Obviously, you’ll pick a different keymap name than I did. All the files mentioned below will reside in the new subdirectory, which starts out with only a keymap.c file copied from the default layout.
If you had different hardware, you could specify the driver with a WS2812_DRIVER option.
QMK can also control single-color LEDs with PWM (a.k.a. backlighting), and per-key RGB LEDs (a.k.a. RGB Matrix). These functions, their configuration / controls / data, and their documentation overlap and intermingle to the extent that I spent most of my time figuring out what not to include.
The first two lines describe a single WS2812 RGB LED wired to pin B2 (a.k.a. MOSI) of the Atmel 32U4 microcontroller. The default Reset duration and Byte Order values work for the LED I used
Protip: swapping the order from GRB to RGB is a quick way to discover if the firmware actually writes to the LED, even before you get anything else working: it’ll be red with the proper setting and green with the wrong one.
Dialing the maximum intensity down works well with a bright LED shining directly at your face from a foot away.
Turning on RGBLIGHT_LAYERS is what makes this whole thing happen. The RGBLIGHT_EFFECT_RGB_TEST option enables a simple test animation at the cost of a few hundred bytes of code space; remove that line after everything works.
The last two lines remove the debugging facilities; as always with microcontroller projects, there’s enough room for either your code or the debugger required to get it running, but not both.
With those files set up, the keymap.c file does the heavy lifting:
Undefine LED_LL to enable the test mode, compile, flash, and the LED should cycle red / green / blue forever; you also need the RGB_TEST option in the config.h file.
Define LED_LL and layer lighting should then Just Work™, with the LED glowing:
White for the basic layer with all the letters
Magenta with the Fun key pressed
Cyan with the Esc key pressed
The key map code defines colors for layers that don’t yet exist, but it should get you started.
For convenience, I wadded all three QMK files into a GitHub Gist.
The LED is kinda subtle:
Atreus keyboard – LED installed
As you might expect, figuring all that out took much longer than for you to read about it, but now I have a chance of remembering what I did.
After replacing the nozzle and the filament drive body on the M2, I figured I might as well throw all the balls in the air and switch to PrusaSlicer for all my slicing needs. It’s built from the Slic3r project, gaining features used by Prusa’s printers / filaments and a considerably improved UI, with a full-time paid staff working on it:
You have been warned: consider this as a serving suggestion, not a finished product.
Because everything I design looks more-or-less like a bracket, I absolutely don’t care about surface finish, and I’m content to use only a few colors of PETG from a single supplier, a single Slic3r configuration has sufficed for nearly everything I print. A few manual tweaks for specific models, perhaps to change the number of perimeters or the infill percentage, handle the remaining cases.
With all that in mind, here’s the current result of File → Export → Export Config as a GitHub Gist:
# generated by PrusaSlicer 2.2.0+linux-x64 on 2021-01-01 at 13:33:03 UTC
avoid_crossing_perimeters = 0
bed_custom_model =
bed_custom_texture =
bed_shape = -100x-125,100x-125,100x125,-100x125
bed_temperature = 90
before_layer_gcode =
between_objects_gcode =
bottom_fill_pattern = hilbertcurve
bottom_solid_layers = 3
bottom_solid_min_thickness = 0
bridge_acceleration = 0
bridge_angle = 0
bridge_fan_speed = 100
bridge_flow_ratio = 1
bridge_speed = 50
brim_width = 0
clip_multipart_objects = 1
colorprint_heights =
complete_objects = 0
cooling = 1
cooling_tube_length = 5
cooling_tube_retraction = 91.5
default_acceleration = 0
default_filament_profile = ""
default_print_profile =
deretract_speed = 0
disable_fan_first_layers = 6
dont_support_bridges = 1
draft_shield = 0
duplicate_distance = 6
elefant_foot_compensation = 0
end_filament_gcode = "; Filament-specific end gcode \n;END gcode for filament\n"
