From a6e14085046c7cf24f8ed27673a9c365d1565bf1 Mon Sep 17 00:00:00 2001
From: jaseg <git@jaseg.de>
Date: Tue, 13 Jul 2021 15:58:30 +0200
Subject: Give source on motor power estimate
compare to large sunon fan
---
paper/Makefile | 12 +++++++-----
paper/ihsm_paper.tex | 10 +++++++---
2 files changed, 14 insertions(+), 8 deletions(-)
diff --git a/paper/Makefile b/paper/Makefile
index 051e628..e230536 100644
--- a/paper/Makefile
+++ b/paper/Makefile
@@ -15,16 +15,18 @@ brief_tex ?= ihsm_tech_report
sub_stem ?= cant-touch-this-ihsm-paper
VERSION_STRING := $(shell git describe --tags --long --dirty)
+SHORT_VERSION_STRING := $(shell git describe --tags)
all: ${main_tex}.pdf ${brief_tex}.pdf
.PHONY: submission-outputs
submission: diff cover-letter ${main_tex}.pdf
- cp ${main_tex}.pdf ${sub_stem}-${VERSION_STRING}.pdf
- cp ${main_tex}_diff.pdf ${sub_stem}-${VERSION_STRING}-diff.pdf
- cp tches-22-01-changes.pdf ${sub_stem}-${VERSION_STRING}-cover-letter.pdf
- rm -f ${sub_stem}-${VERSION_STRING}-supplementary.zip
- zip -r ${sub_stem}-${VERSION_STRING}-supplementary.zip ${sub_stem}-${VERSION_STRING}-diff.pdf ${sub_stem}-${VERSION_STRING}-cover-letter.pdf
+ cp ${main_tex}.pdf ${sub_stem}-${SHORT_VERSION_STRING}-revised.pdf
+ cp ${main_tex}_diff.pdf ${sub_stem}-${SHORT_VERSION_STRING}-diff.pdf
+ cp cant-touch-this-ihsm-paper-v2.0.pdf cant-touch-this-ihsm-paper-v2.0-original.pdf
+ cp tches-22-01-changes.pdf ${sub_stem}-${SHORT_VERSION_STRING}-cover-letter.pdf
+ rm -f ${sub_stem}-${SHORT_VERSION_STRING}-supplementary.zip
+ zip -r ${sub_stem}-${SHORT_VERSION_STRING}-supplementary.zip ${sub_stem}-${SHORT_VERSION_STRING}-diff.pdf ${sub_stem}-${SHORT_VERSION_STRING}-cover-letter.pdf ${sub_stem}-${SHORT_VERSION_STRING}-revised.pdf cant-touch-this-ihsm-paper-v2.0-original.pdf
.PHONY: cover-letter
cover-letter: tches-22-01-changes.pdf
diff --git a/paper/ihsm_paper.tex b/paper/ihsm_paper.tex
index 851da46..f4cea28 100644
--- a/paper/ihsm_paper.tex
+++ b/paper/ihsm_paper.tex
@@ -420,9 +420,13 @@ motor requires more power than the mesh monitoring circuit of a traditional HSM.
Uninterruptible Power Supply (UPS) can be used, but in practice a productized IHSM might have a smaller backup battery
integrated into its case. Conservatively assuming an average operating power consumption of $\SI{10}{\watt}$ for an
IHSM's motor, a single large laptop battery with a capacity of $\SI{100}{\watt\hour}$~\cite{faa2018} could already power
-an IHSM for 10 hours continuously. If a built-in battery is undesirable, or if power outages of more than a few seconds
-at a time are unlikely (e.g.\ because the IHSM is connected to an external UPS or generator), the IHSM's rotor itself
-can be used as a flywheel for energy storage.
+an IHSM for 10 hours continuously. $\SI{10}{\watt}$ is a reasonable high estimate given that there are large industrial
+fans rated at lower wattages. For example, \texttt{CF2207LBL-000U-HB9}, a $\SI{250}{\milli\meter}$ diameter
+$\SI{7.8}{\meter^3\per\minute}$ industrial axial fan made by Sunon is rated at only
+$\SI{6.6}{\watt}$\footnote{\url{https://www.digikey.com/en/products/detail/sunon-fans/CF2207LBL-000U-HB9/9083282}}. If
+a built-in battery is undesirable, or if power outages of more than a few seconds at a time are unlikely (e.g.\ because
+the IHSM is connected to an external UPS or generator), the IHSM's rotor itself can be used as a flywheel for energy
+storage.
\paragraph{Spurious alarms.}
Even with all components working to their specification, an IHSM could still catastrophically fail if for some reason
--
cgit