Introduction
As already explained in the previous posts, the Meditech container includes many components surrounded by a small networks of different and specialized microcomputers and microcontrollers. A ChipKit PI board connected with the RPImaster main device manages a series of independent controls mostly related to the internal Meditech health status; the same micro controller board is also used to set several calibration levels of the probes.
Meditech should be easily controlled and managed by the user, that is expected to be a non high-skilled technical personnel. So the control panel is an internal automated device though to simplify the life of the operator enabling him to manage the different diagnostic systems without too much effort and without the need of a keyboard and mouse that are optional only in some conditions.
The control panel features
The following are the features supported by the control panel
Temperature control
An integrated heat sensor constantly controls the internal temperature (shown on request on the LCD control panel display). When the level reach about 40C the cooling fan is automatically started and the speed is increased if the heat level grows during the usage.
Parameters calibration
Depending on the user choices, the same analog potentiometer can be used to calibrate different probes, where needed (e.g. the microphonic stethoscope audio gain).
Probes activities
A series of leds shows the probes that are enabled and working.
LCD alphanumeric display
An alphanumeric LCD (based on the LCD Alphanumeric kit for Arduino and the software library adapted to work with the ChipKit board) using the I2C of the ChipKit PI micro controller board shows information, alarms, internal temperature etc.
IR receiver
This is the only tool directly connected to the RPImaster enabling the user to access the control panel features and settings from remote. This is useful as in many cases the probe settings should be managed by the operator while he is nearby the patient.
The micro controllers exchange data with the RPImaster device via the serial connection that has sufficient speed for simple commands exchange.
Fan control
The fan control is an automatic feedback in response to the internal temperature. The fan speed is controlled by a PWM signal managed by the micro controller and is independent by the entire process.
Lid open alarm
Lid open alarm is activated by a microswitch (the mechanical solution in these cases is more reliable then redundant electronic). If the devices components lid is opened while the system is running, it is shown an alarm on the LCD display then after x second (the delay duration should be tested experimentally) the micro controller sends a command to the RPImaster that initiates a total shutwon procedure of all the devices.
The following video shows the experimental preview of the test circuit just before it is converted in schematic and the content of the box organized in a proper way.
