The dark season means project time again

Blog ยป The dark season means project time again

Posted on 1322354936|%A: %d %B, %Y|agohover

magic_eye.jpg

Most years I don't like to have too many indoor projects while the weather is good, thought last year I made an exception. In Seattle, prime project season is roughly November-April, and this year I'm kicking it off by finishing some of last year's unfinished (or underdeveloped) projects.

Right now, I'm finishing the magic eye stereo VU meter. Last year I left it just barely complete enough to demonstrate that the tubes work. That meant I got a half-baked power supply working (and then only badly), and I used an external amplifier to drive the audio inputs. This year, I reworked the power supply and I'm adding an internal amplifier so the unit is self-contained and driven by a line level signal. I'm very pleased with how it's turning out, and I think it's going to look stupendously awesome when it's done.

Earlier this month, I reworked the firmware the RF scanner. After living with it for a year or so, the slowness of the refresh rate bothered me and I thought I could do better. This turned out to be an exercise in chasing bottlenecks until I found an external limiting factor. It's not always obvious what the limiting factor will be. In this case it turned out to be close contest between the SPI speed of the radio module interface and the time delay needed for the radio to stabilize before sampling channel strength.

The result is quite satisfying. Refresh rate is now nearly 3x the speed of the old build:

I also plan to finish my IV-4 / IV-17 VFD tube clock, and I have a couple of other project ideas that might be promising. I might even do a straight-up software project for the first time in a while, to celebrate my new Android tablet.

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