Echo R1 - new STM32-based open hardware player

[amachronic]

Last year, I started working on designing an STM32-based board with the goal of putting Rockbox onto it, which I've previously mentioned on these forums. I'm happy to announce that design is now complete! I've ordered the boards from JLCPCB, assembled a prototype, and started porting Rockbox to it. I'll be sending the patches soon. The hardware design is open source, under the CERN-OHL-S v2 license, so all the schematics and documentation are freely available.

It's called the Echo R1, and the case design is somewhat inspired by the iPod 6G and the Sansa Clip players. This is my prototype board, displaying the RB logo (which is pretty much all it can do right now):



Here's a render of the case mockup in FreeCAD -- it's just for show and to get an idea of how the final product should look. I 3D-printed a simpler version of this mockup to get a feel for the controls before committing to the PCB, but mostly neglected the mechanical design in favor of getting the PCB out the door faster (which I'm sure I'll regret when I start doing the real case model ). The dimensions are 60x100x15mm, approximately the same size as the iPod 6G but somewhat thicker. My goal was "small but not too small", make it easy to operate with one hand, and in theory ambidextrous (so, no weird asymmetrical buttons).



Those interested can check out the KiCAD schematics themselves, but here is the board in KiCAD's 3D view:




My intention was to start with a simple, conservative design, nothing flashy or fancy, just a good solid music player. But it's still pretty complicated to get the specs I wanted -- having some sort of fast external RAM was non-negotiable since almost all Rockbox players have at least 8 MiB, and I wanted to be able to run RB without sacrificing any features. The CPU is an STM32H743, which is an ARM Cortex-M7 processor running at 480 MHz. There's 32 MiB of SDRAM. The LCD is 2.3 inches, 320x240 px, with both SPI and 18-bit parallel bus interfaces. The audio codec is the Texas Instruments TLV320AIC3104, which supports sample rates up to 96 KHz, and is hooked up to independent headphone and line out ports. There are a total of 12 buttons (4-way D-pad; 6 face buttons; 2 volume buttons) plus a power button and hold switch. The power button can also be used as a general purpose button. There is an SD card slot for storage, but no internal memory beyond the STM32's internal flash, which is only 2 MB and isn't really suitable for general purpose data storage. Lastly, it supports high-speed USB 2.0, with a USB-C port.

The RB port is still in the very early stages. I've only tested the LCD and to a limited extent the SDRAM. The only problem I've found so far is the backlight, which can't be turned off (the result of a stupid last minute change, which I didn't think through properly).

If anyone is interested in acquiring one of these devices to play with, I'm happy to do a small batch order of some assembled boards (with LCDs) and send out kits to people.

Schematics and some documentation can be found on Github: https://github.com/amachronic/echoplayer

[Milardo]

Hi,

Is this the size of a gameboy color?

Looks interesting, just looking for another lower priced music player for rockbox, of which for new, there aren't any at the moment.

What would it cost if produced for consumers?

[7o9]

That looks very nice and very real.

Any chance you can also share a picture of the other side?

Using a replaceable battery is interesting.

Sign me up for a rev2 version with the first bugs ironed out!

[amachronic]

Hi,

Is this the size of a gameboy color?

Looks interesting, just looking for another lower priced music player for rockbox, of which for new, there aren't any at the moment.

What would it cost if produced for consumers?

It's 60mm wide x 100mm tall x approx 15mm deep, so it's decently smaller than the gameboy color -- Wikipedia tells me the GBC is 78x133x27mm.

As for price, I can't give a good answer at the moment because there are still parts of the equation I'm missing, like PCB assembly or the case. It also depends on volume and how it's sold (which depends partly on volume), eg. to sell it like a normal commercial product, there are extra costs which would need to be amortized over all the sales. For instance you need EMC testing, UL/CE markings, USB VID/PID... I haven't done a huge amount of research into this.

[Oktan]

Hell yeah! Would it be possible to add a lanyard loop to the case, like the Eros Q has? Or would that cause space issues with the board?

[amachronic]

I don't think it would cause any real difficulties, but the current PCB layout wasn't designed to accommodate it -- all the corners are occupied and it's supposed to be centered in the case, so there's no obvious place to put a lanyard. I guess you could punch a hole or two in the sides of the case and then fit a lanyard above/below the PCB but you'd have to open the case to tie/untie it.

Next time I reroute the board I'll keep your idea in mind.

[Oktan]

Aww that's really cool of you. I like that feature, and given ongoing 00s nostalgia there's likely a demand for being able to use phone charms.

[dconrad]

That is a really good looking design, I like it! And of anybody, you're sure to get the details right I think. I would definitely be interested in one if you get the kinks worked out!

One idea for the case (maybe you've already thought of this): Might be cool to have the battery model number engraved on the battery door so in 5 years when it wears out you don't need to go "okay what was the battery model again???"

[Oktan]

One idea for the case (maybe you've already thought of this): Might be cool to have the battery model number engraved on the battery door so in 5 years when it wears out you don't need to go "okay what was the battery model again???"

I mean, as long as you have the old battery, that shouldn't be a problem. But from what I understand there won't be a battery door, you charge it when it's in the device, and you have to open the device to change it out. The easiest way to integrate this on the device would be to have it printed on the circuit board.

[bigpilot]

Really neat project! I just purchased a Chinese music player and although the hardware is decent the software sucks and I can't find an update anywhere. That's why I'm very interested in an open-source player. Or one which supports Rockbox.

But very few never Chinese MP3 players have Rockbox support.