The Smell of Molten Projects in the Morning
Ed Nisley's Blog: Shop notes, electronics, firmware, machinery, 3D printing, laser cuttery, and curiosities. Contents: 100% human thinking, 0% AI slop.
An approaching cyclist warned to watch out for the snapping turtle:
This one claims the pond near Page Industrial Park along the Dutchess Rail Trail:
We’ll not dispute any snapper’s territory!
I’m hauling PYO apples from Prospect Hill Orchards in the hills on the west side of the Hudson; it was a lovely fall day for a 25 mile ride!
The Sony HDR-AX30V helmet camera puts far more demands on its battery than the Planet Bike Superflash:
The four traces on the right show the BatMax NP-BX1 lithium batteries (cells, really) originally stored about 3 W·h when they arrived in March 2020. The four solid traces to their left show the capacity dropped to a little over 2 W·h after two riding seasons. Batteries B and C started out above average and are now below, for whatever that means.
The red dotted trace shows the effect of not using the NP-BX1 test holder for that length of time; those homebrew contact pins apparently needed some exercise.
Having replaced the Planet Bike Superflash on Mary’s Tour Easy with a 1 W red LED, testing the eight Panasonic Eneloop AAA cells that have been powering it (and the one on my bike) for the last four years seemed useful:
The sheaf of curves over on the right came from the first full charge, with the untidy collection below them show the current state after a full charge. This is at an unreasonably high 500 mA discharge.
The overall capacity has dropped by 10%, which isn’t all that bad, but the 10% voltage reduction toward the end of the curves is a Bad Thing for an LED flasher intended to run from 1.5 V alkaline cells. In practice, I recharge the batteries once a week while they are still going strong, but the difference between alkalines and NiMH cells is obvious even at full charge.
Now I can run four pairs through the aging Superflash on my bike …
The Bondhus Lifetime Guarantee works, as a replacement wrench just arrived:
A close look at the aligned tips suggests the defective wrench blank was mis-chucked in the machine cutting the ball end:
All’s well that ends well: thank you, Bondhus!
There being nothing like a good new problem to take one’s mind off all one’s old problems:
It’s basically the same as the lower blade guide, except coming from a stick of 5/8 inch acetal. A scant 6 mm stem goes into the vertical square rod, with a flat matching the setscrew coming up from the bottom to hold it in proper alignment.
I came within a heartbeat of cutting the slot parallel to the flat.
It worked OK while cutting a chunk of stout aluminum tube: so far, so good!
The impressive chunk of hardware is the OEM blade guide, with the brass tube for coolant flow all over the bearings. It’s mostly intended for use with the diamond blade, so I’ll swap it back in when I finally get around to cutting some slate for base plates.
There’s just enough slack in the LED wiring to clip a Tek current probe in there:
Which reveals the LED current waveform:
The LED is on continuously, except for the two 75 ms Morse code dits in the upper trace.
The lower trace shows the current ramping up at the end of the first dit, from zero to 400 mA in 1.5 ms.
Clamping the probe around the 6.3 V power supply lead:
The supply current includes maybe 20 mA for the Arduino running the Morse code program and the current ramps up from there to about 250 mA when the LED is on.
The LED drops 2.6 V at 400 mA, so it dissipates a smidge over 1 W. The 2.0 Ω current sense resistor (3.3 Ω in parallel with 5.1 Ω) dissipates 800 mV × 400 mA = 320 mW.
The dissipation from the Bafang headlight output, including the Arduino, is 1.6 W.
The running light ticks along at the hot side of comfortably warm on the Electronics Workbench and runs barely warm in free air out on the bike, so I’ll define it to be Good Enough™.
The rear running light definitely has an industrial look:
The front of the light has plenty of clearance from the seat mesh:
Out on the road, the 1 W LED appears about as bright as automotive running lights:
The blink pattern makes it perfectly visible in sunlight, although I’d prefer somewhat larger optics:
In shaded conditions, it’s downright conspicuous:
At any reasonable distance, the 10° beam covers much of the road behind the bike:
You may not know what the occulting red light represents, but something ahead is worthy of your attention.
The Arduino source code producing the two dits:
// Tour Easy Running Light
// Ed Nisley - KE4ZNU
// September 2021
#include <morse.h>
#define PIN_OUTPUT 13
// second param: true = active low output
LEDMorseSender Morser(PIN_OUTPUT,true,(float)10.0);
void setup()
{
Morser.setup();
Morser.setMessage(String("qst de ke4znu "));
Morser.sendBlocking();
// Morser.setWPM((float)3.0);
Morser.setSpeed(75);
Morser.setMessage(String("i "));
}
void loop()
{
if (!Morser.continueSending())
Morser.startSending();
}
Looks good to me, anyhow.
The Smell of Molten Projects in the Morning 