end_gcode = ;-- PrusaSlicer End G-Code for M2 starts --\n; Ed Nisley KE4NZU - 15 November 2013\nG1 Z160 F2000 ; lower bed\nG1 X135 Y100 F30000 ; nozzle to right, bed front\nM104 S0 ; drop extruder temperature\nM140 S0 ; drop bed temperature\nM106 S0 ; bed fan off\nM84 ; disable motors\n;-- PrusaSlicer End G-Code ends --\n\n
start_gcode = ;-- PrusaSlicer Start G-Code for M2 starts --\n; Ed Nisley KE4NZU\n; Makergear V4 hot end\n; Origin at platform center, set by MANUAL_X_HOME_POS compiled constants\n; Z-min switch at platform, must move nozzle to X=135 to clear\nG90 ; absolute coordinates\nG21 ; millimeters\nM83 ; relative extrusion distance\nM104 S[first_layer_temperature] ; start extruder heating\nM140 S[first_layer_bed_temperature] ; start bed heating\nM17 ; enable steppers\nG4 P500 ; ... wait for power up\nG92 Z0 ; set Z to zero, wherever it might be now\nG0 Z10 F1000 ; move platform downward to clear nozzle; may crash at bottom\nG28 Y ; home Y to clear plate, offset from compiled constant\nG28 X ; home X, offset from M206 X, offset from compiled constant\nG0 X135 Y0 F15000 ; move off platform to right side, center Y\nG28 Z ; home Z to platform switch, offset from M206 Z measured\nG0 Z2.0 F1000 ; get air under switch\nG0 Y-126 F10000 ; set up for priming, zig around corner\nG0 X0 ; center X\nG0 Y-124.5 ; just over platform edge\nG0 Z0 F500 ; exactly at platform\nM190 S[first_layer_bed_temperature] ; wait for bed to finish heating\nM109 S[first_layer_temperature] ; set extruder temperature and wait\nG1 E20 F300 ; prime to get pressure, generate blob on edge\nG0 Y-123 F5000 ; shear off blob\nG0 X15 F15000 ; jerk away from blob, move over surface\nG4 P500 ; pause to attach\nG1 X45 F500 ; slowly smear snot to clear nozzle\nG1 Z1.0 F2000 ; clear bed for travel\n;-- PrusaSlicer Start G-Code ends --\n
Having a customizable keyboard like the KeyboardIO Atreus means one must customize it. As it turns out, I wanted to use some features of the underlying QMKKaleidoscope firmware that aren’t exposed by Chrysalis, KeyboardIO’s otherwise competent keymap configuration utility, so what you see below runs on hard mode.
Start by installing QMK, compiling the default Atreus layout, and flashing the keyboard just to confirm all the steps work:
Atreus keyboard – overview
With all that working, add (or create) two lines to the rules.mk file in the keymap directory you’re tweaking:
Enabling Auto-Shift lets you generate shifted characters (like Z) by briefly holding down the unshifted key (like z). This requires unlearning an entire lifetime of touch typing practice, but is definitely worthwhile; if a thumb still reaches for the shift key, there’s no harm done. There are, of course, a myriad options, all of which I left unchanged.
Complex passwords suffer, as you must blind-type carefully while tapping each key rapidly.
Enabling Tap Dance lets a key generate one character when tapped and another when double-tapped; you can go crazy with more taps. An enum{} in the keymap.c file generates indexes for the keys and an array holds the action definitions:
The throttle knob on our MTD snowthrower (a.k.a. snowblower) cracked apart around its metal shaft when I pulled it upward. A temporary fix involving duct tape and cable ties sufficed to start the engine, although the usual intense vibration shook the knob loosesomewhere along the driveway during the next hour.
Although I have no photographic evidence, I did make a few quick measurements:
Throttle Knob Dimension Doodles
It fits an MTD model E6A4E, but I suspect nearly all their engines have identical throttle shafts:
Snowthrower Throttle Knob – stem end – solid model
The only practical way to build the thing has it standing on the shaft end, surrounded by a brim to improve adhesion, so I added (actually, subtracted) a pair of holes for music-wire reinforcements:
Snowthrower throttle knob – reinforcing wires
It definitely has a stylin’ look, next to the original choke control knob:
Snowthrower throttle knob – installed
I omitted the finger grip grooves for obvious reasons.
