Machine Shop – Page 219 – The Smell of Molten Projects in the Morning

Kitchen Chair Leg Glide

A stick in the ground marking a repair:

The white plastic glide / slide / foot / cap / whatever is molded around a simple nail that broke a divot out of the foot. Fortunately, I caught it before the nail gouged the kitchen floor.

Under normal conditions, I’d replace the foot from my heap, but, my heap having become somewhat depleted, I swapped in another chair, chipped out the broken plastic, undercut the divot, filled it with JB Kwik epoxy, gooshed the foot in place, and taped it until it cured.

We’ll see how long this lasts …

2016-11-23

Hair Dryer Fuzz

Mary reported that her hair dryer didn’t have nearly as much oomph as in the Good Old Days. After a struggle to remove the rear cover (with no affordance to turn in the direction required to release the hidden latches), this appeared:

One snort from the shop vacuum returned it to the Good Old Days.

That was easy…

2016-11-19

Scale Cover Repair

You can only drop a small kitchen scale so many times before the plastic cover / weighing tray breaks:

Magnum scale cover - glued and clamped — Magnum scale cover – glued and clamped

The trick was to anchor the cover to the glass plate with the big clamp so that the smaller clamps could exert force straight down on the edge, without flipping the lid due to the bevel. With that all set up: apply IPS #4 to the broken edges, insert pieces, apply clamps, wait overnight.

For the record, my morning mug o’ green tea starts with 4 (-0.0 +0.4) g of leaves…

2016-11-17

TCRT5000 Proximity Sensor Mount

Having a few TCRT5000 proximity sensors lying around, I used one for the Color Mixer so folks could just wave a finger to flip the LED colors, rather than pound relentlessly on the top plate:

Color mixer - controls — Color mixer – controls

The stem fits into a slot made with a 3/8 inch end mill:

Prox Sensor Bezel - Slic3r preview — Prox Sensor Bezel – Slic3r preview

You move the cutter by the length of the sensor (10.0 mm will work) to make the slot. In practical terms, drill a hole at the midpoint, insert the cutter, then move ±5.0 mm from the center:

A bead of epoxy around the stem on the bottom of the panel should hold it in place forevermore.

The rectangular inner hole came out a tight push fit for the TCRT5000 sensor, so I didn’t bother gluing it in place and, surprisingly, it survived the day unscathed!

The OpenSCAD source code as a GitHub Gist:

	// TCRT5000 Proximity switch sensor mount
	// Ed Nisley KE4ZNU – October 2016

	Layout = "Build"; // Show Build

	//- Extrusion parameters must match reality!

	ThreadThick = 0.25;
	ThreadWidth = 0.40;

	HoleWindage = 0.2;

	Protrusion = 0.1; // make holes end cleanly

	inch = 25.4;

	function IntegerMultiple(Size,Unit) = Unit * ceil(Size / Unit);

	//———————-
	// Dimensions

	Sensor = [5.9,10.0,7.0];

	SensorHoleCutter = 3/8 * inch;

	echo(str("Cutter dia: ",SensorHoleCutter," mm"));
	echo(str("Cutter motion: ",Sensor[1]," mm"));

	PanelThick = 5.0;

	StemLength = PanelThick + 6*ThreadThick;

	FlangeThick = 3 * ThreadThick;

	//———————-
	// Flange model

	module ProxFlange() {

	difference() {
	union() {
	linear_extrude(height=FlangeThick)
	hull()
	for (i=[-1,1], j=[-1,1])
	translate([iSensor[0],jSensor[1]])
	circle(r=Sensor[0]/2,$fn=8*4);
	translate([0,0,-StemLength])
	linear_extrude(height=StemLength)
	hull()
	for (j=[-1,1])
	translate([0,j*Sensor[1]/2])
	circle(d=SensorHoleCutter,$fn=8*4);
	}
	translate([0,0,-Protrusion])
	cube(Sensor + [HoleWindage,HoleWindage,2*(PanelThick + Protrusion)],center=true);
	}

	}

	//———————-
	// Build it

	if (Layout == "Show")
	ProxFlange();

	if (Layout == "Build")
	translate([0,0,FlangeThick])
	rotate([180,0,0])
	ProxFlange();

view raw Prox Switch Mount.scad hosted with ❤ by GitHub

2016-11-14

Vacuum Tube Lights: Poughkeepsie Day School Mini Maker Faire 2016

Should you be around Poughkeepsie today, drop in on the Poughkeepsie Day School’s Mini Maker Faire, where I’ll be showing off some glowy LED goodness:

21HB5A on platter - orange green — 21HB5A on platter – orange green

The 5U4GB side lighted dual rectifier looks pretty good after I increased the phase between the two LEDs:

