A bicycle computer (speedometer) that shows speed and covered distance on a LCD screen, is supplied by a 3.7V LiPo battery and uses a Reed switch as speed sensor. It doesn't get more complex that that.
ahh, and it fits in the backside of a 16x2 LCD breakout board!.
I have now finished testing the code and also validating the hardware for my bicycle computer; You guys can check the final files (both Arduino firmware and PCB) on the links section of this project.
The last step on transforming this project on a real product is making a nice little case for it. I guess I am just lucky, because this week's hackaday prize giveaway is $50 on 3D-printed parts. This chance came in a nice time, since I have never played with 3D printed objects, and now I have the chance!.
I have already started designing the parts on "123D Design", using examples available in the software's main page (from Autodesk). Great news and great parts designs are to come!.
This week's giveaway is about Teensy! what a lovely choice from the #Had team. these Arduino-compatible (Cortex-M0 powered) little beasts are the choice when you need low power consumption, high speed, processing capability and space reduction. Not to talk about off-the-shelf solution :) .
When I saw Myke's post I knew I needed a Teensy LC for my little bicycle computer. By adding it to my design I believe I will be able to shrink PCB real-state while keeping it modular and Arduino-compatible (all of which are part of the original idea for this project).
In case you have not seen yet, I have added the link to the Github code of my bicycle computer (in the links section of this project). I have also added a link to the board schematics on the same place.
Regarding the project functionality, I have tested it on the bench (using an Arduino to simulate the spin of the bike wheel) and I'm proud to to say it works!.
Next step will be adding communications to the bike computer, so that one can connect its cellphone to it; this is where the hackaday's giveaway comes to scene: they are giving away a bunch of bluetooth LightBlue Bean BLE, which will perfectly fit my needs: these little BLE boards features (besides the obvious BLE) an ATMEGA328, the same processor I am using as the guts of the project! perfect matching :) .
So this week's wish is to get my hands on one of those LightBlue Beans.
Today is a Saturday, so it means this is the making day for me!. I recently got the SMD ATMEGA328P-AU on the mail, so the task for today is assembling and testing the pcb and code.
After an hour (or so) I have finished assembling the PCB, and managed to upload the blink_without_delay sketch to the Arduino (that leaded to the yellow led to blink!). So far so good, the board circuitry is all good, next step is uploading the actual bike_computer firmware to it and start debugging.