Medical physiotherapy ventilator controller

Single chip microcomputer STM32L151CCU6

RF cable can be customized for other specifications

Mobile phone crystal 3.2*2.5mm 3225 26M (26.000MHZ) 7.5PF 10PPM 20PPM 30PPM

The physiotherapy ventilator used clinically in small and medium-sized hospitals continuously supplies air to the patient's nasal cavity. This is inconsistent with the respiratory law that should stop the nasal air supply during breathing, and the patient may feel uncomfortable. The medical physiotherapy ventilator controller introduced in this example can control the physiotherapy ventilator to automatically start the motor operation when the patient inhales, and automatically cut off the working power of the motor during exhalation, which is energy-saving and practical.
Circuit Operation Principle The medical physiotherapy ventilator controller circuit consists of an unsteady oscillator, a control circuit, and a power supply circuit, as shown in Figure 9-155.

The non-stable oscillator circuit is composed of resistors R1, R2, a potentiometer RP, capacitors C1, C2, and a time base integrated circuit ICl.
The control circuit consists of resistors R3-R5, transistors V1, V2, diode VD and relay K.
The power circuit is composed of a power transformer T, a rectifier bridge stack UR rectifier, a filter capacitor C3, C4, and a three-terminal voltage regulator integrated circuit IC2.
Turn on the power, AC 220V voltage after T step-down, UR rectification, C3 filtering and IC2 voltage regulation, provide +9V working power for the non-stable oscillator and control circuit.
After the non-stable oscillator is energized, its 3-pin output frequency is 25-40Hz oscillation pulse signal, so that Vl and V2 are intermittently turned on, and K and M are working. When the 3 pin of ICl outputs a high level, Vl and V2 are saturated, K is energized, its normally open contact is turned on, and the motor M of the physiotherapy ventilator is energized; when the low level of IC1 is output, Vl And V2 cutoff, K release, M power off and stop working.
Adjusting the resistance of the RP can change the oscillation frequency of the non-steady oscillator, thus changing the operating frequency of the ventilator (when used, it can be adjusted according to the needs of the patient).
Component selection
Rl-R5 uses 1/4W metal film resistor or carbon film resistor.
RP uses a synthetic carbon film linear potentiometer.
Both Cl and C4 use aluminum electrolytic capacitors with a withstand voltage of 16V; C2 uses monolithic capacitors; C3 uses aluminum electrolytic capacitors with a withstand voltage of 25V.
VD selects 1N4007 silicon rectifier diode for use.
UR selects the rectifier bridge stack of lA and 5OV.
Vl selects S9013 type silicon NPN transistor for use; V2 selects S8550 type silicon PNP transistor for use.
ICl selects NE555 type time base integrated circuit; IC2 selects LM7809 type three-terminal voltage regulator integrated circuit.
T selects 3-5W, the secondary voltage is I2V high-quality power transformer (should ensure long-term power supply without serious heat).
K selects JRX-l3F type 9V DC relay.