5U4GB Full-wave vacuum rectifier - cyan red phase — 5U4GB Full-wave vacuum rectifier – cyan red phase

A gaggle of glowing vacuum tubes makes for a rather static display, though, so I conjured a color mixer so folks could play with the colors:

Color mixer - overview — Color mixer – overview

Three analog potentiometers set the intensity of the pure RGB colors on the 8 mm Genuine Adafruit Neopixels. A closer look at the circuitry shows it’s assembled following a freehand “the bigger the blob, the better the job” soldering technique:

The blended RGB color from a fourth Neopixel backlights the bulb to project a shadow of the filament on the front surface:

Color mixer - bulb detail — Color mixer – bulb detail

It’s worth noting that the three Genuine Adafruit 8 mm Neopixels have a nonstandard RGB color layout, while the knockoff 5050 SMD Neopixel on the bulb has the usual GRB layout. You can’t mix-n-match layouts in a single Neopixel string, so a few lines of hackage rearrange the R and G values to make the mixed colors come out right.

An IR proximity sensor lets you invert the colors with the wave of a fingertip to send Morse code in response to (some of) the vacuum tubes on display nearby. The sensor glows brightly in pure IR, with all the other LEDs going dark:

Color mixer - controls - IR image — Color mixer – controls – IR image

The switch sits in a little printed bezel to make it big enough to see. The slight purple glow in the visible-light picture comes from the camera’s IR sensitivity; you can’t see anything with your (well, my) unaided eyes.

The “chassis” emerged from the wood pile: a slab of laminate flooring and two strips of countertop, with a slab of bronze-tint acrylic from a Genuine IBM PC Printer Stand that had fallen on hard times quite a while ago. Bandsaw to size, belt-sand to smooth; nothing particularly precise, although I did use the Sherline for coordinate drilling:

Color mixer panel - drill setup — Color mixer panel – drill setup

That’s laying it all out by hand to get a feel for what it’ll look like and drilling the holes at actual coordinates to make everything line up neatly.

Hot melt glue and epoxy hold everything together, with foam tape securing the two PCBs. Those cap screws go into 10-32 brass inserts hammered into the laminate flooring strip.

There’s no schematic. Connect the pots to A0 through A2, wire the Neopixels in series from D8 with the bulb LED last in the string, wire the prox sensor to D9, and away you go.

It’s fun to play with colors!

The Arduino source code as a GitHub Gist:

	// Color mixing demo for Mini Maker Faire
	// Ed Nisley – KE4ANU – November 2016

	#include <Adafruit_NeoPixel.h>

	//———-
	// Pin assignments

	#define PIN_NEO 8 // DO – data out to first Neopixel
	#define PIN_HEARTBEAT 13 // DO – Arduino LED

	#define PIN_FLASH 9 // DI – flash button

	#define PIN_POTRED A0 // AI – red potentiometer
	#define PIN_POTGREEN A1 // AI – green potentiometer
	#define PIN_POTBLUE A2 // AI – blue potentiometer

	//———-
	// Constants

	#define PIXELS 4 // number of pixels

	#define PIXEL_RED 2 // physical channel layout
	#define PIXEL_GREEN 1
	#define PIXEL_BLUE 0

	#define PIXEL_MIX (PIXELS – 1) // pixel with mixed color

	#define PIXEL_FLASH (PIXELS – 1) // pixel that flashes

	// update LEDs only this many ms apart (minus loop() overhead)
	#define UPDATEINTERVAL 25ul
	#define UPDATEMS (UPDATEINTERVAL – 1ul)

	//———-
	// Globals

	// instantiate the Neopixel buffer array
	// color order is RGB for 8 mm diffuse LEDs, GRB for mixed 5050 LED at end

	Adafruit_NeoPixel strip = Adafruit_NeoPixel(PIXELS, PIN_NEO, NEO_RGB + NEO_KHZ800);

	uint32_t FullWhite = strip.Color(255,255,255);
	uint32_t FullOff = strip.Color(0,0,0);

	// colors in each LED
	enum pixcolors {RED, GREEN, BLUE, PIXELSIZE};

	uint32_t PotColors[PIXELSIZE];

	uint32_t UniColor;

	unsigned long MillisNow;
	unsigned long MillisThen;

	//– Helper routine for printf()

	int s_putc(char c, FILE *t) {
	Serial.write(c);
	}

	//——————
	// Set the mood

	void setup() {

	pinMode(PIN_HEARTBEAT,OUTPUT);
	digitalWrite(PIN_HEARTBEAT,LOW); // show we arrived

	Serial.begin(57600);
	fdevopen(&s_putc,0); // set up serial output for printf()

	printf("Color Mixer Demo for Mini Maker Faire\r\nEd Nisley – KE4ZNU – November 2016\r\n");

