keytee -- Controller breakout board for small keyboards

[Ratfink]

For anyone interested in building one, I ordered six boards from OSH Park and it cost me all of 5.70$ shipping included (I'm located in the US, which may effect that). I'll have to order components and whatnot but that seems like a very reasonable price for PCBs. I love the design, and am looking forward to doing hand wired projects without worrying about excessively thick cases or finding somewhere to jam a teensy.

So you should be able to make single-digit batches with components from reputable suppliers for less than 5 [$€£] apiece, ignoring labour and tools. The 1.6 mm thickness OSH Park seems to do exclusively(?) may look a bit overweight, though.

One can still get a couple of free PCBs from me; these would be 0.6 mm thick.

OSH Park can make 0.8 mm thick boards with 2 oz copper, but it takes longer. I'm currently playing that waiting game for a keyboard-unrelated project.

[rominronin]

Sounds great.

But can anyone find a producer who can build the components on board? I wonder how low we can get it, especially if there's a bulk order...

[pomk]

From PCBway it would be around 250 USD plus the price of components for 100 assembled boards. It looks like the components would be around 4,5 USD per board, so a total of 7 USD per piece assembled seems like a target that could be hit. http://www.pcbway.com/orderonline.aspx

What I really don't get is why one would choose this over the Elf board which matt3o is producing? I mean this looks great and it's well miniaturized, but I just don't get the benefit this has. I guess if you don't like usb sockets on a keyboard this will be ever so slightly cheaper.

[CountZero]

From PCBway it would be around 250 USD plus the price of components for 100 assembled boards. It looks like the components would be around 4,5 USD per board, so a total of 7 USD per piece assembled seems like a target that could be hit. http://www.pcbway.com/orderonline.aspx

What I really don't get is why one would choose this over the Elf board which matt3o is producing? I mean this looks great and it's well miniaturized, but I just don't get the benefit this has. I guess if you don't like usb sockets on a keyboard this will be ever so slightly cheaper.

Price estimates seem to be 7$/keytee, 18$/elf board.

I don't think the two are in direct competition, with the keytee you get a barebones controller at a barebones price, the ELF board is expensive and feature rich. Keytee does have the current advantage in the availability department. To the best of my knowledge I cannot buy or build and ELF board but everything I need to build a keytee is a couple clicks away.

[pomk]

The elf boards production cost estimate is about 10 USD, with the main difference coming from the price of the usb socket. The board carries the open hw logo, meaning that the files will be released after the initial batch afaik.

[Sythe]

I kind of see them as different markets.
Keytee is ultra low cost for limited purposes(especially when Trebb was willing to send me a couple of boards).
Also requires more user knowledge and is harder to work with.
Total cost to me is going to be <US$4 ea for 5pcs.
The elf board is a catch all board, going to be cheap, but not that cheap. Got a lot more feature and a lot more user friendly. Just the component cost on the elf board is 2x higher.

I don't think that the talk of group buying for this is very feasible though unless you were looking at 1k+, the low cost and few components make it so that small runs are cost prohibitive compared to expectation due to pick&place/tooling costs.
If you bought in bulk though, total cost would probably be <US$5.
At low volume your tooling/pick&place cost will be same or more than the cost of production per board.

[trebb]

From PCBway it would be around 250 USD plus the price of components for 100 assembled boards. It looks like the components would be around 4,5 USD per board, so a total of 7 USD per piece assembled seems like a target that could be hit. http://www.pcbway.com/orderonline.aspx
What I really don't get is why one would choose this over the Elf board which matt3o is producing? I mean this looks great and it's well miniaturized, but I just don't get the benefit this has. I guess if you don't like usb sockets on a keyboard this will be ever so slightly cheaper.

I like my keyboards as thin as possible. Something like this

Spoiler:

could be handwired with a keytee, but not with an Elf board or any other breakout board I'm aware of.

To be fair, the Elf board would come with a bootloader while the keytee requires a USBasp programmer to make it accessible via USB. The Elf board also has a lot more usable pins.

[trebb]

Keytee is now identified by its own, unique set of USB IDs, issued by http://pid.codes:

Vendor ID = 0x1209
Product ID = 0xE4EE

[Ratfink]

To be fair, the Elf board would come with a bootloader while the keytee requires a USBasp programmer to make it accessible via USB.

Really? I thought ATMEGA32U2 has a DFU bootloader built-in. In fact, I'm sure of it—I didn't need an AVR programmer to flash the firmware on my xwhatsit controller.

[trebb]

To be fair, the Elf board would come with a bootloader while the keytee requires a USBasp programmer to make it accessible via USB.

Really? I thought ATMEGA32U2 has a DFU bootloader built-in. In fact, I'm sure of it—I didn't need an AVR programmer to flash the firmware on my xwhatsit controller.

The ATMEGA32U4 datasheet contains a footnote saying "These parts are shipped with no USB bootloader pre-programmed", referring to the QFN package. I couldn't find anything like this in the ATMEGA32U2 datasheet, but it seems to be this way nonetheless. Anyway, you need a programmer to modify the fuses (I believe).

[pomk]

I admit that it is hard to beat that design in thickness if you are going as far as filing the switch leads flat on the PCB
The Elf board is only just lower than the switch leads on Cherry MX.

One could make a variant of the keytee with the same microcontroller as is used in the Elf board and get it to be even cheaper and not require an external programmer.

[CountZero]

I admit that it is hard to beat that design in thickness if you are going as far as filing the switch leads flat on the PCB
The Elf board is only just lower than the switch leads on Cherry MX.

One could make a variant of the keytee with the same microcontroller as is used in the Elf board and get it to be even cheaper and not require an external programmer.

Doesn't that require one to invent the ELF board ? If your goal is to build a keyboard going with the established option is going to get you up and running faster. Once the ELF board has been established and develops a similar ecosystem of firmware and support I'm sure we will see more projects that use the same microcontroller.

[trebb]

One could make a variant of the keytee with the same microcontroller as is used in the Elf board and get it to be even cheaper [...]

Really? Comparing the respective 5x5 mm packages at mouser, I get (Qty 10)


KL27Z256, QFN-32: 3.34 €
KL27Z256, MAPBGA-64: 3.65 €
ATMEGA32U2-MU, QFN-32 + crystal: (2.57 + 0.28) €

(Not sure I picked the correct Elf board MCU; is there a place where one could follow development of the Elf board?)

[Sythe]

The elf board ic is more expensive than the atmel/microchip alternative but i was able to find it for like US$2.28 at +100pcs which isn't awful.
If cost was the largest motivating factor going into the elf board, they chose the wrong chip.

The forum thread would be best way to follow I guess? It's close to production imo.

[rominronin]

A link to the Elf board thread for those who are wondering: workshop-f7/can-we-design-the-teensy-al ... 13662.html

[jball]

Seeed Studio Fusion are Ok for hobby boards. Last time I used them for pcb fabrication they charged $9.9 for 10pcs 10x10cm boards, not including postage fee. Quality is excellent from each.

[pomk]

One could make a variant of the keytee with the same microcontroller as is used in the Elf board and get it to be even cheaper [...]

Really? Comparing the respective 5x5 mm packages at mouser, I get (Qty 10)


KL27Z256, QFN-32: 3.34 €
KL27Z256, MAPBGA-64: 3.65 €
ATMEGA32U2-MU, QFN-32 + crystal: (2.57 + 0.28) €

(Not sure I picked the correct Elf board MCU; is there a place where one could follow development of the Elf board?)

Ah, I somehow thought that this was using 32U4. My bad. At least on digikey kl27 would have been cheaper than it even without the added cost of the crystal.

[nall]

Was getting ready to order some components, and wanted to confirm: there's no C2, right?

[trebb]

Was getting ready to order some components, and wanted to confirm: there's no C2, right?

That's correct, and your PCB is on its way.

[2ZQ]

If you have any available I could use, I would be extremely grateful. Teensy that I ordered from a reputable vendor sent me a fake brick and is not honoring my return claim. So bummed that I didn't get to finish this build on my only day off!
Let me know what to do if you still have!

[trebb]

If you have any available I could use, I would be extremely grateful. [...] Let me know what to do if you still have!

Just give me your address and the number of PCBs you want, and wait for the letter I'll send you.

[bpiphany]

To be fair, the Elf board would come with a bootloader while the keytee requires a USBasp programmer to make it accessible via USB.

Really? I thought ATMEGA32U2 has a DFU bootloader built-in. In fact, I'm sure of it—I didn't need an AVR programmer to flash the firmware on my xwhatsit controller.

The ATMEGA32U4 datasheet contains a footnote saying "These parts are shipped with no USB bootloader pre-programmed", referring to the QFN package. I couldn't find anything like this in the ATMEGA32U2 datasheet, but it seems to be this way nonetheless. Anyway, you need a programmer to modify the fuses (I believe).

