Chat

Welcome to Flux

Treat Flux like your intern. Tell it what you'd like to build and it'll get to work. You can also ask it questions, brainstorm ideas, and teach it your preferences. Learn More

Explain project

Write a project description

Find schematic issues

Create a test plan

Simulate a circuit

Prepare for Manufacturing

Component Selection Workflow

New Subsystem Wizard

Write I2C initialization code

Generate firmware skeleton

For Shielded RJ45 connector, is it better to connect SH-1 and SH-2 to ground or ...

suckatpcbb

@copilot Is it ok for me to assume that pin1 and pin2 are the same twisted pair, Pin3 and Pin4 are the same twisted pair, etc?

copilot

It's generally a reasonable assumption that pairs of adjacent pins on RJ-45 connectors correspond to the same twisted pair, particularly when following standard Ethernet wiring schemes such as T568A or T568B. The typically used pinout for Ethernet cables, which would use an RJ-45 connector like the RJHSE-5380, is as follows:

Pair 1: Pins 1 and 2
Pair 2: Pins 3 and 6
Pair 3: Pins 4 and 5
Pair 4: Pins 7 and 8

Based on this standard pinout, your assumption would not always hold true as per the T568A and T568B standards, because the pairs are not simply adjacent pins except for the first pair (Pins 1 and 2). Here's the standard mapping for clarity:

T568A

Pair 1: Pins 4 and 5 (Blue)
Pair 2: Pins 3 and 6 (Green)
Pair 3: Pins 1 and 2 (Orange)
Pair 4: Pins 7 and 8 (Brown)

T568B

Pair 1: Pins 4 and 5 (Blue)
Pair 2: Pins 1 and 2 (Orange)
Pair 3: Pins 3 and 6 (Green)
Pair 4: Pins 7 and 8 (Brown)

If you're following standard wiring, you'll need to check the specific Ethernet wiring scheme you intend to use.

For your project, the assignments for the pins on your RJHSE-5380 are as follows:

J5:1 and J5:2: First twisted pair (usually TX+ and TX-).
J5:3 and J5:5: Second twisted pair (usually RX+ and RX-).
J5:4 and J5:5
J5:7 and J5:8

In summary, Pins 1 and 2 form a pair; Pins 3 and 6 form a pair; Pins 4 and 5 form a pair, and Pins 7 and 8 form a pair.

Always refer to your specific component's datasheet or wiring standard for the most accurate information.

suckatpcbb

@copilot For Shielded RJ45 connector, is it better to connect SH-1 and SH-2 to ground or just one of them is enough?

copilot

For a shielded RJ45 connector like the RJHSE-5380, it is generally recommended to connect the shield pins (SH-1 and SH-2) to ground. The purpose of the shield is to protect against electromagnetic interference (EMI) and ensure proper grounding improves the effectiveness of the shielding. Here’s a breakdown of the connections:

Connect both SH-1 and SH-2 to ground: This ensures that the shield is adequately grounded and provides better EMI protection. Grounding both shield pins helps to minimize any potential voltage differences that could cause interference.

To summarize, you should:

Connect $J5:Shield \, (Pin \, 1)$ and $J5:Shield \, (Pin \, 2)$ to GND.

Would you like to make these connections in your design?

I know that i2c is not meant to be used on long distance application. However, i...

suckatpcbb

@copilot what's the resistance of the i2c pull-up resistor on arduino mega?

copilot

The Arduino Mega 2560 typically uses two 10 kΩ pull-up resistors for the I2C lines (SDA and SCL). These resistors are connected to the 5V supply rail. If you need to adjust these values for specific applications or increased bus speed, you might consider different resistor values.

Would you like any further assistance with the Arduino Loadcell System Shield project?

suckatpcbb

@copilot I know that i2c is not meant to be used on long distance application. However, if I have to do it, is it better to put the scl and sda lines on the same rj45 twisted pair to reduce noise? of is it better to put them on separate twisted pair?

copilot

Using I2C over long distances can indeed be challenging due to its susceptibility to noise and signal degradation. However, here are some considerations to optimize performance:

Twisted Pair Configuration

Placing SCL and SDA on the Same Twisted Pair:
- Advantages:
  - Twisting the two signal lines together can help to cancel out some external electromagnetic interference due to the close proximity of the conductors.
- Disadvantages:
  - This configuration can potentially cause crosstalk between the SCL and SDA lines, which could degrade signal integrity and data reliability.
Placing SCL and SDA on Separate Twisted Pairs:
- Advantages:
  - Reduces the chance of crosstalk between the clock and data lines.
- Disadvantages:
  - Each pair will have a different level of interference cancellation, which might make one signal cleaner than the other, depending on the pairing and environmental noise.

