#  Step 3: Sensor Setup 

 



 ##  

  expand\_more  

 
  

 

Before hooking up the sensor to the equipment, we need to first fill the sensor with conductive fluid. In this guide, we use 5 %wt saline solution, which is simply 5 parts salt to 95 parts water by weight.

Sort ![setup-step1](/sites/g/files/omnuum4601/files/2024-11/setup-step1.jpg)

 



Weigh **10 grams** of **salt** in a container

 ![setup-step2](/sites/g/files/omnuum4601/files/2024-11/setup-step2.jpg)

 



Add **190 grams** of **water** to total of **200 grams** of solution.

*Filling the sensor only requires about 5 ml of saline. The solution is prepared in bulk due to the ease of weighing.*



 ![setup-step3](/sites/g/files/omnuum4601/files/2024-11/setup-step3.jpg)

 



Add **3 drops** of **food coloring**.

Coloring the saline is important for checking for air bubbles within the sensor.



 ![setup-step4](/sites/g/files/omnuum4601/files/2024-11/setup-step4.jpg)

 



Stir well until the solution is homogeneously colored.

 ![setup-step5](/sites/g/files/omnuum4601/files/2024-11/setup-step5.jpg)

 



Using a syringe, pull about **9 ml** of the solution.

There will be some air bubbles along with dissolved gasses within syringe. **Follow the instructions in** [**this video**](https://youtu.be/3r9HPWd5wKk?t=45s) **to vacuum degas the bubbles.** Of course, vacuum degassing the whole container is also fine.



 ![setup-step6](/sites/g/files/omnuum4601/files/2024-11/setup-step6.jpg)

 



Once degassed, the solution is ready to be injected into the sensor.

 ![setup-step7](/sites/g/files/omnuum4601/files/2024-11/setup-step7.jpg)

 



Hold the sensor up at the ends of the silicone tubes in to a "U" shape like shown. Doing so will prevent air bubbles from being trapped while filling the sensor.

 ![setup-step8](/sites/g/files/omnuum4601/files/2024-11/setup-step8_0.jpg)

 



Slide the syringe tip into the short end of the sensor.

 ![setup-step9](/sites/g/files/omnuum4601/files/2024-11/setup-step9.jpg)

 



Slowly fill the sensor by depressing the syringe plunger in short strokes while staying vertical.

 ![setup-step10](/sites/g/files/omnuum4601/files/2024-11/setup-step10.jpg)

 



Make sure there are no air bubbles between the two conductive ends within the sensor body. Refill if necessary.

 ![setup-step11](/sites/g/files/omnuum4601/files/2024-11/setup-step11.jpg)

 



Plug a stopper in one end of the sensor, remove the syringe and plug in another stopper at the other end.

 ![setup-step13](/sites/g/files/omnuum4601/files/2024-11/setup-step13.jpg)

 



Remove the plug from the longer silicone tube and plug the tube into the pressure sensor.

*Squeezing the end while inserting the tube will ensure that air is not trapped between the pressure sensor and the fluid.*

*The images here are for illustrative purposes only. Please wire up your hardware accordingly.*



 ![setup-step14](/sites/g/files/omnuum4601/files/2024-11/setup-step14.jpg)

 



Plug in leads from the voltage divider circuit or data acquisition hardware.

*The images here are for illustrative purposes only. Please wire up your hardware accordingly.*



 ![setup-step15](/sites/g/files/omnuum4601/files/2024-11/setup-step15_0.jpg)

 



**The sensor is now complete and ready to be used!**





### Bibliography

Preechayasomboon et. al. [Multi-Modal Sensing and Actuation in Biomechanical Hydraulic and Pneumatic Systems.](/publications/multi-modal-sensing-and-actuation-biomechanical-hydraulic-and-pneumatic?admin_panel=1)

[Export Citation](/bibcite/export?content_filter%5B0%5D=1333742&format=bibtex)

### Contributors

Pornthep Preechayasomboon

Gaurav Mukherjee

Eric Rombokas