SRM for idiots: a question

[Climb01742]

ok, my SRM is finally up and running and talking to my laptop (merci to the good senor and 'bama boy). but i have a question:

to start recording a ride, you press MODE then SET (say, at the beginning of a ride). then to stop recording (like at the end of ride), press SET. so how do you record separate intervals within a ride? would you press SET to stop recording the first interval, then press SET again to start the second? and just repeat hitting SET twice to record separate intervals?

and what would happen if, at the beginning of the ride, you just hit MODE to wake the SRM up, but didn't hit SET? would it record data or just display data until you hit SET?

it seems like there are times you'd want to record your whole ride, and other times just record intervals within the ride?

your seriously techno-challenged climb says "thanks" in advance.

[DfCas]

to send you here.

http://lists.topica.com/lists/wattage/read

This is where the watt trainers reside and some there even write software for such things.Some scary bright people on that list.


dan

[ada@prorider.or]

well the set botton is for calibration
if you do not do that it would take the set number from the ride before

as the record begins automatic when you start riding

it has no influence if you pusch mode becuase that's only for the display

i would do it simpel and just calibrate for each ride
and do selections in computer

we in the early days have done experiment with a start stop botton for a interval or a certain part of test
but afterwords is good as on the bike
becuase you would normaly check the ride in the computer or you just want it as a extremly expensive speedo meter

[Buddha]

ok, my SRM is finally up and running and talking to my laptop (merci to the good senor and 'bama boy). but i have a question:

to start recording a ride, you press MODE then SET (say, at the beginning of a ride). then to stop recording (like at the end of ride), press SET. so how do you record separate intervals within a ride? would you press SET to stop recording the first interval, then press SET again to start the second? and just repeat hitting SET twice to record separate intervals?


and what would happen if, at the beginning of the ride, you just hit MODE to wake the SRM up, but didn't hit SET? would it record data or just display data until you hit SET?
it seems like there are times you'd want to record your whole ride, and other times just record intervals within the ride?

your seriously techno-challenged climb says "thanks" in advance.

At the begining of the ride, with the head unit woken up, you should press MODE and SET at the same time. This will get you to the calibration numbers. With no tension on the pedals, let the upper number settle then press SET, then hit the MODE putton and you are good to go. Everything starts to record.
At this point hitting the SET button will start an interval. Hitting the SET button again will end the interval. While "in" a interval the numbers on the screen will be for that interval.

If you don't go throught the calibration, your watts may be off.

Also make sure you put the proper slope number in the head unit with your laptop.

[Too Tall]

Close....

With the head unit cabled up:
1. Spin the cranks backwards a few revs. This will wake up the unit and establish initial slope calibration.
2. NOW press mode + set and the same time and you will see two numbers. Wait a couple seconds for the numbers to settle down NOW press Set and you have corrected the slope for the ride...unless the temp. changes alot.
3. You can just start riding...the unit is always recording OR once you start riding you can press SET at any time to record an interval. It NOT necessary to press set and begin an interval unless you want to mark a specific portion of the ride...because the unit is ALWAYS on :) now that you have pressed set to mark the start of an interval...pressing set again will MARK the end of the interval and you can see it later as a BLOCK of data. This is esp. useful at the beginning of a set of intervals eg. 3X5s so that later on when you dowlonad you can see where the intervals began. I find it useful to only mark the first and last interval (of a series) using set button and than using my PEAKS software "block" the intervals and assign them labels...using PEAKS. (less work).
4. After the ride OR at whatever point you want to clear the display you can press SET + PRO at the same time to clear the display. This will NOT clear your stored data....repeat...NOT. Sometimes I leave the SRM on my bike for a few days...or until the battery goes dead...and will clear each days display so that I'm looking at fresh numbers....the unit will store your data in a time:date correct fashion for as long as it has memory to do so. Don't be tempted to set the SRM to anything more than 5 second data collection or your data will not be as good.

Than help? beers:beers:cold:ones.

[ada@prorider.or]

[QUOTE=Too Tall for the ride...unless the temp. changes alot.

.[/QUOTE]

well do not agree
the temp is independant of calibration

example you start in valley 50 degrees celcuis
and comup the mountain let say
-10 degrees (stelvio hampsten)
the you have a temp deifferance in 60 degrees
so that influence your watts

in your case what do you do then
get of your bike and calibrate

i had the situation with andy hampsten in giro
so it can happen

but the calibration is for measuring it local frequentie on the bike
and the temp is compensated in the chip
and why not set data bigger the 5 seconds it only average the watss so it make now differance
it only refresh you screen slowly so more stable
and
what is the differance the if you have average of
10000* .001 second 250 watt
or
1 time 10 second 250 watt

sorry i do not see the differance
and

it is not the case that it measure with this
time period
only write's the date away
in that time period

but again you see more if you have each data point
at .001 tehn 10 seconds
but the average stays the same
its only what yo want to see and measure
if you want too see how blood pressure changes on a steep track with high speed makes no sense in do that in 10 seconds time interval
but make sence in 0.001 time interval

hope you get the idea





:banana: :banana:

[Buddha]

well do not agree
the temp is independant of calibration

example you start in valley 50 degrees celcuis
and comup the mountain let say
-10 degrees (stelvio hampsten)
the you have a temp deifferance in 60 degrees
so that influence your watts

in your case what do you do then
get of your bike and calibrate

i had the situation with andy hampsten in giro
so it can happen

but the calibration is for measuring it local frequentie on the bike
and the temp is compensated in the chip
and why not set data bigger the 5 seconds it only average the watss so it make now differance
it only refresh you screen slowly so more stable
and
what is the differance the if you have average of
10000* .001 second 250 watt
or
1 time 10 second 250 watt

sorry i do not see the differance
and

it is not the case that it measure with this
time period
only write's the date away
in that time period

but again you see more if you have each data point
at .001 tehn 10 seconds
but the average stays the same
its only what yo want to see and measure
if you want too see how blood pressure changes on a steep track with high speed makes no sense in do that in 10 seconds time interval
but make sence in 0.001 time interval

hope you get the idea





:banana: :banana:

According to the SRM people, when on a ride with a temp fluctuation like you mentioned, you should re calibrate. It has to do with the epoxy used to hold the strain gages. SRM's do not self calibrate like a Power Tap.

