Andrew Cooke | Contents | Latest | RSS | Previous | Next


Welcome to my blog, which was once a mailing list of the same name and is still generated by mail. Please reply via the "comment" links.

Always interested in offers/projects/new ideas. Eclectic experience in fields like: numerical computing; Python web; Java enterprise; functional languages; GPGPU; SQL databases; etc. Based in Santiago, Chile; telecommute worldwide. CV; email.

Personal Projects

Choochoo Training Diary

Last 100 entries

Surprise Paradox; [Books] Good Author List; [Computing] Efficient queries with grouping in Postgres; [Computing] Automatic Wake (Linux); [Computing] AWS CDK Aspects in Go; [Bike] Adidas Gravel Shoes; [Computing, Horror] Biological Chips; [Books] Weird Lit Recs; [Covid] Extended SIR Models; [Art] York-based Printmaker; [Physics] Quantum Transitions are not Instantaneous; [Computing] AI and Drum Machines; [Computing] Probabilities, Stopping Times, Martingales; bpftrace Intro Article; [Computing] Starlab Systems - Linux Laptops; [Computing] Extended Berkeley Packet Filter; [Green] Mainspring Linear Generator; Better Approach; Rummikub Solver; Chilean Poetry; Felicitations - Empowerment Grant; [Bike] Fixing Spyre Brakes (That Need Constant Adjustment); [Computing, Music] Raspberry Pi Media (Audio) Streamer; [Computing] Amazing Hack To Embed DSL In Python; [Bike] Ruta Del Condor (El Alfalfal); [Bike] Estimating Power On Climbs; [Computing] Applying Azure B2C Authentication To Function Apps; [Bike] Gearing On The Back Of An Envelope; [Computing] Okular and Postscript in OpenSuse; There's a fix!; [Computing] Fail2Ban on OpenSuse Leap 15.3 (NFTables); [Cycling, Computing] Power Calculation and Brakes; [Hardware, Computing] Amazing Pockit Computer; Bullying; How I Am - 3 Years Post Accident, 8+ Years With MS; [USA Politics] In America's Uncivil War Republicans Are The Aggressors; [Programming] Selenium and Python; Better Walking Data; [Bike] How Fast Before Walking More Efficient Than Cycling?; [COVID] Coronavirus And Cycling; [Programming] Docker on OpenSuse; Cadence v Speed; [Bike] Gearing For Real Cyclists; [Programming] React plotting - visx; [Programming] React Leaflet; AliExpress Independent Sellers; Applebaum - Twilight of Democracy; [Politics] Back + US Elections; [Programming,Exercise] Simple Timer Script; [News] 2019: The year revolt went global; [Politics] The world's most-surveilled cities; [Bike] Hope Freehub; [Restaurant] Mama Chau's (Chinese, Providencia); [Politics] Brexit Podcast; [Diary] Pneumonia; [Politics] Britain's Reichstag Fire moment; install cairo; [Programming] GCC Sanitizer Flags; [GPU, Programming] Per-Thread Program Counters; My Bike Accident - Looking Back One Year; [Python] Geographic heights are incredibly easy!; [Cooking] Cookie Recipe; Efficient, Simple, Directed Maximisation of Noisy Function; And for argparse; Bash Completion in Python; [Computing] Configuring Github Jekyll Locally; [Maths, Link] The Napkin Project; You can Masquerade in Firewalld; [Bike] Servicing Budget (Spring) Forks; [Crypto] CIA Internet Comms Failure; [Python] Cute Rate Limiting API; [Causality] Judea Pearl Lecture; [Security, Computing] Chinese Hardware Hack Of Supermicro Boards; SQLAlchemy Joined Table Inheritance and Delete Cascade; [Translation] The Club; [Computing] Super Potato Bruh; [Computing] Extending Jupyter; Further HRM Details; [Computing, Bike] Activities in ch2; [Books, Link] Modern Japanese Lit; What ended up there; [Link, Book] Logic Book; Update - Garmin Express / Connect; Garmin Forerunner 35 v 230; [Link, Politics, Internet] Government Trolls; [Link, Politics] Why identity politics benefits the right more than the left; SSH Forwarding; A Specification For Repeating Events; A Fight for the Soul of Science; [Science, Book, Link] Lost In Math; OpenSuse Leap 15 Network Fixes; Update; [Book] Galileo's Middle Finger; [Bike] Chinese Carbon Rims; [Bike] Servicing Shimano XT Front Hub HB-M8010; [Bike] Aliexpress Cycling Tops; [Computing] Change to ssh handling of multiple identities?; [Bike] Endura Hummvee Lite II; [Computing] Marble Based Logic; [Link, Politics] Sanity Check For Nuclear Launch; [Link, Science] Entropy and Life

© 2006-2017 Andrew Cooke (site) / post authors (content).

Garmin Forerunner 35 v 230

From: andrew cooke <andrew@...>

Date: Fri, 10 Aug 2018 08:09:12 -0400

These are my initial impressions of a Forerunner 35 after having used
a 230 for some time.

The Forerunner 230 had a huge impact on my cycling - it was the first
GPS or HRM device I owned and key to the wonderful worlds of Strava
and structured training.  When it was damaged in an accident I looked
at what I actually used on the watch and felt that a model 35 would
probably be sufficient as a replacement.

I received the 35 yesterday, so these are my initial impressions on the
physical construction, appearance, and software.  I haven't used it on
a ride yet (decent rides are still several months off, as I slowly
recover from the same accident that damaged the old watch).

