Farfadet

I finally took some time to solder the magnetic encoder and XLR PCBs.

Here they are :

The encoder boards has a AMS AS5132 chip, which should be capable of a 1° resolution.

It has a NEMA23 form factor and can double as a mounting support for the TMC5130 board.

I haven't had the time to test it with the TMC5130 but the encoder IC seems to work :

The yellow LED is connected to the PWM output of the encoder IC, that encodes the angular position into the duty cycle. On each turn of the motor a ramp followed by a step is clearly visible, which means that the encoder works !

I will still have to experiment with the precision, but I think that the magnet placement is not ideal : too far away from the chip (the datasheet suggests a 1~2mm distance, here it is at least at 4mm) and stuck directly on the shaft which weakens further the magnetic field.

Some of the connections didn't reflow well... (look at the bottom of the image). Maybe because the board was on standoffs to preserve the bottom side components ? I've never had this happen before.

Following steps :

• hot-air rework
• de-panelization (a bit harsh on the PCBs, I will have to rework the panel connections for the future revisions)
• through hole soldering
• heat sink fixed with thermal adhesive

And....

As expected, v1.1 boards have better thermal performances (they are 4-layer instead of 2-layer). Heat spreads into the whole PCB including the mounting holes and I was able to pull a bit more current without the TMC5130 overtemp protection kicking in.

However these new boards still can't use the max 1.68A / phase current in this configuration. I will have to test with some fans that I have laying around if the full current can be achieved.

Anyway with the recent announcement of the TMC5160 by Trinamic a higher current Farfadet with external power stage will probably join the party :)

Next steps : soldering and trying the magnetic encoder and XLR extension boards... And a lot of software and documentation work !

Fresh PCBs and stencil from the factory !

We have here :

• a new version of Farfadet main board (stepper motor driver), hopefully with better thermal performances than the previous
• an extension board with XLR connectors
• an extension board with a magnetic encoder for feedback
• a transceiver board designed to fit on a Teensy, with XLR or picoBlade connectivity to the Farfadets

Testing the magnetic encoder PCB fit on NEMA17 & NEMA23 :

First time ordering with ALLPCB : the quality looks excellent and that was definitely the fastest PCB order I've ever seen (less than 1 week, shipping included, for an order with 2-layer / 4-layer boards and a stencil).