[ada@prorider.or]

According to the SRM people, when on a ride with a temp fluctuation like you mentioned, you should re calibrate. It has to do with the epoxy used to hold the strain gages. SRM's do not self calibrate like a Power Tap.

well i get off my bike then during the race and recalibrate

expoy that hold stain gauges not able to be stable
at temp range?
well i want to see that expoy glue
remember ther are only little spots
becuase the strain gauge is is the mesauring device
other wise you not measurring the strain but the elasticity of the glue

[ada@prorider.or]

Ideally, we would like the resistance of the strain gauge to change only in response to applied strain. However, strain gauge material, as well as the specimen material to which the gauge is applied, will also respond to changes in temperature. Strain gauge manufacturers attempt to minimize sensitivity to temperature by processing the gauge material to compensate for the thermal expansion of the specimen material for which the gauge is intended. While compensated gauges reduce the thermal sensitivity, they do not totally remove it.
By using two strain gauges in the bridge, the effect of temperature can be further minimized. For example, Figure 5 illustrates a strain gauge configuration where one gauge is active (RG + DR), and a second gauge is placed transverse to the applied strain. Therefore, the strain has little effect on the second gauge, called the dummy gauge. However, any changes in temperature will affect both gauges in the same way. Because the temperature changes are identical in the two gauges, the ratio of their resistance does not change, the voltage VO does not change, and the effects of the temperature change are minimized.



Figure 5. Use of Dummy Gauge to Eliminate Temperature Effects

[ada@prorider.or]

http://www.grc.nasa.gov/WWW/sensors/PhySen/Strain_a.htm

[Climb01742]

whoa. normally i feel dumb. now i really feel dumb. ;)

thanks tootall and buddha! and cees, for the small bit my small brain understood, thanks too!

what i need is for steve jobs to build a powermeter: the ipodmeter! :beer:

[Too Tall]

Climb-meister - pick up the bannana and call me. Dewd, don't be fooled by imitators you've got the good stuff.
Cees - You think too much :rolleyes: It is a good thing but gee golly you have a BIG brain! For what it is worth, if I store the SRM head unit indoors than leave for a cold bike ride it is smart for me to set the bike outdoors for 10 mins. before I ride or calibrate the SRM.

[ada@prorider.or]

Climb-meister - pick up the bannana and call me. Dewd, don't be fooled by imitators you've got the good stuff.
Cees - You think too much :rolleyes: It is a good thing but gee golly you have a BIG brain! For what it is worth, if I store the SRM head unit indoors than leave for a cold bike ride it is smart for me to set the bike outdoors for 10 mins. before I ride or calibrate the SRM.

well i wrote special software for srm
so i had to go into it thats all

[Too Tall]

See? See? Your brain is TOO big ;) hehe.
Serioulsy I hear yah regards a reasonable method to "self-calibrate" the SRM strain guages. Good thinkin' Abe Lincoln. What's your thoughts about the FSA / SRM marriage? I like the FSA company and their products are working well so this should be a good thing?

[ergott]

Sheesh! You'd think this guy, like, wrote some of the software for the SRM. Oh, wait, he did.

well do not agree
the temp is independant of calibration

example you start in valley 50 degrees celcuis
and comup the mountain let say
-10 degrees (stelvio hampsten)
the you have a temp deifferance in 60 degrees
so that influence your watts

in your case what do you do then
get of your bike and calibrate

i had the situation with andy hampsten in giro
so it can happen

but the calibration is for measuring it local frequentie on the bike
and the temp is compensated in the chip
and why not set data bigger the 5 seconds it only average the watss so it make now differance
it only refresh you screen slowly so more stable
and
what is the differance the if you have average of
10000* .001 second 250 watt
or
1 time 10 second 250 watt

sorry i do not see the differance
and

it is not the case that it measure with this
time period
only write's the date away
in that time period

but again you see more if you have each data point
at .001 tehn 10 seconds
but the average stays the same
its only what yo want to see and measure
if you want too see how blood pressure changes on a steep track with high speed makes no sense in do that in 10 seconds time interval
but make sence in 0.001 time interval

hope you get the idea





:banana: :banana:

[ergott]

See? See? Your brain is TOO big ;) hehe.
Serioulsy I hear yah regards a reasonable method to "self-calibrate" the SRM strain guages. Good thinkin' Abe Lincoln. What's your thoughts about the FSA / SRM marriage? I like the FSA company and their products are working well so this should be a good thing?

Only good if they maintain a comparative high level of stiffness. It is supposed to be the same weight as a non SRM Dura Ace crankset. Very light, hopefully as stiff as the DA version. To expensive to buy. At that point, I would want to be sponsored and get that kind of bling for free.