Hi, first, your project is very cool. I don't really figured out where you are in the advancements. Actually only shoulders move, that's rights ?

nice work . as5600 is a pain to use in i2c mode so a as5048 is much better and can be daisy changed in spi mode. u can always get 5 samples from the ams website to do your testing. 

I read about that limitation and plan to put 6 sensors on a I2C multiplexer. I've Never used either so there will be a learning curve.

I'm aware of the as5048's but the A variant is ~20$ while the I2C B variant doesn't appear to be easily sourced. The AS5600s have the I2C limitation but I bought them for ~3$ each plus 3-4$ for each multiplexer.

I will have to look into getting the dev samples. 5 is not enough for my project but any components are nice to have on the shelf.

u might be able to get away with running as5600 in analog mode as their signal is quite clean over shorter distances. So all u need is free analog pins on the mcu/  

Indeed you can use the OUT pin just as you would use an analog potentiometer but be aware that there is a deadband on these sensors so it’s going to lose a step (or more) if you attempt to use this past 360 degree rotations. I too bought a lot of these to use in my quadruped but I was disappointed to not only find out this limitation, but also that the maths involved for using it behind a gearbox made it unreasonable. I have since ordered the AS5048A for testing but for now I’m living with hall encoder based solutions until I make a decision. I think I paid about $2 a unit for the 5600’s so sunk cost is okay with me. It’s a shame because they otherwise are fantastic absolute encoders! 

I'm not sure why I can't reply to your later comment or to Grayson?? Thread reply level limit?

To both of you; I had originally planned for 3 actuators per STM32, then 4 STM32s which would have been one for each leg. The encoders had two channels and the AS5600 analog signal would have been a slight reduction in IO but the appeal of I2C removing all 6 lines opened up putting 6 actuators on one STM32 and breaking front/back sets.

Keep in mind these sensors are measuring joint angles often less than 90° with magnets set at arbitrary locations. I want to avoid burning min/max to these sensor to avoid their 3 burn limit and keep them open for future project. I2C method allows setting temporary (volatile memory) limit's and ranges on startup through registers so simply; multiplex each sensor, read their as installed range from the actuator min/max limits, record those ranges, then set them for each sensor on startup. everything boots up calibrated and with accurate position.

Understanding the AS5600 I2C address limitation pushed me to pick up a few TCA9548A multiplexers to maintain setting non-burned set points. 12 AS5600 and two TCA9548A is a fraction of the cost of 12 AS5048Bs and I don't need the 12 to 14bit resolution jump. Just not worth the cost when I can make the AS5600s work just as well. Looking back at my order, I bought 20 from aliexpress for 1.77$ and paid 18$ for half the shipping time. 20 units cost me the same as two of the alternate.

Thanks for the reply's and keep them coming. I'm learning this as I go and there is more to learn!

WIP, will update as progress continues.