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Correction to previous log
08/21/2017 at 05:41 • 0 commentsI was notified that the link I put in the previous project log is broken, it's supposed to be:
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Revision 1 finally done (and for sale)
08/07/2017 at 12:13 • 0 commentsRevision time! A little while ago I uploaded a video where I worked on the revision 1 schematic and layout, and after quite a long wait for the displays as well as about 2 weeks of on-and-off coding on the firmware, it's finally finished.
As it turns out, the MOSFET and resistor approach I used to calibrate the input offset of the current shunt amplifier was not really ideal. The resistor I used to short out the amplifier was actually introducing an additional (significant) error, so I've done a bunch of testing to find out how to salvage this anyway. I ended up having to change out the resistor and MOSFET to both be lower-resistance, which fortunately got them completely in-spec.Also, shipping times from China are very variable. Whereas my first couple of OLED displays were here within a week, this shipment took a month. I hate sourcing from China for this reason, it's so hard to plan products.
Anyway, here's a little update video and if you like the project, check out the schematic and documentation on https://muxtronics.nl/usbcsensor.html