#6 - lack of bicycling

A project log for Open Bicycle Computer

Arduino based bicycle computer using open hardware and software logging data on SD card and JS web interface using USBOTG and USBHID

davedarkodavedarko 06/01/2015 at 10:336 Comments

You probably know how it is with projects - you're motivated at some point and then again totally lost focus and interest. And necessity is the mother of invention. This is not an excuse log. I'll always take a look at my projects and think about everyone for a minute.

There is a professional way to make this project and a diy/hackish-way to do it. This should probably be made with BTLE and be connected to your phone, but this would compromise my initial - off the phone - concept. I still have a BTLE dev kit - the wunderbar - with 6 sensor boards and one "mother"board somewhere and I feel like I owe them a project since I've won this and it's probably what they expected when they handed them out (because reasons). It's not that easy to hack, I guess. I'd have to work with the onboard BTLE chip and there are more people that are used to "work" with arduino.

I need a quick hacked together prototype to start writing some more code though. It should be something anyone can build with a few parts - basically a LiPo cell, a 5V boost converter and an arduino connected to a 1602 LCD character display with a hall effect sensor connected. I'm not happy with 5Vs though. the battery power should be measured with the arduino, too. This is a total waste of money in comparison to a 5 dollar computer and basically what I've achieved already. Next step would has to be logging. That's the killer-app / the pitch. Am I going in the right direction?

This feels like two projects! Damn! One is easy to hack together but not efficient, one is efficient but not easy to hack.

What should be the key point here?


jaromir.sukuba wrote 09/21/2015 at 19:07 point

One gauss is 0,1 militesla (1G=0,1mT), so you can compare it.

EDIT: Damn enter to send message! Recently I needed some hall sensor, so I bought a few with slightly different sensitivities. The first one I picked was good and gave clear repeatable response from a half of centimeter to small (10mm dia, 1mm thick) neodymium magnet from ebay, so I was set. I'd say that the particular one I highlighted before would be OK.

EDIT2: Now I found it, it was this sensor

  Are you sure? yes | no

jaromir.sukuba wrote 09/21/2015 at 12:28 point

Choose the efficient one.

What you need 5V for?

  Are you sure? yes | no

davedarko wrote 09/21/2015 at 12:31 point

I think it was the hall effect sensor.

  Are you sure? yes | no

jaromir.sukuba wrote 09/21/2015 at 12:35 point
Well, times has chaged since the last update ;-) You can buy hall sensors with 2,7V minimal Vcc nowadays For 5V LCD you can use the old trick

  Are you sure? yes | no

davedarko wrote 09/21/2015 at 14:57 point

the OLED display is 3V - 5V - it really was only because of the sensor... 

  Are you sure? yes | no

davedarko wrote 09/21/2015 at 15:09 point

any tips on the resolution of the sensors? I can get +- 140G , +-55G and +-12mT and I have no idea about hall sensors.

  Are you sure? yes | no