That footnote actually contradicts the description on page 1

Parts using external XTAL clock are pre-programed with a default USB bootloader

I wonder in which direction they got it wrong. Once I had to order the RC-AU version due to the normal TQFP package being out of stock. Then I of course had to use a programmer to change the fuses to use an external clock, and also flash a bootloader. (I don't know for sure if the fuses can be changed without erasing the flash).

Anyway it would make more sense if the description text is correct. There would be little idea to ship the RC versions with a bootloader, since the mega isn't specified to run USB on the internal clock source. I would think they put all the footnotes on the wrong line, and they were really supposed to go on the ATmega32U4RC-AU.

And you shouldn't need to change the fuses on a factory fresh ATmega32U4. So really you should be able to use them out of the box =)



Nice looking project by the way ::thumb::

[trebb]

The ATMEGA32U4 datasheet contains a footnote saying "These parts are shipped with no USB bootloader pre-programmed", referring to the QFN package. I couldn't find anything like this in the ATMEGA32U2 datasheet, but it seems to be this way nonetheless. Anyway, you need a programmer to modify the fuses (I believe).

That footnote actually contradicts the description on page 1

Parts using external XTAL clock are pre-programed with a default USB bootloader

I wonder in which direction they got it wrong. Once I had to order the RC-AU version due to the normal TQFP package being out of stock. Then I of course had to use a programmer to change the fuses to use an external clock, and also flash a bootloader. (I don't know for sure if the fuses can be changed without erasing the flash).

Anyway it would make more sense if the description text is correct. There would be little idea to ship the RC versions with a bootloader, since the mega isn't specified to run USB on the internal clock source. I would think they put all the footnotes on the wrong line, and they were really supposed to go on the ATmega32U4RC-AU.

And you shouldn't need to change the fuses on a factory fresh ATmega32U4. So really you should be able to use them out of the box =)

It would be nice if someone (including me) could confirm whether the QFN ("-MU") variants of pristine

• ATmega32U4-MU and
• ATmega32U2-MU (as used in this project)

MCUs announce themselves as some sort of USB device.

[bpiphany]

I'm totally sure I didn't need to flash any bootloader when I built these They come with Atmel's loader. As does the TQFP ATmega32u2. Factory fresh they jump to the bootloader on power up. Technically I suppose they are programmed with a firmware that simply does a software jmp to it. I haven't actually tested what an erased chip does though, perhaps it skips along until it finds the bootloader. Or it just does nothing... I need to check =D

[2ZQ]

Just wanted to thank you again! Mine arrived yesterday, was just able to open them before I left for work!!
Can't wait to start fiddling around with the placement options now, it is so much smaller than I imagined, you really are amazing! Will send you some goodies in return next week.

[ideus]

If you offer full kits in a group buy, count me in. Being outside ConUS makes sourcing stand alone components unfeasible, cost-wise.

[2ZQ]

If you offer full kits in a group buy, count me in. Being outside ConUS makes sourcing stand alone components unfeasible, cost-wise.

Maybe we could geoup buy components? Also outside the states but designer is in Europe and I am definitely interested in more of these, but only trust myself for soldering (and subsequent troubleshooting).

[Sythe]

So close to finishing my first board with one of these and got device descriptor failed error no matter what I do.
All troubleshooting I have done hasn't cleared up what my issue actually is. Not sure if its the board itself, or my USB cable being bad.
Nothing obvious showing up.

Ideas?

I had no issues when flashing bootloader using AVRISP, only when I connect via USB afterwards.

Going to have to swap in another of these pcbs I got and see how it goes.

[trebb]

So close to finishing my first board with one of these and got device descriptor failed error no matter what I do.
All troubleshooting I have done hasn't cleared up what my issue actually is. Not sure if its the board itself, or my USB cable being bad.
Nothing obvious showing up.

Ideas?

I had no issues when flashing bootloader using AVRISP, only when I connect via USB afterwards.

Going to have to swap in another of these pcbs I got and see how it goes.

You don't mention the fuses; have you set them correctly?

What kind of bootloader do you use? You could try and use none, flashing the keyboard firmware .hex file in its place.

In case you're (or anybody is) running out of PCBs, just let me know. I've got still lots of them.

[Sythe]

Fuses are done as well.
I tried your bootloader that was provided and another that I found, but same problem.
I might try the firmware flashing and see what happens.

I have loaded the components onto 5 boards so far and this is the first one I have wired up to test. After the bootloader flashed no issue I got a little bold and forged ahead assuming everything was good to go, lol.
I think I will wire up another and see what happens. Currently feels like the easiest way to troubleshoot this problem is to use another board and then I can hopefully rule out certain things to narrow down possible issues.