Hello everyone,
I am reaching out to the Arduino community for guidance and advice on a project I am working on. My training is in neurobiology and medicine, so I am facing some challenges in the engineering aspect of the project. I would greatly appreciate your help!
The goal of this somatosensory project is to deliver air puff stimuli of varying frequency and pressure to human participants, specifically targeting 6 locations on their legs and arms. So far, we have successfully controlled 6 normally closed solenoid valves using an Arduino. However, we are now struggling with the next part of the system, which involves a pancake air compressor that supplies air to an electropneumatic pressure regulator (ITV1050-21N2S4) from SMC Pneumatics. This pressure regulator is responsible for applying air puffs at varying pressures. Precision and automaticity is key, especially for calibrating the air puffs’ pressure at each of the 6 sites. The airflow goes from the air compressor to the pressure regulator, then to a manifold, and finally to the solenoid valves. Also, since we already have 6 solenoids being controlled by the first Arduino, we are utilizing a second Arduino solely for the pressure regulator.
Here are some specific details about the ITV1050-21N2S4 pressure regulator (https://www.smcpneumatics.com/ITV1050-21N2S4.html):
- Power voltage: 24VDC
- Input signal range: 0~5VDC. This allows us to adjust the pressure based on the electrical signal we provide. At 0VDC, the regulator is set at 0.005MPa, and at 5VDC, it is set at 0.9MPa.
- Monitor output: analog (1~5VDC)
The SMC straight cord that came with the ITV has the following wires: white (input signal), blue (common/ground), brown (positive power), and black (monitor output signal). To power and control the ITV, I have a 24VDC power brick and a PWM module. I chose the PWM module because the ITV requires a constant input voltage, which needs to be converted into a variable input voltage for control. This is the plan I have developed:
- Connect the SMC Blue and SMC Brown wires to the negative and positive outputs of the power supply, respectively.
- Connect the SMC White wire to the output of the smoothing module, with the PWM pin going to the input of the smoothing module (pending).
- The SMC Black wire could potentially be fed back into the Arduino for monitoring purposes (pending).
For the power supply to the brick, I connected the power cord's hot wire to AC(L), the neutral wire to AC(N), and the green ground wire to FG(G). Since the 12V DC output from the power brick serves as the power input to the pressure regulator, I wired the following portions of the SMC pneumatics control cord:
- V: SMC Blue wire (SMC pneumatics control cord)
- +V: SMC Brown wire (SMC pneumatics control cord)
At this point, I am unsure about the next steps regarding the SMC white and black wires, as mentioned in my plan above. As I do not have an engineering background, I am uncertain if this wiring setup will work effectively. I am also unsure whether I should use the PWM module alone or combine it with a MOSFET. Additionally, I am considering whether I should attempt voltage step-down or explore other approaches that allow simultaneous modulation of power and control by the Arduino. Figuring out the answers to these questions has been particularly difficult as I have been unable to find similar setups online for this particular pressure regulator.
Any guidance or suggestions from the community would be greatly appreciated. Thank you in advance for your help!
