Cycling and bicycle discussion forums. 
   Click here to join our community Log in to access your Control Panel  


Go Back   > >

Bicycle Mechanics Broken bottom bracket? Tacoed wheel? If you're having problems with your bicycle, or just need help fixing a flat, drop in here for the latest on bicycle mechanics & bicycle maintenance.

User Tag List

Reply
 
Thread Tools Search this Thread
Old 05-29-07, 06:44 AM   #1
freeranger
Senior Member
Thread Starter
 
freeranger's Avatar
 
Join Date: Jun 2005
Location: Kentucky
Bikes: 06 Lemond Reno, 98 GT Timberline mtn.bike
Posts: 1,016
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Cyclometers and Sun.........

Evidently, cyclometers and sun do not mix well. Went for a ride yesterday, and left the bikes, with cyclometers on them, in the back of my truck, while we took all the gear in, took the dogs down the street for a walk, grabbed some ice water, etc. Was probably around 20 minutes they sat there. Upon unloading the bikes, noticed one of them (an inexpensive wireless house brand) had all the display showing, every function, zero's for all of the numbers, whatever could appear on the screen did appear on the screen. Was hoping it would work after it cooled down, and luckily, it does. So, don't leave your cyclometers out in the sun for long periods of time. The only thing I can figure is that LCD's must work by heat generated by electrical impulses?? Just wondering, figured that the LCD's being heated up brought them up on the display.
freeranger is offline   Reply With Quote
Old 05-29-07, 07:11 AM   #2
DMF 
Elitist Troglodyte
 
DMF's Avatar
 
Join Date: Jun 2006
Location: Dallas
Bikes: 03 Raleigh Professional (steel)
Posts: 6,924
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Quote:
LCD's must work by heat generated by electrical impulses??
Nope. For the types of displays used by cyclometers, the presence of a small electrical field changes how the material polarizes the light passing through it, making the area look different.

Integrated circuits have an upper temperature limit above which they cease to function. Military-grade logic is closely spec'd and tested for this, but consumer stuff is sort of hit-or-miss, with a much lower designed temperature range. Also, battery voltage increases as the cell gets hotter, and may have caused the power circuit to cut it off, or the higher voltage may have cause a reset.

Data saved in non-volatile memory may or may not be affected by any of this.
__________________
Stupidity got us into this mess - why can't it get us out?

- Will Rogers
DMF is offline   Reply With Quote
Old 05-29-07, 07:52 AM   #3
operator
cab horn
 
Join Date: Jun 2004
Location: Toronto
Bikes: 1987 Bianchi Campione
Posts: 28,306
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Quote:
Originally Posted by DMF
Data saved in non-volatile memory may or may not be affected by any of this.
Well yes, that are the two choices
operator is offline   Reply With Quote
Old 05-29-07, 08:09 AM   #4
DMF 
Elitist Troglodyte
 
DMF's Avatar
 
Join Date: Jun 2006
Location: Dallas
Bikes: 03 Raleigh Professional (steel)
Posts: 6,924
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
There are three states of information: positive, negative, and unknown.

When diagnosing a problem, knowing that a symptom has no diagnostic value is as real and valuable information as knowing that the symptom state is determinate of X.

Smarm, otoh, has no value.
__________________
Stupidity got us into this mess - why can't it get us out?

- Will Rogers
DMF is offline   Reply With Quote
Old 05-29-07, 09:55 AM   #5
noisebeam
Al
 
noisebeam's Avatar
 
Join Date: Jun 2004
Location: AZ
Bikes: Cannondale SuperSix, Lemond Poprad. Retired: Jamis Sputnik, Centurion LeMans Fixed, Diamond Back ascent ex
Posts: 14,114
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 430 Post(s)
Standard LCDs don't work in high (~>120F) heat. The sun on the unit can easily get it to to that range.

The computer still will work, but the display wont.

In the summer for my ride home the display always stops working. Once home and cooled down all the correct data from the ride is available.