The slot-and-hole came out slightly smaller than the metal shaft and, rather than wait for epoxy to cure, I deployed a 230 W soldering gun (not a piddly temperature-controlled iron suitable for electronics) on the shaft and melted it into the knob.
More snow may arrive this week and I printed another knob just in case …
Adding a bit of trim to the bottom of the LED spider makes it look better and helps keep the strut wires in place:
Astable Multivibrator – Alkaline – Radome trim
It’s obviously impossible to build like that, so it’s split across the middle of the strut:
Astable Multivibrator – Alkaline – Radome trim
Glue it together with black adhesive and a couple of clamps:
LED Spider – glue clamping
The aluminum fixtures (jigs?) are epoxied around snippets of strut wire aligning the spider parts:
LED Spider – gluing fixture
Those grossly oversized holes came pre-drilled in an otherwise suitable aluminum rod from the Little Tray o’ Cutoffs. I faced off the ends, chopped the rod in two, recessed the new ends, and declared victory. Might need better ones at some point, but they’ll do for now.
Next step: wire up an astable with a yellow LED to go with the green and blueboosted LEDs.
After about a year of streaming music, the music died over the course of a month, producing progressively bizarre symptoms on all the local Icecast stations. Killing the streaming server and yanking all the USB memory sticks produced this tableau:
USB Memory – streamer failures
The USB 2.0 32 GB SanDisk Cruzer Fit (tiny, black, upper left) holds images from various network cameras and is not involved with music. It’s nigh onto seven years old and, apparently, still going strong.
The USB 2.0 Centron (gray-and-retroreflective, upper right) was forgotten from the last time I set up a drive for our Forester’s player. There’s another one just like it in the car; they’re impossibly old, as you’d expect from their minuscule size.
The USB 3.0 64 GB Samsung Fit (small, white, lower left) is totally dead, to the extent it doesn’t even announce its presence when plugged into a USB socket. It’s 2.5 years into a five year warranty, but their new USB 3.1 version is twelve bucks; Samsung wins. It formerly contained an extensive selection of public-domain music.
The 64 GB Sandisk Cruzer (huge, black, lower right) suffered some serious damage:
sudo mount -o ro /dev/sdg1 /mnt/part
ll /mnt/part
ls: cannot access '/mnt/part/PILZ': Input/output error
total 384K
drwxr-xr-x 6 ed users 4.0K Nov 28 2019 ./
drwxr-xr-x 17 root root 4.0K Jun 7 2019 ../
-rw-r--r-- 1 ed ed 215K Mar 9 2019 CDClassical.m3u
drwxrwxr-x 56 ed ed 4.0K Mar 9 2019 Classical/
drwx------ 2 root root 16K Mar 9 2019 lost+found/
d????????? ? ? ? ? ? PILZ/
drwxrwxr-x 116 ed ed 12K Mar 9 2019 Pop/
-rw-r--r-- 1 ed ed 117K Nov 28 2019 Pop.m3u
It still contains a fair amount of music ripped from the CDs we’ve collected over the decades, but it’s obviously unusable. Just for fun, I tried reformatting and copying some files to it, but it eventually hard-crashed with I/O errors:
[37787.872410] usb 2-1: new high-speed USB device number 2 using xhci_hcd
[37788.013027] usb 2-1: New USB device found, idVendor=0781, idProduct=5530, bcdDevice= 1.00
[37788.013030] usb 2-1: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[37788.013032] usb 2-1: Product: Cruzer
[37788.013034] usb 2-1: Manufacturer: SanDisk
[37788.013036] usb 2-1: SerialNumber: 4C530001151215101233