Recommended Approach

Twisted Pair Configuration: Pair each signal line (SCL and SDA) with a ground line. This reduces crosstalk and improves signal integrity.
- Pair 1: SCL + GND
- Pair 2: SDA + GND

Practical Tips

Pull-Up Resistors:
- Use strong pull-up resistors on the SCL and SDA lines. Values around 1kΩ to 4.7kΩ are typical for shorter distances, but you may need to experiment with lower values (e.g., 330Ω) for longer distances to maintain signal integrity.
Shielding:
- Using shielded cable for the RJ45 can provide an additional layer of noise protection. Ensure the shield is grounded properly.
I2C Extenders:
- You can use I2C bus extenders or buffers that are specifically designed to extend the I2C communication distance and improve noise immunity. Components like the P82B96 can be very effective for this purpose.
Reduced Speed:
- Reduce the I2C bus speed. The standard 100 kHz or 400 kHz speeds may be too fast for long distances. Experiment with the slowest possible speed that meets your application requirements.

By pairing each signal with a ground, you can improve the noise immunity of your system while reducing crosstalk, which is a common issue when transmitting high-frequency signals over longer distances.

Load_Cell_4_DRDY

Load_Cell_4_SCL

Load_Cell_4_DRDY

RESET

Load_Cell_4_SDA

Load_Cell_5_DRDY

Load_Cell_2_DRDY

Load_Cell_5_SCL

Load_Cell_3_DRDY

Load_Cell_5_SDA

Load_Cell_3_DRDY

Load_Cell_6_DRDY

Load_Cell_5_DRDY

Load_Cell_3_SCL

Load_Cell_1_DRDY

Load_Cell_3_SDA

Load_Cell_6_DRDY

+5V

VIN

+5V

+3V3

+5V

J13

J12

Capacitance

10uF

Resistance

Capacitance

10uF

Resistance

Capacitance

10uF

Capacitance

10uF

Reviews

Ground
A common return path for electric current. Commonly known as ground.
jharwinbarrozo
20.5M
Net Portal
Wirelessly connects nets on schematic. Used to organize schematics and separate functional blocks. To wirelessly connect net portals, give them same designator. #portal
jharwinbarrozo
43.0M
Power Net Portal
Wirelessly connects power nets on schematic. Identical to the net portal, but with a power symbol. Used to organize schematics and separate functional blocks. To wirelessly connect power net portals, give them the same designator. #portal #power
jharwinbarrozo
11.4M
Generic Resistor
A generic fixed resistor ideal for rapid circuit topology development. Its footprint automatically adapts based on the selected package case code—supporting 0402, 0603, 0805, 1203, and many other standard SMD packages, as well as axial horizontal and vertical configurations. Save precious design time by seamlessly add more information to this part (value, footprint, etc.) as it becomes available. Standard resistor values: 1.0 ohm, 10 ohm, 100 ohm, 1.0k ohm, 10k ohm, 100k ohm, 1.0M ohm 1.1 ohm, 11 ohm, 110 ohm, 1.1k ohm, 11k ohm, 110k ohm, 1.1M ohm 1.2 ohm, 12 ohm, 120 ohm, 1.2k ohm, 