Let's start with the watch as a physical object.  The face is a
rounded square, while the 230 was round.  Both look attractive to me -
both look like "sports watches" rather than the newer aesthetic that
Garmin seems to be moving towards (metal bezels and a "someone with no
taste might think this is classy" appeal).  Buttons are slightly
easier to find and use on the round face, but that may be just
experience / practice.  The strap on the 35 seems thinner and
"stretchier" than on the 230.  This may be so that the LEDs on the
back of the 35 make better contact with the skin to measure the heart
rate (more on that later) - it's more annoying to put on because the
strap is floppy and the loop that holds the "free end" is tight.

The 230 had 5 buttons, while the 35 has only 4.  This is annoying -
there is no way on the 35 to move "up" when selecting from menus (or
selecting numerical values).  If you miss your aim you have to
laboriously loop round.

The screen of the 35 is light grey LCD when powered off, which was a
surprise - the 230 looks black.  But when powered on the LCD of the 35
is (usually) "reverse video" so looks similar to the 230.  Some
screens are normal LCD, though, and look uglier.  Also, the 35 may
have slightly lower resolution (looks a little blockier).  I have not
missed the "colour" of the 230 at all (a feature that always seemed
pretty useless).  The body of the 35 is thicker, I think (I don't have
the 230 with me as I type this, so everything about that is from
memory) to include the LEDs.

Both watches are light and comfortable, although I prefer wearing the
watch looser than is recommended with the 35 heart rate sensor.  Both
watches appear to use the same USB connector (a "clothes peg" clip at
the watch end).

Maybe the largest difference between the two watches is the software.
The 35 appears to have completely different software to the 230, which
hints at how they are seen as different products.  The 35 is much
less customizable than the 230.  For example, on the 35 I can find no
way to set which profiles are available, but the previously used
profile is taken as default.  The number of screens is limited (2),
their format does not seem to be variable (3 fields only), and the
variety of values that can be displayed on the screens is reduced.  So
I can find no way to display altitude (from the GPS) or compass
direction (maybe the 35 has no internal compass).

In fact, this is my biggest disappointment with the 35 - I use both
compass and altitude when navigating new routes with contour maps.
Since this is a an obscure, out-dated pass-time I guess it won't affect
most people.

On the plus side, the functionality that the 35 does have is easier to
use.  It was obvious how to set an alarm on the watch, for example
(something that must be possible with the 230, but that I had never
worked out how to do).

When used "as a watch" the 35 measures heart rate automatically.  The
values are generally OK, although I have seen some odd numbers and
it's possible that they trend a little low (after wearing it overnight
it has my average resting heart rate as 39, which seems odd, since I
have done little exercise this last 5 months and my minimum a year ago
- when in much better shape - was 37, according to a medical device
worn for 24 hours).

As I said above, I prefer to wear my watch loose.  When I try this
with the 35 it appears to continue to measure pulse rate (even when on
the inside of the wrist).  So perhaps tightness is not so important.
Anyway, I will probably continue to use my old chest strap when on the

Also, the 35 appears to have a bunch of "lifestyle" features.  This
morning (while in bed, asleep, recovering from a 31 hour trip from S
America to the UK) it beeped at me and told me to "start moving".
Easily visible from the front screen is a step count and a calorie
count (no wonder so many people post to Reddit asking about calorie
use - it's presented like something absolute and reliable, rather than
some random number pulled out of Garmin's ass).

So, how to summarise the differences?  The 35 feels less
"professional" than the 230.  Less like it's intended for one specific
exercise, and more for "general fitness".  The lack of customization,
the extra "lifestyle" features, integrated HRM, and the easier to use
but simplified interface all point in this direction.  Which is all
consistent with how it's promoted and sold by Garmin.

But for the basic use case I want - tracking rides - I think it will
work.  I see no reason why the GPS will not work, or the HRM.  I
probably won't use it day-to-day as a watch, though (I didn't use the
230 this way either) - the HRM makes it bulky and the extra "lifestyle
features" are annoying.


Update - Garmin Express / Connect

From: andrew cooke <andrew@...>

Date: Fri, 10 Aug 2018 10:09:07 -0400

Using Garmin Express and Connect (or, presumably, the phone app) you can:

 * Disable many of the lifestyle features (but not step count)

 * Set the heart rate zones you want manually

 * Have up to 4 display screens (but always 3 fields, and with only
   the limited choice of information)

You can also disable the HRM although I haven't done so (yet...).


Further HRM Details

From: andrew cooke <andrew@...>

Date: Mon, 10 Sep 2018 17:15:54 -0300

I've been using the 35 for some time now, on rides of up to an hour
(still recovering from the accident - I guess it's not explained
above, but the 230 was damaged when a car hit me, breaking my leg and
various other bones).

It works just fine and the step counter has turned out to be useful as
part of assessing how much walking I can manage.

However, the wrist-based HRM is not good for me on the bike.  I wear
the watch pretty loose (against advice), so this may be expected.  The
big problem, really, is that it doesn't stop working, but instead
gives completely incorrect values.

So, using the wrist HRM on a recent ride, I never left Z2 (according
to the watch).  With the chest HRM I was in Z3 and sometimes Z4.  That
is appallingly bad (these were very similar rides - same route,
similar times).

HRM during the night does seem to be accurate - it seems to be
tracking my minimum resting HR quite well (the low values I mentioned
above went away after some time).

In conclusion: with a bike, at least if you wear the watch loosely,
you also need a chest HRM.


Comment on this post