Creating a Custom Cable: 7-Pin Amphenol Connector and Unique Electrode Input

  • Context: Electrical 
  • Thread starter Thread starter Ephant
  • Start date Start date
  • Tags Tags
    Cable Socket
Click For Summary
SUMMARY

This discussion focuses on constructing a custom cable featuring a 7-pin Amphenol connector and a unique electrode input for biomedical applications. The user seeks information on sourcing the left white electrode input socket and whether it can be purchased or must be custom-made. Recommendations include using twisted wires similar to those in Ethernet cables for the differential red (+) and black (-) inputs, with considerations for wire size based on signal voltage and insulation requirements. The discussion concludes that impedance mismatches at 1 kHz will not significantly affect signal quality due to the short cable length relative to the signal wavelength.

PREREQUISITES
  • Understanding of 7-pin Amphenol connector specifications
  • Knowledge of differential signal wiring techniques
  • Familiarity with twisted pair cable construction
  • Basic principles of impedance and signal integrity
NEXT STEPS
  • Research sourcing options for 1.5mm Touchproof sockets
  • Learn about twisted pair cable shielding techniques
  • Investigate the effects of cable length on signal quality at various frequencies
  • Explore the specifications and applications of differential signaling in biomedical devices
USEFUL FOR

Biomedical engineers, DIY electronics enthusiasts, and anyone involved in custom cable construction for signal transmission in medical applications.

Ephant
Messages
147
Reaction score
2
electrode input cable.jpg


This cable costs $200 so I want to build one. I know where to get the round silver plug at right which is a 7 pin Amphenol and I know the pin designations inside.

I'd like to know if the left white electrode input socket can be found anywhere or it can only be made special at factory. Have you seen anything like it being sold anywhere?

The red (+) and black (-) input is differential with a ground/reference at middle. Should I use twisted wires like used in ethernet cable as the cable? What is the size of wire I should use. How many feet before it can cause enough noises?

I plan to use up to 1000 Hz signal. If the wire and plugs at either end is not matched. Would the impedance mismatched attenuate or cause noises in the signal?

Thanks!
 
Last edited:
Physics news on Phys.org
Ephant said:
Have you seen anything like it being sold anywhere?
What are the physical dimensions of the shell and the electrodes?
Ephant said:
The red (+) and black (-) input is differential with a ground/reference at middle. Should I use twisted wires like used in ethernet cable as the cable?
Twist the (+) and (-) wires, and shield them inside the grounded screen.
Ephant said:
What is the size of wire I should use.
That depends on the unspecified signal amps, the voltage determines the insulation.
The wire should fit in the shell, and terminate sensibly at the electrodes.
Ephant said:
How many feet before it can cause enough noises?
Many. At 1 kHz, a screened twisted pair will be reasonably quiet. How much noise do you need to avoid, and in what environment?
Ephant said:
I plan to use up to 1000 Hz signal. If the wire and plugs at either end is not matched. Would the impedance mismatched attenuate or cause noises in the signal?
The wavelength of a 1 kHz signal would be 3e8/1e3 = 3e5 = 300 km. The cable is very much shorter than that, so there should be no problems at 1 kHz.
Only the total lump capacitance of the cable would be important.
 
It's 1.5mm Touchproof sockets. Voltage is biopotentials of human skin surface. So I can just use ethernet cable?
 
Why do you suppose it costs $200? What-all does it do? What does it plug into?
 
Thread is closed for Moderation...
 
Because this appears to be related to the OP's DIY Biomedical experimentation, the thread will remain closed.
 

Similar threads

  • · Replies 25 ·
Replies
25
Views
2K
Replies
37
Views
6K
  • · Replies 5 ·
Replies
5
Views
4K
Replies
13
Views
4K
  • · Replies 1 ·
Replies
1
Views
2K
Replies
7
Views
4K
Replies
2
Views
3K
  • · Replies 2 ·
Replies
2
Views
8K
  • · Replies 1 ·
Replies
1
Views
10K