Bicycle Computer #10 – Connecting your Bike Computer to the Cloud

re: Bicycle Computer #10 – Connecting your Bike Computer to the Cloud

freds — Fri, 22 Oct 2010 17:53:12 GMT

Going to have to say something else at this time; but probably have given away enough in my posts at this time.

Back to your project; aviation altimeter setting are frequently updated as they are a safety of flight item. In reference to altimeter setting there a saying "from high to low watch out below!" which means if an airplane flies from a high pressure area to low pressure one (typically bad weather and you can’t see the ground until the last few seconds of flight) if the pilot doesn't update with the local altimeter setting they will be flying lower then they think.

So with local knowledge to detect a front passage you can track the change in settings for McCord, SeaTac, Boeing field, Paine field, etc.

Again back to your project; for an all-day pilgrimage on a long bike ride to say Portland you would want the home application to collect readings along your route for post processing.

re: Bicycle Computer #10 – Connecting your Bike Computer to the Cloud

Colin Miller — Mon, 18 Oct 2010 16:50:31 GMT

Good job freds!!!

Who would have ever thought is was light sensitive. I still have the SCF1000. I may go back a play with it (time permitting). It was a less expensive options. I also have a wireless connection. I have found the ATIS info online for SeaTac so I can update the pressure on startup.

Are you builing a bike computer or something else?

re: Bicycle Computer #10 – Connecting your Bike Computer to the Cloud

freds — Sun, 17 Oct 2010 00:24:09 GMT

I think you gave up on the SCF1000 sensor a bit too soon. I was getting errors similar to yours and got it settle down with stable readings by:

1. The bloody think is light sensitive! You need a cap over it to keep the light from getting to it.

2. It will occasionally throw an error that is 20ft off on a single reading and then return on the next. I use the sensor in fast mode of nine readings a second and the 20ft deviation would in airplane equal a climb or decent of almost 11,000 feet per minute (think fighter). On your bike that would falling down a 20ft cliff in 1/10 of a second. So like any sensor it could do with a sanity check.

3. I added a 6.8uf capacitor across the VCC on the sensor with a 220ohm resister between it and the 3.3v power source. Forget what they call this type of power filter, but after adding this filter the false readings practically went away.

Also when taking long term measurements; check the ATIS at a local airport via the phone before and after. The ATIS reports altimeter settings in inch of mercury (here in the states) a one inch change is about 1000ft in altitude.

I remember your article was concerned with power consumption; I suggest a half or full second of readings every 5-10 seconds.

re: Bicycle Computer #10 – Connecting your Bike Computer to the Cloud

Colin Miller — Thu, 14 Oct 2010 15:51:20 GMT

Thanks Eric. There is a lot of really cool stuff being done wiht NETMF and it is not difficult to get articles out on interesting topics. I have a few ideas percolating and I want to find a better way to keep track of what everyone is doing with the platform. That is one downside to Open Source - we dont necessarily know who all is using it.

re: Bicycle Computer #10 – Connecting your Bike Computer to the Cloud

interlock — Thu, 14 Oct 2010 13:55:36 GMT

Awesome to see your stuff making it to print! I've been following the bike computer blogs and was amazed to see this one in my snail mailbox. Can we expect to see more NETMF stuff front and center on MSDN in general? Maybe even a fifth button of your own on the home page ;-) Great job Colin!