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New 25Mar2025. Updated 29Apr2025. This note is in group Technology (plus My XMOS pages). Previous fringe was IEEE-COPA 2021 fringe.

COPA conference

2025 Concurrent Processes Architectures (COPA) and Embedded Systems, see IEEE COPA 2025 – PROGRAMME. It is under the IEEE umbrella.

Comment after the conference. Number of persons on site plus some of us via Teams/Zoom were less than 10 persons. So I guess it was more like a «meeting» than a «conference» as such, if size matters.

Can gears that engage only so good make the machine run?

Abstract: This conference «fringe» presentation explains an implementation which reads from a MEMS microphone and writes to a headset DAC. To avoid using an external PLL chip, clock output pulses rather unusually vary some in time. The timing of these «staccato» pulses is taken from a software table with 10 ns tick resolution (100 MHz). The pattern thus generated repeats exactly every 62.5 µs, giving a stereo frame rate of 16,000 Hz. The table contains 128 elements; two edges per pulse * 32 bits * two channels, each representing the number of ticks to the next clock signal edge output. The presentation shows that this controlled unevenness correctly picks up the data bits from the microphone chip or delivers the data bits to the headset chip. A processor from XMOS (UK) is used for this.

Read at

• Keynote – Source: Apple Keynote (13.1) (29.7 MB)
• PDF – Export with one build per page (29.4 MB)
• PowerPoint – Export (37.6 MB). (Disclaimer: I have not run this pptx since I don’t have PowerPoint)

Errata

1. I presented the lecture on 21Apr2025 and I think I said that the FFT on the XMOS X2 processor took «about 450 ns«. The correct is of course is «about 450 µs«
2. …

EasyChair

This conference uses EasyChair for publishing (here). Also for fringe presentations. History:

1. 25Mar2025 ver1 uploaded
2. 27Mar2025 ver2 uploaded

Acknowledgement

Thanks to Henrik Austad for valuable feedback on ver1.

The physical gear on the photo

This chapter is off topic, as the photo is only meant for associations. But I thought it might be nice to know about the motive. Plus, this crane is not much covered on the web.

* From a photo montage I made (here) :
«The «boiler» derrick type crane («kjelkran») at Solsiden shopping mall. Remains of original from the 1840s at Trondhjems Mekaniske Værksted (TMV). Moved from location at «up» to «down» the river around 1888 (or 1892?), then to this position for display around 2003. Photos 2018-2025 by Øyvind Teig.»
This source seems to quote 1888 at p.19 and 1892 at p.267:  «Trondhjems mek. verksted a.s. 1843-1983» by Finn R. Hansen (1995). If you are in Norway you may read it at the National Library here. See pages 19 & 267 (descriptions) and 268 (photo). No ISBN, but BIBSYS num 999514769474702202. This source also mentions that it was first moved from the original location in 1872 (p.267). In other words, this should be its fourth location!
* I assume that the hook could be moved so much «in» that it could hang above and inside the pier edge, so that objects could be lifted from the pier to the ship(?) I am not certain whether the present mounting would suffice in this respect, though.
* There are two cranes by the Solsiden shopping center («kjøpesenter») these days. You can see both here.
* From my Italian engineer email pal Pietro, after I had sent him the url to this site: «Can gears that engage only so good make the machine run? Yes: the machine works … and well. In the pic there are the gears that make the crane arm tip ‘out’ or ‘in’ although the engine always turns in one direction only. All this is possible from the central lever that by engaging the left bevel gear makes the crane tip ‘in’ while when it engages the right bevel gear it makes the arm tip ‘out’. About 50 years ago I had this type of gear on the construction site, except it made the crane rotate in either direction …… 50 years ago, sic!«.
* Leonardo da Vinci (1452 – 1519) invented much more complicated gears than this. For one particular example, see Reproduction of page from notebook of Leonardo da Vinci showing a geared device assembled and disassembled LCCN2006681098 at Wikimedia Commons. There also is a video at YouTube, see L’innovazione di Leonardo nel disegno di macchine. L’argano per sollevare pesi by Museo Scienza e Tecnologia Leonardo da Vinci