12k ohm, 120k ohm, 1.2M ohm 1.3 ohm, 13 ohm, 130 ohm, 1.3k ohm, 13k ohm, 130k ohm, 1.3M ohm 1.5 ohm, 15 ohm, 150 ohm, 1.5k ohm, 15k ohm, 150k ohm, 1.5M ohm 1.6 ohm, 16 ohm, 160 ohm, 1.6k ohm, 16k ohm, 160k ohm, 1.6M ohm 1.8 ohm, 18 ohm, 180 ohm, 1.8K ohm, 18k ohm, 180k ohm, 1.8M ohm 2.0 ohm, 20 ohm, 200 ohm, 2.0k ohm, 20k ohm, 200k ohm, 2.0M ohm 2.2 ohm, 22 ohm, 220 ohm, 2.2k ohm, 22k ohm, 220k ohm, 2.2M ohm 2.4 ohm, 24 ohm, 240 ohm, 2.4k ohm, 24k ohm, 240k ohm, 2.4M ohm 2.7 ohm, 27 ohm, 270 ohm, 2.7k ohm, 27k ohm, 270k ohm, 2.7M ohm 3.0 ohm, 30 ohm, 300 ohm, 3.0K ohm, 30K ohm, 300K ohm, 3.0M ohm 3.3 ohm, 33 ohm, 330 ohm, 3.3k ohm, 33k ohm, 330k ohm, 3.3M ohm 3.6 ohm, 36 ohm, 360 ohm, 3.6k ohm, 36k ohm, 360k ohm, 3.6M ohm 3.9 ohm, 39 ohm, 390 ohm, 3.9k ohm, 39k ohm, 390k ohm, 3.9M ohm 4.3 ohm, 43 ohm, 430 ohm, 4.3k ohm, 43K ohm, 430K ohm, 4.3M ohm 4.7 ohm, 47 ohm, 470 ohm, 4.7k ohm, 47k ohm, 470k ohm, 4.7M ohm 5.1 ohm, 51 ohm, 510 ohm, 5.1k ohm, 51k ohm, 510k ohm, 5.1M ohm 5.6 ohm, 56 ohm, 560 ohm, 5.6k ohm, 56k ohm, 560k ohm, 5.6M ohm 6.2 ohm, 62 ohm, 620 ohm, 6.2k ohm, 62K ohm, 620K ohm, 6.2M ohm 6.8 ohm, 68 ohm, 680 ohm, 6.8k ohm, 68k ohm, 680k ohm, 6.8M ohm 7.5 ohm, 75 ohm, 750 ohm, 7.5k ohm, 75k ohm, 750k ohm, 7.5M ohm 8.2 ohm, 82 ohm, 820 ohm, 8.2k ohm, 82k ohm, 820k ohm, 8.2M ohm 9.1 ohm, 91 ohm, 910 ohm, 9.1k ohm, 91k ohm, 910k ohm, 9.1M ohm #generics #CommonPartsLibrary
jharwinbarrozo
1.5M
Generic Capacitor
A generic fixed capacitor ideal for rapid circuit topology development. You can choose between polarized and non-polarized types, its symbol and the footprint will automatically adapt based on your selection. Supported options include standard SMD sizes for ceramic capacitors (e.g., 0402, 0603, 0805), SMD sizes for aluminum electrolytic capacitors, and through-hole footprints for polarized capacitors. Save precious design time by seamlessly add more information to this part (value, footprint, etc.) as it becomes available. Standard capacitor values: 1.0pF, 10pF, 100pF, 1000pF, 0.01uF, 0.1uF, 1.0uF, 10uF, 100uF, 1000uF, 10000uF 1.1pF, 11pF, 110pF, 1100pF 1.2pF, 12pF, 120pF, 1200pF 1.3pF, 13pF, 130pF, 1300pF 1.5pF, 15pF, 150pF, 1500pF, 0.015uF, 0.15uF, 1.5uF, 15uF, 150uF, 1500uF 1.6pF, 16pF, 160pF, 1600pF 1.8pF, 18pF, 180pF, 1800pF 2.0pF, 20pF, 200pF, 2000pF 2.2pF, 22pF, 220pF, 2200pF, 0.022uF, 0.22uF, 2.2uF, 22uF, 220uF, 2200uF 2.4pF, 24pF, 240pF, 2400pF 2.7pF, 27pF, 270pF, 2700pF 3.0pF, 30pF, 300pF, 3000pF 3.3pF, 33pF, 330pF, 3300pF, 0.033uF, 0.33uF, 3.3uF, 33uF, 330uF, 3300uF 3.6pF, 36pF, 360pF, 3600pF 3.9pF, 39pF, 390pF, 3900pF 4.3pF, 43pF, 430pF, 4300pF 4.7pF, 47pF, 470pF, 4700pF, 0.047uF, 0.47uF, 4.7uF, 47uF, 470uF, 4700uF 5.1pF, 51pF, 510pF, 5100pF 5.6pF, 56pF, 560pF, 5600pF 6.2pF, 62pF, 620pF, 6200pF 6.8pF, 68pF, 680pF, 6800pF, 0.068uF, 0.68uF, 6.8uF, 68uF, 680uF, 6800uF 7.5pF, 75pF, 750pF, 7500pF 8.2pF, 82pF, 820pF, 8200pF 9.1pF, 91pF, 910pF, 9100pF #generics #CommonPartsLibrary