Al
noisebeam is offline   Reply With Quote
Old 05-29-07, 09:56 AM   #6
tsl
Plays in traffic
 
tsl's Avatar
 
Join Date: May 2006
Location: Rochester, NY
Bikes: 1996 Litespeed Classic, 2006 Trek Portland, 2013 Ribble Winter/Audax
Posts: 6,961
Mentioned: 5 Post(s)
Tagged: 0 Thread(s)
Quoted: 34 Post(s)
Quote:
Originally Posted by freeranger
an inexpensive wireless house brand
That's all the troubleshooting you need, right there.
tsl is offline   Reply With Quote
Old 05-29-07, 10:39 AM   #7
supcom
You need a new bike
 
supcom's Avatar
 
Join Date: Aug 2002
Bikes:
Posts: 5,433
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
I've never had a problem with a bike computer in the sun while riding. I have had a computer reset itself while being stored in a hot car. It wasn't a cheap brand, either.
supcom is offline   Reply With Quote
Old 05-29-07, 10:40 AM   #8
top506
Death fork? Naaaah!!
 
top506's Avatar
 
Join Date: Nov 2005
Location: The other Maine, north of RT 2
Bikes: '71 Gitane Super Corsa, '73 Atala Giro d'Italia, '73 Schwinn Super Sport, '76 Viscount Aerospace Pro, '81 Miyata 710, '81 Lotus Classique, '84 Ross Signature 290s, '85 Miele Gara, '87 Miyata 512, '89 Centurion Ironman, many more
Posts: 3,807
Mentioned: 5 Post(s)
Tagged: 0 Thread(s)
Quoted: 37 Post(s)
The instruction booklet of the cheapo Nashbar C-comp specificly warns against leaving the unit in direct sunlight.
Top
__________________
You know it's going to be a good day when the stem and seatpost come right out.
top506 is offline   Reply With Quote
Old 05-29-07, 11:46 AM   #9
cccorlew
Erect member since 1953
 
cccorlew's Avatar
 
Join Date: Dec 2006
Location: Antioch, CA (SF Bay Area)
Bikes: Roubaix Expert, Motobecane Ti Century Elite turned commuter, Cannondale F500 Mtn bike, Some old French thing gone fixie
Posts: 6,786
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 9 Post(s)
Didn't it all show up correctly after it cooled off? LCDs do tend to show every line when too hot, but mine always returned to normal. It isn't sun, it's heat. Usually just riding it enough to cool 'em off.
cccorlew is offline   Reply With Quote
Old 05-29-07, 02:05 PM   #10
Volfy
Senior Member
 
Join Date: Mar 2007
Location: Gulf Coast
Bikes:
Posts: 263
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
If your cyclocomputer craps out after been in the sun for 20mins this time of the year, it's time to look for a new one. Standard LCDs are typically good for up to 50degC. High temp version go up to 100+degC. Cyclocomputer makers should know that these things are inherently outdoor duty devices and will be under the sun for extended periods.
Volfy is offline   Reply With Quote
Old 05-29-07, 02:17 PM   #11
noisebeam
Al
 
noisebeam's Avatar
 
Join Date: Jun 2004
Location: AZ
Bikes: Cannondale SuperSix, Lemond Poprad. Retired: Jamis Sputnik, Centurion LeMans Fixed, Diamond Back ascent ex
Posts: 14,114
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 430 Post(s)
Quote:
Originally Posted by Volfy
If your cyclocomputer craps out after been in the sun for 20mins this time of the year, it's time to look for a new one. Standard LCDs are typically good for up to 50degC. High temp version go up to 100+degC. Cyclocomputer makers should know that these things are inherently outdoor duty devices and will be under the sun for extended periods.
Cyclocomputers exposed to the sun can easily reach 50C. (After all I've cycled in 49C air temps before)

Do you know what voltage/power requirements the non-standard versions require? I don't but I wonder if there are downsides (beyond cost) for using them in small, low power portable units?

http://www.altadox.com/lcd/knowledge...ure_ranges.htm
http://www.pacificdisplay.com/lcd_temp_range.htm

Anyway the 3 different Cateye cyclocomputers I've ever used have all had displays crap out in the summer afternoon.

