Moteino Leo: Atmega32u4 based Moteino


I’ve been working on a Atmega32u4 version of Moteino, one that would allow USB connectivity and inherently no need for a FTDI adapter. This is basically an Arduino Leonardo clone that adds the RFM12B radio and a SPI FLASH footprint for optional data logging ability. I meant to post the details of this for several weeks but never found the time for a write-up.


I now have a working prototype. I have some small changes in mind but it is functional as is. For this version I had to make a small change to the Caterina bootloader to make the onboard LED work properly. By default the Caterina bootloader assumes the LED is sinking current from VDD to the output pin, my version was sinking current from the output pin to GND. This is one of my planned changes, to allow the default Caterina to work with MoteinoLeo out of the box. Wireless programming will not yet work on Moteino Leo and I don’t know when I will find the time to customize Caterina for this purpose. From all I know Caterina takes about ~4kb of bootloader space which might be too much to add ~500 bytes of extra code. I will have to experiment with this sometime in the future if people actually have an interest in this.

Fun fact: using the same DIY metal stencil technique I was able to make a stencil, apply the paste with it and make this Moteino Leo prototype.

 MoteinoLeo_R1_stencil DSC02551_banner DSC02552

Eagle files and bootloader source are published in GitHub.

21 thoughts on “Moteino Leo: Atmega32u4 based Moteino

    • Haven’t really spent the time and resources to start producing these … I would consider that if there is high enough demand. Otherwise you may produce the PCBs from the eagle files and do the soldering yourself, everything is open source.

      • I would really love to get a few of those leo’s, mostly because im only familiar with arduino uno programming with USB,and all that FTDI stuff gets me confused a lot lol.

        And Cheers for the great project so far 🙂

  1. WOW, I love the onchip USB. I’m like Thomas, I don’t have any experience with FTDI. I’ve been looking really hard at a wireless sensor/control network.

    Any thoughts on the RFM22B module? Will it work? Can I mix the RFM12 with a RFM22 module?

    Thanks for the great product.

    • A production version is being manufactured. Will be a few weeks before I have it available, if nothing goes wrong…
      RFM22 is nice but I heard it’s being phased out. They have other radios that are newer/better and have more features like built in CRC/encryption, packet handling etc. Not sure if you can mix RFM22 but my first impression is that it would be difficult. Also I only found 1 library for rfm22 that was usable and it had a large RAM/ROM footprint…so not sure it’s worth to bother with the rfm22.

  2. I’ll take two.. Is there a notification service or Can i pre order??

  3. Wow! Would love to get a few of the usb ones. I think that it is time that people include usb in everything, rather than have to use an adapter… Good work, as usual!

  4. Mounting holes, at least two of them, would be nice. Without them you can use the moteino easily on a breadboard, but if you want to put it in an enclosure for a real project then your options are more limited.

    • Unfortunately mounting holes are very bulky compared to the size of this board. Most people won’t need that but there are other ways you can mount PCBs inside an enclosure.

  5. So is the USB just for programming or can it be used for data bridging? Connect to rPi logging the data of the other motenios. Mind u it would be better investment going 1 ftdi to program many basic versions. Idea can we piggy back on the USB circuit to program another basic monteino?

    • Power, programming, and can emulate serial port and other usb devices (mouse, keyboard etc). See the Moteino page and Arduino Leonardo for more details.

  6. v interested in these. I have been enjoying the leonardo – Ive been making a HID device for controlling a specific program, using rotaty encoders and buttons. It would be great if I could make it wireless though – but Im not sure how to go about it. Does your board have wireless-ness built in?

  7. Hi Felix,

    Do you know if you will have code for the RFM69HW for the Leo and any pin out instructions or will the HFM69 library work with the Leo with minor modifications?


    • Leo was only designed for RFM12B. I guess you could connect an RFM69 to it with hookup wire, then you could use the RFM69 lib.
      Leo is now retired and replaced by Moteino-R4-USB which can take either a RFM12B or RFM69 transceiver.

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