jharwinbarrozo
1.5M
Generic Inductor
A generic fixed inductor suitable for rapid circuit topology development. The footprint automatically adapts based on the selected package, supporting standard SMD sizes (e.g., 0402, 0603, 0805) as well as well-known inductor packages such as SDR1806, PA4320, SRN6028, and SRR1260. Standard inductor values: 1.0 nH, 10 nH, 100 nH, 1.0 µH, 10 µH, 100 µH, 1.0 mH 1.2 nH, 12 nH, 120 nH, 1.2 µH, 12 µH, 120 µH, 1.2 mH 1.5 nH, 15 nH, 150 nH, 1.5 µH, 15 µH, 150 µH, 1.5 mH 1.8 nH, 18 nH, 180 nH, 1.8 µH, 18 µH, 180 µH, 1.8 mH 2.2 nH, 22 nH, 220 nH, 2.2 µH, 22 µH, 220 µH, 2.2 mH 2.7 nH, 27 nH, 270 nH, 2.7 µH, 27 µH, 270 µH, 2.7 mH 3.3 nH, 33 nH, 330 nH, 3.3 µH, 33 µH, 330 µH, 3.3 mH 3.9 nH, 39 nH, 390 nH, 3.9 µH, 39 µH, 390 µH, 3.9 mH 4.7 nH, 47 nH, 470 nH, 4.7 µH, 47 µH, 470 µH, 4.7 mH 5.6 nH, 56 nH, 560 nH, 5.6 µH, 56 µH, 560 µH, 5.6 mH 6.8 nH, 68 nH, 680 nH, 6.8 µH, 68 µH, 680 µH, 6.8 mH 8.2 nH, 82 nH, 820 nH, 8.2 µH, 82 µH, 820 µH, 8.2 mH #generics #CommonPartsLibrary
jharwinbarrozo
15.8k
Terminal
An electrical connector acting as reusable interface to a conductor and creating a point where external circuits can be connected.
natarius
RMCF0805JT47K0
47 kOhms ±5% 0.125W, 1/8W Chip Resistor 0805 (2012 Metric) Automotive AEC-Q200 Thick Film #forLedBlink
jharwinbarrozo
1.2M
875105359001
10uF Capacitor Aluminum Polymer 20% 16V SMD 5x5.3mm #forLedBlink #commonpartslibrary #capacitor #aluminumpolymer #radialcan
jharwinbarrozo
1.2M
CTL1206FYW1T
Yellow 595nm LED Indication - Discrete 1.7V 1206 (3216 Metric) #forLedBlink
jharwinbarrozo
1.1M

Project Name

Arduino Force Units Connection Shield

Description

An I2C extension shield with 6 shielded ethernet ports and a TCA9548 breakout board.

This board is for the target side, any microcontroller with a standard Arduino header can use it. With proper target side hardware and an SSTP ethernet cable, the board provides robust i2c communication over 10ft(could be longer, haven't tested it yet) with a bitrate of 400kHz under a noisy environment( near motors, power cables, switches, etc).

The shield board provides power to the target side and can power the i2c device. The board also supports drdy trigger, which is available on many i2c sensors. The TCA9548 breakout board is for a scenario in which all of your i2c devices have the same address.

#Arduino #Uno #Shield #Template #project-template #project

Properties

Properties describe core aspects of the project.

Pricing & Availability

Distributor	Qty 1
LCSC	$2.95

Controls

Welcome 👋

Flux helps you build PCBs faster with an AI teammate!

Create your account to collaborate, stay updated, fork your own version, and get instant answers from our AI agent.

suckatpcbb / Arduino Force Units Connection Shield

Schematic