After a significant amount of work I’m close to being able to show V3 working on a bike. However there are ramifications to my intention to post the code / schematics / pcb. The problem is that the pcb is continually showing faults in the design that should be addressed.
1) I forgot a trace to the AP2, so it’s manually grounded
2) I have a broken trace when I had to fix some traces to get the board made. I forgot to connect this one and it has had to be hacked.
3) the precision voltage reference was the worse idea I’ve had for this entire project. In fact I’m going to hack my own PCB to install two Vishay through hole resistors to sort this horrid deficiency out.
4) Shear gauges on the right arm are not nearly as accurate as double bending arrangement. This should be something of note for anyone interested in StageOne. It hasn’t been talked about but if they are using a surface shear gauge you could be introducing some inaccuracy. It works, but the double bending arrangement IS more accurate. This is a thumbs up to Rotor who are using a double bending arrangement inside their crank.
5) Linear voltage regulator sucks power. It’s a waste and requires 2 x CR2032 to power the meter with higher drain. Not good. Connecting the 3V coin cell directly with a voltage divider reference is smarter.
6)Size: This is all too large and ridiculous in size.
7) Coin holder: It’s terrible
8) Reset / On-Off Switch: Need them
9) ADC / Amp / Gauge should be powered by an output pin so they can be turned off.
10) nRF51422. This is such an appealing device. The size of an AP2 chip but with a 32bit ARM core. Dual SPI, built in ANT+. But I have 0 true experience with ARM Cortex-M0. So little that I don’t even know the equivalent of an ISP and how to even wire the chip to be programmed after assembly.
I’m working on buying a site for the commercial side of this project. So I’m not releasing the name however here is a teaser. A-X-X-X-X-X-X. Maybe I’ll release one letter per post!