://estore.ti.com/Stellaris-LaunchPad.aspx
https://estore.ti.com/MSP-EXP430G2-MSP4 ... P2031.aspx

Heh, I was thinking of alternatives that still used the '32U4, otherwise it probably gets too much for one thread!

BTW: Did somebody find a clone with through-holes just between the USB socket and controller to solder an USB cable to the board?

My local hackerspace is also working on a Dev Board using the ATmega32U4. They will be used on some projects we are planning, and I might be able to get one for my "Raspberry Pi inside an IBM Terminal Board"-project.

JBert wrote:BTW: Did somebody find a clone with through-holes just between the USB socket and controller to solder an USB cable to the board?

There's one by MattairTech that has the USB D- and D+ connections broken out: the MT-DB-U4. Currently also on eBay as "ATmega32U4 Atmel USB AVR Arduino compat. DAQ development board data acquisition".

Looks pretty good, and a good price Teensy++ sized, same as a 40-pin DIL.

I used a PS3 jailbreak dongle for an XT converter once. Under $10 for an AT90USB162 with HWB button and two LEDs. Soldering wires onto TQFP pins is not my idea of fun, though.

this is the same controller that kmac uses

So, does anybody here have any experiences with using an Arduino Micro? They're very readily available now, and avoiding the international shipping makes them cheaper than Teensys (with pins).

Adafruit has its own 32u4 breakout board: https://www.adafruit.com/products/296
A nice writeup 'why not teensy' from Ada: http://www.ladyada.net/products/atmega32u4breakout/

Olimex LPC-P1343 is cheaper than teensy (~$17) and is also interesting, but it's LPC1343 Cortex-M3 32 kB Flash, 8kB SRAM. Downsides:

philpirj wrote:Adafruit has its own 32u4 breakout board: https://www.adafruit.com/products/296
A nice writeup 'why not teensy' from Ada: http://www.ladyada.net/products/atmega32u4breakout/

How did we fail to mention that one already?!

The "Leonardo Nano Pro Mini ATmega32U4 ..." on eBay mentioned in the first post appears to be using the adafruit design. Here's the adafruit board's pinout:

Some more teensy alternatives.

NXP LPC1343 based (32-bit Cortex-M3 32 kB FLASH 8 kB SRAM, USB, 42 GPIOs):
http://www.embeddedartists.com/products ... 43_qsb.php 16 EUR


Tiny, comes with examples etc. Is an alternative to Teensy 3.0.
Instructions how to build one http://voltsandbytes.com/lpc1343-breakout-board/


And another interesting one, TI Stellaris based (Cortex M4F 256 KB Flash 32 kB SRAM, USB, 43 GPIOs)
http://www.ti.com/tool/ek-lm4f120xl $13


It's relatively large to be used as is.

All interesting... but not ATmega32U4! Maybe we need another thread for Teensy 3.0 alternatives

Deserves its own topic in wiki along with firmwares. Anyone willing to make a stub?

BTW have a local russian supplier for AT90USB162 (16KB Flash 512B SRAM, USB 22 GPIOs, No I2C) based chip ~$15 http://microsin.ru/content/view/685/44/

Another thread here could be for a low-cost USB+I2C only controllers only and some I2C controlled GPIO extender chips (specifically good for split keyboard designs, but not only).

Forgot to mention XMC4500 Relax Lite Kit (Cortex M4F 3xI2C a lot of GPIOs), debug onboard 10 EUR only
http://www.ehitex.de/cortex-development ... e-kit?c=40

Soarer wrote:

JBert wrote:BTW: Did somebody find a clone with through-holes just between the USB socket and controller to solder an USB cable to the board?

There's one by MattairTech that has the USB D- and D+ connections broken out: the MT-DB-U4. Currently also on eBay as "ATmega32U4 Atmel USB AVR Arduino compat. DAQ development board data acquisition".

Looks pretty good, and a good price :) Teensy++ sized, same as a 40-pin DIL.

The attachment MT-DB-U4_arduino_pinout_660.jpg is no longer available

They also have a similar board for the 32u2. I bought a couple of these already. I like that they unlike the Teensies have external access to all pins, dedicated ISP headers, and a lot more jumper configurations. They lack room for a voltage regulator, but I guess that could just as well be placed on it's own somewhere. They seem to have updated the board layout slightly for the 32u4 board as well. I think I'm going to get a couple of them as well =)

I've found another interesting option I'm going to try in my next project. It's not a breakout board, but a single chip with USB, I2C and 20 pins total, Microchip PIC16F1459. http://www.microchip.com/wwwproducts/De ... e=en556971
Price: $2.20


Pros:
- price
- twice as narrow (300mil vs 700mil) and shorter (10 pins vs 12 pins on longest side) as Teensy 2.0
- has onboard 16MHz quartz capable for USB operation
- has a bootloader for one-click programming via USB http://www.schmalzhaus.com/UBW/ (chip used on that breakout is 4 years old)
- doesn't have USB connector onboard, only pins, so the connector can be anywhere on the board
- enough pins to connect I2C and a 6x7 matrix (42 keys, should be enough for right half of ErgoDox, another part handled with IOmux via I2C)
- PDIP package, easy to solder through holes

Cons:
- not an AVR, tmk_keyboard will not work and other firmwares won't work
- lacks LED and push button, though they can be attached
- less GPIO, 15 (minus one for programming button) vs 20 (minus one used by LED)
- needs couple of capacitors
- less memory (1KB vs 2.5KB RAM, 8KB vs 32KB program memory)

There are a bunch of other choices, for example PIC18F25K50 with 32 flash/2RAM/ 28PDIP300mil package, more than enough GPIO, slightly longer than Teensy (by 2 pins), $2.66.

Definitely worth to look at. Should be around $5 total with usb connector, capacitors, push button and resistor vs $16 for Teensy. You can include a PDIP socket and it will be $6 vs $19.

anyone seen this http://www.kickstarter.com/projects/160 ... atible-boa
not enough pins though (that's pretty much where my knowledge ends^^)

It could be enough if the pins can handle I2C, just need to add a few IO expander. But you then loose the space this stuff can save.

Interesting though.

http://www.geocities.jp/arduino_diecimi ... ex_en.html
single-chip 300mil PDIP28 AVR with all goodies of Teensy and more. + nice design

How is that PCB mounted to the chip? It looks flimsy, unless properly secured the USB connector could rip the whole thing apart when handled improperly.

That's Teensy... as made by Sinclair!

No hardware USB on any of those DIP AVRs though

I like Mega328 or 168 with V-USB and USBaspLoader for prototyping on breadboard particularly. It really works well in terms of program via USB, like Teensy or ATMega32U4.

I mentioned PIC18F25K50 already, the one in PDIP package, and here comes breakout board:

http://dev.odroid.com/projects/pic18f45k50/
http://www.hardkernel.com/renewal_2011/ ... 5390529643
$15 for the board, plus $25 for shipping (Korea)
I would buy this one just to try out PIC18.

I received this link from TI.com http://www.ti.com/product/tca8424?DCMP= ... 424-bti-en. It's a keyboard chip transmitting HID over I2C. It seems nice, but I'm not sure it provides a great improvement vs using teensy GPIO.

It is for integrated keyboard of notebook which uses internal i2c instead of USB bus. It is not for DIY use but still interesting.

I'm recently working on board design for keyboard converter or prototype controller as my first PCB with kicad. This is not small as Teensy, but has mini DIN socket and mini/micro USB socket. It being processed with cheap Chinese manufacturer. I hope I didn't make big misktake on this.