[37788.013604] usb-storage 2-1:1.0: USB Mass Storage device detected
[37788.014778] scsi host9: usb-storage 2-1:1.0
[37789.033409] scsi 9:0:0:0: Direct-Access SanDisk Cruzer 1.00 PQ: 0 ANSI: 6
[37789.034569] sd 9:0:0:0: [sdf] 120225792 512-byte logical blocks: (61.6 GB/57.3 GiB)
[37789.035820] sd 9:0:0:0: [sdf] Write Protect is off
[37789.035825] sd 9:0:0:0: [sdf] Mode Sense: 43 00 00 00
[37789.036137] sd 9:0:0:0: [sdf] Write cache: disabled, read cache: enabled, doesn't support DPO or FUA
[37789.086533] sdf: sdf1
[37789.089418] sd 9:0:0:0: [sdf] Attached SCSI removable disk
[38035.071013] EXT4-fs (sdf1): mounting ext3 file system using the ext4 subsystem
[38035.183172] EXT4-fs (sdf1): mounted filesystem with ordered data mode. Opts: (null)
[38485.302549] usb 2-1: reset high-speed USB device number 2 using xhci_hcd
[38490.622285] usb 2-1: device descriptor read/64, error -110
[38506.195617] usb 2-1: device descriptor read/64, error -110
[38506.425616] usb 2-1: reset high-speed USB device number 2 using xhci_hcd
[38511.742339] usb 2-1: device descriptor read/64, error -110
<<< snippage >>>
[38548.845743] usb 2-1: USB disconnect, device number 2
[38548.858925] blk_update_request: I/O error, dev sdf, sector 99556320 op 0x1:(WRITE) flags 0x4800 phys_seg 30 prio class 0
[38548.858933] EXT4-fs warning (device sdf1): ext4_end_bio:309: I/O error 10 writing to inode 1531939 (offset 0 size 0 starting block 12444541
)
[38548.858937] Buffer I/O error on device sdf1, logical block 12444284
[38548.858944] EXT4-fs warning (device sdf1): ext4_end_bio:309: I/O error 10 writing to inode 1531939 (offset 0 size 0 starting block 12444542
)
<<< snippage >>>
[38548.858984] Buffer I/O error on device sdf1, logical block 12444293
[38548.859034] blk_update_request: I/O error, dev sdf, sector 99017520 op 0x1:(WRITE) flags 0x4000 phys_seg 3 prio class 0
[38548.859158] blk_update_request: I/O error, dev sdf, sector 99556560 op 0x1:(WRITE) flags 0x4800 phys_seg 30 prio class 0
[38548.859224] blk_update_request: I/O error, dev sdf, sector 99017760 op 0x1:(WRITE) flags 0x4000 phys_seg 2 prio class 0
[38548.859237] blk_update_request: I/O error, dev sdf, sector 99018000 op 0x1:(WRITE) flags 0x4000 phys_seg 2 prio class 0
>>
[38549.230765] JBD2: Detected IO errors while flushing file data on sdf1-8
[38549.230920] Aborting journal on device sdf1-8.
[38549.231008] Buffer I/O error on dev sdf1, logical block 1545, lost sync page write
[38549.231011] JBD2: Error -5 detected when updating journal superblock for sdf1-8.
[38549.231325] Buffer I/O error on dev sdf1, logical block 0, lost sync page write
[38549.231332] EXT4-fs (sdf1): I/O error while writing superblock
[38549.231333] EXT4-fs error (device sdf1): ext4_journal_check_start:61: Detected aborted journal
[38549.231334] EXT4-fs (sdf1): Remounting filesystem read-only
<<< and so forth and so on >>>
The Icecast streaming server reads data continuously from the USB sticks and, given that I set up half a dozen “stations”, there’s plenty of reading going on. The drives are formatted as ext3 and mounted with the noatime option, so there shouldn’t be any writing going on, but it seems a year of constant reading can kill a USB drive.
Fortunately, the original data lives elsewhere, with scripts to copy the appropriate files to the right places, so rebuilding the drives on a pair of new USB sticks wasn’t a big deal.