iot-contact/pcb/power.kicad_sch, branch mdnsIoT device to check if doors and windows are closed or openhttps://cgit.xengineering.eu/iot-contact/atom?h=mdns2025-07-29T09:50:59Zpcb: power: Add DC fuse2025-07-29T09:50:59Zxengineeringme@xengineering.eu2025-07-29T09:48:45Zurn:sha1:6b1ef67728ac3d315abbea6abed1c4c60ce28a47
While the AC fuse is more critical it still might be a good idea to not
completely rely on the fuse of the PoE PSE.
pcb: power: Fix missing pull-up on regulator EN2025-07-27T16:16:16Zxengineeringme@xengineering.eu2025-07-27T16:14:39Zurn:sha1:32ae5e2e0c2869f0ac778bb95a33a2219401c68c
The +3.3V regulator has an enable (EN) pin. This was connected to the
power-good (PG) output of the +5V regulator.
It was overlooked that the PG pin is an open-collector pin and thus a
pull-up resistor is required.
This issue was found with the KiCad electrical rules check (ERC).
pcb: power: Add `PWR_FLAG` symbols2025-07-25T20:25:27Zxengineeringme@xengineering.eu2025-07-25T20:02:41Zurn:sha1:d3e7f19f1f87b03e9a7c8a170b9c4351ac565268
This resolves ERC issues. The ERC complains that an power input is not
fed by a power output if there is a component like a ferrite bead or 0
Ohm resistor between the two.
The `PWR_FLAG` tells the ERC that it was explicitly checked that this is
not a mistake.
pcb: Reset part annotations2025-07-25T16:21:10Zxengineeringme@xengineering.eu2025-07-25T16:21:10Zurn:sha1:68d56b6f8e1abeaaa6982245bb73e9f9d712b44cpcb: power: Add 3.3 V regulator2025-07-25T16:07:51Zxengineeringme@xengineering.eu2025-07-25T16:07:51Zurn:sha1:5379ad09d7bdf59d90bf45e0a1e1525f9f06289epcb: Solve external and PoE power supply2025-07-24T20:40:21Zxengineeringme@xengineering.eu2025-07-24T20:40:21Zurn:sha1:19daf5941c95a34eb6596e4a62de541a6080f644
Now there are 6 locations for 3 zero Ohm resistors. Three places to
power by PoE and three to power externally. Never all of them should be
placed.
pcb: power: Add 5V supply based on external input2025-07-24T16:23:50Zxengineeringme@xengineering.eu2025-07-24T16:23:50Zurn:sha1:17cb3a982a40cfb42c15df7ede78919614c300bapcb: ethernet: Add initial schematic2025-07-22T16:18:19Zxengineeringme@xengineering.eu2025-05-25T19:58:15Zurn:sha1:1620d188cfdc9660c69ab50b33d9e69ad99c34eapcb: Update to KiCad 9.x2025-04-01T16:13:10Zxengineeringme@xengineering.eu2025-04-01T16:13:10Zurn:sha1:aa3a6384f14ee7d148b84523aa30723bc1020d39pcb: Add hierarchical labels and connections2025-02-18T18:44:49Zxengineeringme@xengineering.eu2025-02-18T18:44:49Zurn:sha1:968d182429594578654a983d8a5b605f8f152650pcb: Set title to `iot-contact`2025-02-18T18:09:20Zxengineeringme@xengineering.eu2025-02-18T18:09:20Zurn:sha1:ca4bdaf956ac6a100cc386e6119641c35807becapcb: J3: Add non-PoE 5V power input header2025-02-15T21:09:18Zxengineeringme@xengineering.eu2025-02-15T21:02:25Zurn:sha1:60369177e1e9ad171d600d40e8438430e154e558
Power over Ethernet (PoE) has the disadvantage that GND is significantly
below earth. This requires that GND of a PoE-powered device is never
attached to earthed devices.
In production use cases this is no problem. The earth lines are
isolated.
Nevertheless for debugging it is sometimes useful to connect measuring
equipment like logic analyzers and oscilloscopes to the board. This is
not possible with PoE. Thus an alternative earth-based 5V power input is
useful.
pcb: Add sub-schematics2025-02-14T12:41:27Zxengineeringme@xengineering.eu2025-02-03T20:48:04Zurn:sha1:de8bc23e81c136b2153fe93d87e5a5ba9e518878