Second Badge Prototype, LayerOne is closing in fast

A project log for LayerOne 2015 Badge

This years LayerOne conference badge.

charliexcharliex 04/12/2015 at 17:090 Comments

The VoCore based badge PCB's arrived, and i built one yesterday.

worked except for the usb which was mirrored! i looked at the symbol in eagle and it was a box with USB written so edited that part with vcc/d-/d+/gnd so it'd be spotted (con-amp.lbr) booted up fine after that. If usb is backwards you'll see >3V on the d+/d- lines which at first we thought short or bad connector etc etc. Luckily its a thru hole part so we just installed it on the other side of the board and all good.

I cut down a 10mmx10mm8mm heatsink on the bandsaw and that seemed to work fine too.

Updated to the latest OpenWRT build and flashed it with sysupgrade.

sysupgrade -v /tmp/openwrt-ramips-rt305x-vocore-squashfs-sysupgrade.bin

luci didn't install for some reason i haven't looked into yet, even though i have it in the feed so

opkg update
opkg install luci

after ssh/telneting into the vocore.

So far so good. Should be an interesting build for people, and for us an easy build so we can actually go to the conference this year. Wifi + Two ethernet ports ( default same port)

The other badge we've decided to drop the M74VHC1GT125DF2G in favour of a different 3v>5v converter, kris built three boards and one worked, the other two the fault lay in that chip, it is tiny and its a challenge to hand solder. I will make the pads a tad bigger for handwork but kris is an expert in soldering and if she had issues, the attendees definitely will.

Haven't decided what to use instead yet, and i'll do it in parallel to the 125 since last minute board changes are never fun.

The PSOC4 is amazing, when i was programming the chips with the 3.3v programmer the leds all started working (even blue) which is crazy, they were about 2.85V!. The PSOC4 can go to down to about 1.5V before it gives up. for a 5.5V top limit, it's hard to beat.

Also we tested not having cap's per LED since its 22 extra caps to solder in, everything we've ever seen has that cap but it worked fine and checking with the scope the power and signal were just fine. the 5V to 3.3V VREG just needed a 450nF cap to smooth out the signal to the LEDs.

We also did a test of the daisy chaining of the boards, and that worked. We've built a number of LED boards with daisy chain capabilities but none of them we've actually tried it on.

Just need to add sponsor artwork (thanks HAD!) and get the boards in for final manufacturing

We're also doing a hebocon at L1 next month.

Ordered an additional 200 CR123A batteries, 300 battery holders, microsd card holders, mini usb connectors and heatsinks. Just need to track down another logic level converter that is fast enough, not too big, won't break the budge and is easier to solder.

I'm using the same jumper + two pins for the on/off switch again, and there is a diode to protect against improper battery insertion CR123A's are no joke.

The ESP8266 works, and they can talk to each other and the other badge, not sure where we'll go with that. I'm usually so busy getting the hardware ready i don't get time to code up awesome stuff for people to hack on. But I put all the basics in there, light patterns and code to talk to the wifi , the other is busybox+openwrt.

This badge has more processing power than last years , but only in some ways. Since the last had cpu+fpga+asic. Much much less parts this time ( since we're using a prebuilt cpu module )

The Ws2812b's have some interesting failures, usually an internal wire just comes loose and you can often put a little pressure in the front and it'll pop on but can only maybe be fixed by being super lucky and heating it, more likely it'll kill it so dump it. The other one is the data line gets shorted or something and it upsets the whole chain, so you get random colours on the other LEDs.