	// set up pixels

	strip.begin();
	strip.show();

	// lamp test: a brilliant white flash on all pixels
	// pixel color layout doesn't matter for a white flash

	printf("Lamp test: flash white\r\n");

	for (byte i=0; i<5 ; i++) {
	for (int j=0; j < strip.numPixels(); j++) { // fill LEDs with white
	strip.setPixelColor(j,FullWhite);
	}
	strip.show();
	delay(500);

	for (int j=0; j < strip.numPixels(); j++) { // fill LEDs with black
	strip.setPixelColor(j,FullOff);
	}
	strip.show();
	delay(500);
	}

	// lamp test: walk a white flash along the string

	printf("Lamp test: walking white\r\n");

	strip.setPixelColor(0,FullWhite);
	strip.show();
	delay(500);

	for (int i=1; i<strip.numPixels(); i++) {
	digitalWrite(PIN_HEARTBEAT,HIGH);
	strip.setPixelColor(i-1,FullOff);
	strip.setPixelColor(i,FullWhite);
	strip.show();
	digitalWrite(PIN_HEARTBEAT,LOW);
	delay(500);
	}

	strip.setPixelColor(strip.numPixels() – 1,FullOff);
	strip.show();
	delay(500);

	MillisNow = MillisThen = millis();

	}

	//——————
	// Run the mood

	void loop() {

	MillisNow = millis();
	if ((MillisNow – MillisThen) >= UPDATEMS) { // time for color change?

	digitalWrite(PIN_HEARTBEAT,HIGH);

	PotColors[RED] = strip.Color(analogRead(PIN_POTRED) >> 2,0,0);
	PotColors[GREEN] = strip.Color(0,analogRead(PIN_POTGREEN) >> 2,0);
	PotColors[BLUE] = strip.Color(0,0,analogRead(PIN_POTBLUE) >> 2);

	strip.setPixelColor(PIXEL_RED,PotColors[RED]); // load up pot indicators
	strip.setPixelColor(PIXEL_GREEN,PotColors[GREEN]);
	strip.setPixelColor(PIXEL_BLUE,PotColors[BLUE]);

	strip.setPixelColor(PIXEL_MIX,strip.getPixelColor(PIXEL_RED) \|
	strip.getPixelColor(PIXEL_GREEN) \|
	strip.getPixelColor(PIXEL_BLUE));
	if (PIXEL_FLASH != PIXEL_MIX) {
	strip.setPixelColor(PIXEL_FLASH,strip.getPixelColor(PIXEL_MIX));
	}

	if (LOW == digitalRead(PIN_FLASH)) { // if flash input active, overlay flash
	strip.setPixelColor(PIXEL_FLASH,0x00FFFFFF ^ strip.getPixelColor(PIXEL_FLASH));
	strip.setPixelColor(PIXEL_RED, 0x00FF0000 ^ strip.getPixelColor(PIXEL_RED));
	strip.setPixelColor(PIXEL_GREEN,0x0000FF00 ^ strip.getPixelColor(PIXEL_GREEN));
	strip.setPixelColor(PIXEL_BLUE, 0x000000FF ^ strip.getPixelColor(PIXEL_BLUE));
	}

	UniColor = 0x000000ff & strip.getPixelColor(PIXELS – 1); // hack to rearrange colors for 5050 LED
	UniColor \|= 0x00ff0000 & (strip.getPixelColor(PIXELS – 1) << 8);
	UniColor \|= 0x0000ff00 & (strip.getPixelColor(PIXELS – 1) >> 8);
	strip.setPixelColor(PIXELS – 1,UniColor);

	strip.show(); // send out colors

	MillisThen = MillisNow;
	digitalWrite(PIN_HEARTBEAT,LOW);
	}

	}

view raw ColorMixer.ino hosted with ❤ by GitHub

2016-11-12

Vacuum Tube LEDs: Mogul Socket With Platters

Adding two hard drive platters draws attention away from the printed puck holding the microcontroller:

500 W Incandescent - Mogul socket with platters — 500 W Incandescent – Mogul socket with platters

Granted, it looks odd. I think it’s a step in the right direction, if there is any right direction at all.

2016-11-11

More Kickstand Plates

Having recently left the last of the kickstand plates somewhere along our route, I bandsawed, belt-sanded, and Forstner-drilled a new set:

The slightly rectangular shape extracted four plates from of a scrap of 3/8 inch plywood, with almost nothing left over. The fourth plate had already found its way into the under-seat bag by the time I thought of a picture.

My can of fluorescent red paint having lost its mojo since the most recent application, these shall remain unpainted forever more; as even forget-me-not red seems to have little effect, that may not matter.

2016-11-08