Mike, good news that you are on your way.
To your questions.
I use a single cell (1.2V Accu or 1.5V Batty) as power source. The TPS61220 will boost it up to 3.3V. So VCC is 3.3V since the display needs 3.3V, no additional voltage converters are needed.
- TPS boost converter TPS61220 http://www.ti.com/lit/ds/symlink/tps61222.pdf
- The RTC is a MCP7941 http://ww1.microchip.com/downloads/en/DeviceDoc/20002266F.pdf
- Hall sensor is a SS443A http://www.mouser.com/ds/2/187/honeywell-sensing-ss400%20series-product-sheet-00905-947400.pdf
About the detecting of the direction... why do you want to use 3 hall sensors? Wouldn't two be enough?
Good idea about measuring the torque. I never thought on using an electronic scale.
The problem with my ideas on measuring the torque was always the turning part of the winder which would turn the sensor and therefore also the cabling.
Wile reading your post, I maybe have a solution for my problem. I have to think about it and will write more as soon as I see that it could work.
I am still looking forward to your solution.
Arduino is a good solution especially if you used it before. I never used them, but the Arduino Uno board has the same processor I am using. Its also an Atmega328p.
Therefore it would be easy to use it in your follow up project without the arduino hardware.
If you like to skip the Arduino step, I could offer you one of my prints. I would also share my code, including the library for the display. It's just an offer, you can decide what's easier for you.
The programming environment is also available for Mac. An apprentice of mine uses it on his privat mac.
Look here for some install instructions http://www.ladyada.net/learn/avr/setup-mac.html
From my side, you dont have to open a new thread. If you want so, it's fine too. Feel free whatever you want