Al
noisebeam is offline   Reply With Quote
Old 05-29-07, 02:50 PM   #12
kandnhome
Unemplawyer
 
Join Date: Aug 2004
Location: The Natural State
Bikes: 2006 21" Rockhopper
Posts: 459
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Quote:
Originally Posted by DMF

Smarm, otoh, has no value.
I would bear your children were I capable.

But yeah, you wanna have some fun, gather up a bunch of electronics from around your house and put them in the back of your truck on a sunny day, come back in 20 minutes and see what's not broken or damaged. My guess is not much. Also don't put them in the microwave, underwater (esp. while plugged in), or in fire.

Oops, that's kinda smarmy.

But being in the back of a steel vehicle with a lens over it is not a good thing for the temperature of the LCD. While the ambient might only be 30-40 deg C, add in reflection from the steel truck bed (try touching one on a hot day!) and focused sunlight from the lens over the screen, and it'd be pretty easy to see temps close to 90 deg C. Way beyond the failure point for most consumer-grade electronics components.
kandnhome is offline   Reply With Quote
Old 05-29-07, 02:54 PM   #13
Volfy
Senior Member
 
Join Date: Mar 2007
Location: Gulf Coast
Bikes:
Posts: 263
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Quote:
Originally Posted by noisebeam
Cyclocomputers exposed to the sun can easily reach 50C. (After all I've cycled in 49C air temps before)
Do you know what voltage/power requirements the non-standard versions require? I don't but I wonder if there are downsides (beyond cost) for using them in small, low power portable units?
http://www.altadox.com/lcd/knowledge...ure_ranges.htm
http://www.pacificdisplay.com/lcd_temp_range.htm
Anyway the 3 different Cateye cyclocomputers I've ever used have all had displays crap out in the summer afternoon.
Al
The LCDs we routinely spec out at work go -30 to +85C. Our stuff have to work in the middle east desert as well as Canadian winters. The LCD bias voltage is higher on the extended temp version, but it's to add excitation to the LC for the low temp side, which shouldn't be a concern for cycling. I doubt too many would brave much below freezing. I think high temp tolerance has to do more with the construction of the LCD than the electrical requirements.
Volfy is offline   Reply With Quote
Old 05-29-07, 03:26 PM   #14
ax0n
Trans-Urban Velocommando
 
ax0n's Avatar
 
Join Date: Nov 2006
Location: Lenexa, KS
Bikes: 06 Trek 1200 - 98 DB Outlook - 99 DB Sorrento
Posts: 2,400
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Quote:
Originally Posted by freeranger
Evidently, cyclometers and sun do not mix well. Went for a ride yesterday, and left the bikes, with cyclometers on them, in the back of my truck, while we took all the gear in, took the dogs down the street for a walk, grabbed some ice water, etc. Was probably around 20 minutes they sat there. Upon unloading the bikes, noticed one of them (an inexpensive wireless house brand) had all the display showing, every function, zero's for all of the numbers, whatever could appear on the screen did appear on the screen. Was hoping it would work after it cooled down, and luckily, it does. So, don't leave your cyclometers out in the sun for long periods of time. The only thing I can figure is that LCD's must work by heat generated by electrical impulses?? Just wondering, figured that the LCD's being heated up brought them up on the display.
Actually, the display just activated all the segments due to the heat. Functionally, it would have worked fine. any miles logged with the display overheated would have likely been logged, etc. If the display gets way too hot, the whole LCD will go black. Even hotter, it might have permanent black "blobs" under the display. Hotter still, the display will crack and/or stay black.

This is the opposite of a cyclocomputer display acting really sluggish or failing to "come online" in really cold weather.

The electronics themselves would probably work up past 250 degrees fahrenheit. The watch battery and/or LCD display would fail at a much lower temperature.

In short, your computer wasn't malfunctioning. You weren't paying attention to the "operating conditions" section of the manual, though, either.
ax0n is offline   Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off



All times are GMT -6. The time now is 11:00 PM.