USB-C Temperature and Humidity Sensor Node

0:46

Clarifying connections.

Yes — here is the cleaner connection list, written as actual signal paths.
And you’re right to call out R1: right now it has no connection in the current design state. Per the project-explanation rule, I should describe what is actually connected, and separately flag gaps like unconnected parts
Important note about R1
  • R1 is currently floating / unused
  • It does not belong to any active net in the current schematic
  • So if you do not see it participating in the circuit, that is because it is not actually wired right now
Main signal path
This is the pulse path as it currently exists:
Pulse input path
That matches the recommended style of explaining a design by explicit signal flow from input to output
Protection and bias on the pulse input
The pulse input node is this point:
Input node
So the cleaner branch view is:
and from that same node:
  • R3:P2
    -> R2:P2
    -> R2:P1
    -> GND
and also:
  • R3:P2
    -> D1:K
    -> D1:A
    -> GND
Power path
5 V input
3.3 V regulator output
Ground path
These are on ground:
Also tied to ground are the unused gates on U1:
Very short build-style summary
If you want the simplest readable version:
Signal Clamp and pull-down at input node Power
  • J2:1 -> U2:VI
  • U2:VO -> U1:VCC
  • J2:2 -> GND
  • U1:GND -> GND
  • U2:GND -> GND
Capacitors
  • C1:P1 -> 5V_IN, C1:P2 -> GND
  • C2:P1 -> 5V_IN, C2:P2 -> GND
  • C3:P1 -> 3V3, C3:P2 -> GND
  • C4:P1 -> 3V3, C4:P2 -> GND
Unused
  • R1 -> not connected
  • J2:4 -> AUX only
One concern
There is a likely issue with the current state: the unused sections of U1 have both inputs and outputs tied to GND. That is what the project currently shows, but I would want to review that before treating the design as final, because documenting actual state and separately flagging concerns is the correct way to present it
If you want, I can next give you:
  • a pin-by-pin wiring checklist for your student, or
  • a corrected recommended connection list that cleans up R1 and the unused U1 gates.
Clean net list
Trace R1 connections
Check unconnected pins
Use pin-to-pin format
7 days

Refine this doc
Ask about this doc
Design Notes
PDT20A BeagleBone THT Pulse Interface
Final architecture
  • Input connector: J1 through-hole BNC
  • Input protection: D1 = 1N4148 through-hole diode
  • Input damping: R3 = 33 ohm axial resistor
  • Pulse conditioning: U1 = SN74HC14N PDIP-14, powered from 3.3 V
  • Output connector: J2 through-hole 1x4 2.54 mm header
  • Local regulation: U2 = MCP1700-3302E/TO with C1, C2 on input and C3, C4 on output/logic supply
Signal flow
  • J1 pulse input -> R3 -> U1 gate 1 input
  • D1 clamps the pulse input node to ground for negative excursion protection
  • U1 gate 1 output feeds U1 gate 2 input
  • U1 gate 2 output drives the BeagleBone pulse output on J2 pin 3
Power flow
  • J2 pin 1 provides 5 V input
  • U2 regulates 5 V to 3.3 V
  • C1 = 10 uF bulk input capacitor
  • C2 = 100 nF input bypass capacitor
  • C3 = 1 uF regulator output capacitor
  • C4 = 100 nF logic decoupling capacitor for U1
Layout intent
  • Board size: 70 mm x 70 mm
  • Stackup: Standard 2 Layer
  • Pulse path kept on top layer and as short/direct as possible
  • Power conditioning grouped near the BeagleBone-side connector
  • Through-hole parts spaced generously for hand soldering
Current implementation note
  • Unused 74HC14 gates are tied to ground so the DIP package remains well-defined in a hand-built board.

    PDT20A BeagleBone THT Pulse Interface

    Final architecture

    Signal flow

    Power flow

    Layout intent

    Current implementation note

Documents

    Design Notes

Assets

Assets are files uploaded to this project which can be used in various ways.

PDT20A BeagleBone THT Pulse Interface thumbnail
High-speed pulse interface board that conditions a 5 V, 50-500 ns PDT20A-HN pulse for safe 3.3 V detection by a BeagleBone Black while preserving timing integrity.

Properties

Properties describe core aspects of the project.

Pricing & Availability

Distributor

Qty 1

Arrow

$3.87–$6.69

Digi-Key

$7.85

LCSC

$10.30

Mouser

$7.54

TME

$8.96

Verical

$3.45–$8.53

Controls