A true bike computer

[Hari Krishna]

Hey guys

I built a jig over the weekend to log data about my commutes. It's a Raspberry Pi Zero based system that measures speed, distance and cadence (for now). I'm currently working on integrating an accelerometer into it to operate turning lights and brake lights (and also log data about potholes). One application of the pothole data is to plan the route with least potholes.

Unlike a regular bike computer, it also plots the values when a switch is toggled. Attached are a few pics of my system (including my cadence plot for today morning's ride). It withstood minor splashes and drizzles on my 25 km commutes. 

The structural components are designed by me and built on my homemade 3D printer. It ran for over a full day on a 5000 mah power bank.

P.S.: I can replicate this system for anyone who wants it.

[Opendro]

That is cool, Hari, though I doubt if anybody would be interested in it :-(

[Narayan R]

Hi Hari,

I am interested. Share more details : 

How do you measures speed, distance and cadence ?

Pretty cool again.

Can you share the days log ?

Thanks again.

With Regards,

R Narayan

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[Hari Krishna]

Hey Narayan

It computes speed, distance and cadence like any other bike comp, using a hall effect sensor and magnets. I 3D printed a magnet holder for the pedal arm. It's quite simple to hook up an LCD display to it make it function as a regular bike comp as well. I can help with 3D printing that as well.

I'll share the log with you privately.

[mkonchady]

Nice ... would be interesting to know how your set up compares to a Wahoo cadence sensor + Smart Phone.

Wahoo has a speed and cadence sensor that transmits speed / distance data ivia bluetooth to a smart phone and can be integrated with GPS data.

While the raspberry pi is efficient and uses a few watts of power, the smart phone is even more efficient and probably uses a fraction of a watt. Without a screen or leds, the raspberry pi is probably just as efficient as a smart phone.

On a smart phone, there is a lot that can be done with GPS alone – however, speeds and distance measurements have inaccuracies. While a cyclocomputer gives accurate real time distance and speed is measured at a high resolution (many times a second), most cyclocomputers don’t store the information.

A smart phone using GPS measures distance at a lower resolution (once in 5 or 10 seconds) and is inaccurate. If a smart phone and a cyclocomputer can be synchronized to the same time, then we will have accurate distance and speeds.

Unfortunately, pot hole data keeps changing – new pot holes emerge and old pot holes are hopefully fixed. Anyway, your data will show the rate at which BBMP is fixing pot holes.

--Manu Konchady

On Thursday, November 2, 2017 at 8:56:08 PM UTC+5:30, Hari Krishna wrote:

[Prashanth Chengi]

This solution is always going to be clunky and seemingly not as clean a solution as something prepackaged (obviously), but there are a few areas where this setup is simply awesome:

1. This is a Raspberry Pi, running a full-blown Linux, instead of a heavily modified environment like Android.

2. You don't have to mess around with Android app development, for custom solutions; a bash/python script or a few lines of C code and you are in business.

3. With operating system options like Arch Linux for Arm, you get access to really cutting edge distributions, meaning driver support for devices which won't be supported in a long time (or ever) on platforms such as Android. 

What this is virtually without a match in, is as a testbed for data extraction. What kind of data? That's limited to ones imagination. From pothole census to power analysis, anything's possible. You could rig up a bike with this kit, and some additional equipment, like a power meter (awesome source of data) and get a bunch of seasoned bikers to hit a carefully selected/prepared course, to see how different riding techniques/styles seem to affect power delivery.  You can make it even more interesting if you can throw in some motion capture sensors into it. Check this endgadget article for inspiration:
https://www.engadget.com/2016/12/13/disneys-real-time-motion-capture-tech/

The Pi family of computers are really excellent and most people are amazed how much useful computing is possible on a device so small; Though many modern smartphones often pack more number-crunching abilities than a Pi, their abilities are severely curtailed by the extremely restrictive operating systems they run. The Pi, on the other hand doesn't have these limitations and has more than enough juice to run multiple sensors and crunch the data, making it supremely powerful, in experienced hands. This platform is a data porn lover's dream (wet, if captured in the rain! :D). Have fun, Hari, and keep us in the loop. 

Start a github repo, with an exhaustive component inventory and directions on how to replicate your setup. Others including me could then contribute scripts, or enhance documentation. Will be fun!

/Prashanth

--

[Alex J V]

> Start a github repo, with an exhaustive component inventory and directions on how to replicate your setup. Others including me could then contribute scripts, or enhance documentation. Will be fun!
Agree !

ᐧ

Alex J V

@alexjv89

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[berkeleydb]

Wow Hari... this is pretty cool. I didn't see a screen in the pics (or i missed it). Is there any immediate visual readout? Or it's currently a logger with data to be viewed later?

Curious to know about the turn signals + accelorometer. I can understand the accelorometer controlling the tail light. But for turn signals, the signal needs to be given well before the turn to give traffic sufficient notice about the intent to turn. Giving a turn signal when one starts to turn (as detected by the accelorometer) is very late... though that is what many Indian drivers do. ;)

-{db}.

[itisravi]

Cool project. I must say though, that the Pi is probably an overkill for what could have been done with a micro controller. But if you did manage to get the pi zero for 5USD, it doesn't matter. :-)

-Ravi

On Thursday, November 2, 2017 at 8:56:08 PM UTC+5:30, Hari Krishna wrote: