Wednesday, December 20, 2017
Bare PCB U2F Security KeyI got one of these keys from Amazon. They are used for 2 factor security with websites like Google and Github.
There are many different styles of these keys. Some look like little USB thumb drives. Others like the Yubico or Feitian are plastic encapsulated. This one is a bare PCB with a physical switch.
The U2F Zero is a single purpose keyboard with one key switch. It uses the USB HID protocol and has an RGB LED. It's also one of the cheapest U2F keys available.
The U2F Zero is an opensource project hosted on Github.
I also have Yubikey NEO and Feitian NFC keys. These can be used with an Android phone to do U2F authentication via NFC. There are currently few applications that use them on a phone.
Here is a nice hands on comparison of many of the U2F keys currently available. https://github.com/hillbrad/U2FReviews
Monday, December 18, 2017
Gherkin Of The Week #10Another plateless Gherkin. This time with POS keycaps. These are keycaps made for cash registers. Each keycap covers more than one switch, there are no stabilizers.
These came from PMK grab bags. They are all DSA profile, I also have some in DCS and SA profile.
PMK sells blanks on their website. Similar relegendable POS keycaps are sold by X-Keys and Genovation.
Wednesday, December 13, 2017
Christmas Tree OrnamentNot a keyboard, but made with many of the same parts. Other than the LEDs and PCB, the rest of the parts I already had.
The PCBs were made a while ago but I only finished assembling it this weekend. The first PCB version had sharp corners and was too dangerous to put on a tree. I rounded the corners and had another set of PCBs made. These are under 100x100mm and can be made at most places at a discount.
I used self flashing LEDs. I ordered some 5mm green/red flashing LEDs on eBay. They were supposed to be diffused (milky white), but they sent clear LEDs. These are way too bright and directional. The replacements they sent were also clear. So I ordered some 5mm RGB diffused flashing LEDs from another seller. The green/red does look more like Christmas tree lights.
There are holes for M2 spacers. Some are too close to the resistors to fit. But there are enough to hold two PCBs together securely. The board is powered from a mini USB connector.
Files on github.
First version on the left, rounded corner version on the right.
The bare PCBs. You can see how sharp the corners were on the original PCB.
I used 1/4 watt resistors on the first one. They fit but the LEDs would not fit in some spots, I had to grind a bit off the edges. The 1/8 watt resistors on the second one don't interfered with the 5mm LEDs.
Tuesday, December 12, 2017
Monday, December 11, 2017
Thursday, December 7, 2017
Black Pro Micro from AliexpressFound these for sale on Aliexpress. Several sellers have them. They are also usually cheaper than the usual blue Pro Micros.
Other than having black soldermask, these are unusual as they use the larger ATmega32u4 package. It's the same chip as on the regular Pro Micro (44QFN), but in a larger form factor (44TQFP). They had to move the other components around to fit the larger chip.
The larger chip could make it easier to solder wires directly to the pins to make use of some of the extra io.
The power circuit seems to be identical to the blue Pro Micro's. It does not suffer from the problem the green Pro Micro does, and works fine in split keyboards.
Top view. The chip barely fits on the board. This one has a green power LED and red TX/RX LEDs.
Bottom view. No components. I have not seen any 3.3v ones for sale. Only 5v, 16Mhz ones.
This is how it was packaged. It came with two 12pin headers.
Side by side with the usual blue Pro Micro clone.
Two installed in a foobar.
Tuesday, December 5, 2017
$5 PCB order from AllPCBAllPCB is currently having a promotion for ten 100mm x 100mm PCBs for $5 shipped.
I ordered some of my 5x5 macropad PCBs. The ordering process is much different than EasyEDA. There is no online preview. It just asks for the size of the board. You have options for different finishes and soldermask colors. There is an actual human that then reviews your design and either accepts it or rejects it. They can either reject it as not producible (errors in design) or add additional charges if you are exceeding the design limits for the base price.
The order arrived via DHL. They are definitely losing money doing these orders.
Monday, December 4, 2017
Gherkin Of The Week #9Another Frankenstein 30% Edward Gherkin. Uses the same aluminum plate as this one. This might actually make a good controller for something.
2U POS keycaps from PMK grab bag. These all have double shot defects.
M2 Spacers and screws.
The aluminum is bare 5052 alloy. Very strong, but scratches easily.
The handles provide some protection for the key caps. Sort of like roll bars.
Keycaps are a mix of DSA and DCS profile.