We are meant to present on the 16th, so we still have one week for push our project as much as we can. This means parallel work on the project process, the information gathering for the video and thinking on a layout for the slide.
COMPLETED
- Read torque whith the 2 half bridges strain gauges from a bike crank
- Milled the pcb for Oled and bluetooth conected display
- 3D printed screen case (1st prototype version)
- Start thinking on the layout of the electronics on the crank and posible cases
TO BE COMPLETED
- mount everything on the rear of the crank bike
- Connect and comunicate the arduino nano+bluetooth module (Brain) with the oled+bluetooth (Display)
- Display real time values on the screen
- Redesign the 3d printed case to better fit the electronics of the display and if time mould it and cast it for waterproufing
- Design and fabricate the crank electronic case, ideally with moulding and casting too for same reasons and for better protection against hit and bumps.
- Implement the hall effect sensor on the code for reading power.
Thankfully I am still fairly fast with 3D design, so the idea will be to design the new 3d printed elements and send them to the printer as soon as posible. While the printer works I will work on the bluetoooth communication and display show that has been given load of troube, but once I figure it out everything should piece together.
I also think that if I run out of time for moulding and casting, I will leave the screen case as 3D printed and do a acrilic laser cut case for the crank. I know is not ideal, but in a spiral development is better have a fair casing for prototiping that to leave the electronics unprotected. Hopefully I will have time for mould and cast one of those items.
At this point and after having read so much about straing gauges during the whole course I am pretty happy I have been able to read torque with them. I have also, suppousily have been able to apir my bluetooth devices (even I havent been able yet to send information and having it displayed on the screen).
The 3D printed case I have done for the screen doesn't really fit right now, but is not as far from it as I have originaly expected for the first print. I have been having lot of trouble sending info from the arduino nano to the attiny 85 displey via bluetooth or any other mean, but I am hopeful it will. I haven't been able to understand the initial board I was going to use, Nrf52832 which has both a microcontroller and a multiprotocol chip. I was able to interact with the breakout board with my phone, as to turn on and off a led, but I couldn't use it to transmit data via bluetooth. The info about this chip is also more complex for me right now to get it on time, so I have abandoned it for my final project prototype.
How does ANT + comunication works? Even I have abandoned for a while the Nrf52832 chip board, I did it because of my inability to get the bluetooth working. I still haven't started to think about the ANT+ communication. In a device like mine is very important to be able to comunicate with as much sport watches as posible, as lot of people use them as displais intead of having an specific screen for the bike.
I have learnt a lot about strain gauges, something that I was completely unaware before fab academy. I have also learnt about Open Source devices and how a useful device like this can be shared as an open and reproductible item. I have learnt about serial communication, tx rx, and how to use serial with ATtinies. I have learn a little how to filter info through the web in the search of what you are looking for and how most of the doubts can be solved if you looked a little bit around the web.
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