#3 thoughts about power

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 08/04/2014 at 09:092 Comments

Since mr.jb.swes project Multicharger is all over my feed, (congrats!) and this page too, I'm thinking far ahead of my timeline. To keep it simple I want a single cell setup, boosting the voltage up to 5V. The hall effect sensors are only working with 5V so I started my first compromise, which turned out to be good, because this way I can monitor the power from the cell with an analog in pin of the arduino and everything gets more tinkerer-friendly. Now I need a way to get the dynamo voltages down to 3.5V to charge the LiFePo accordingly. Sounds overly complicated to convert from 6V to 3.5V to 5V but a battery comes in handy when you are standing because of a traffic light in the nights and you don't want your lights (or computer) to go off.


Stefan-Xp wrote 08/04/2014 at 09:21 point
Have you thougth about using another Hallsensor?

f.ex. operates from 3V .. 32V
The SMD form-factor could be a little turnoff but okay :D
Best regards, Stefan

  Are you sure? yes | no

davedarko wrote 08/06/2014 at 14:56 point
Sorry, haven't seen this comment before...

the 5V boost gives me the advantage of a stable power source so that I can measure the battery capacity (using Aref vs. Ain will always give you 1024 when vcc comes directly from the battery) and also be over the charging voltage and use really cheap arduino clones for 2 euros each.

  Are you sure? yes | no