Important changes to repositories hosted on mbed.com
Mbed hosted mercurial repositories are deprecated and are due to be permanently deleted in July 2026.
To keep a copy of this software download the repository Zip archive or clone locally using Mercurial.
It is also possible to export all your personal repositories from the account settings page.
main.cpp@2:11714802a55d, 2022-07-17 (annotated)
- Committer:
- marietjie
- Date:
- Sun Jul 17 18:14:09 2022 +0000
- Revision:
- 2:11714802a55d
- Parent:
- 1:011f0bdaa7f5
rev1_
Who changed what in which revision?
| User | Revision | Line number | New contents of line |
|---|---|---|---|
| marietjie | 0:28f2dba63d6c | 1 | /*---------------------------------------------------------- |
| marietjie | 1:011f0bdaa7f5 | 2 | A fictional IoT-enabled Ice cream machine dispenser arm state |
| marietjie | 1:011f0bdaa7f5 | 3 | The machine runs with an STM32F4 MCU; The Nucleo-F410RB is chosen for implementation, as it has serial communication, several digital outputs and 16 channel 12-bit ADC and more |
| marietjie | 0:28f2dba63d6c | 4 | |
| marietjie | 1:011f0bdaa7f5 | 5 | Operation: Ice cream machine dispenser arm sensor provides 0-3.3 V (assume based on operating voltage |
| marietjie | 0:28f2dba63d6c | 6 | of MCU) to one ADC pin on STM32F4 MCU. Voltage is based on position of dispenser arm. |
| marietjie | 0:28f2dba63d6c | 7 | - voltage > 1.65V implies the arm is pressed down |
| marietjie | 0:28f2dba63d6c | 8 | - voltage < 1.65V implies the arm is released |
| marietjie | 2:11714802a55d | 9 | To prevent rapid switching, hysteresis is introduced with a counter function, if arm is pressed down for more than x seconds, the digital output will go high. |
| marietjie | 0:28f2dba63d6c | 10 | |
| marietjie | 0:28f2dba63d6c | 11 | Requirements: |
| marietjie | 0:28f2dba63d6c | 12 | 1. Read ADC value and print over serial port |
| marietjie | 0:28f2dba63d6c | 13 | 2. Digital output pin high if voltage>1.65V |
| marietjie | 0:28f2dba63d6c | 14 | 3. Digital output pin low if voltage <1.65V |
| marietjie | 0:28f2dba63d6c | 15 | |
| marietjie | 0:28f2dba63d6c | 16 | Assumptions: |
| marietjie | 0:28f2dba63d6c | 17 | 1. The code can run at a low speed as ice cream machines do not dispense ice cream quickly |
| marietjie | 0:28f2dba63d6c | 18 | 2. Low accuracy and low resolution due to nature of ice cream machine dispensing arms |
| marietjie | 0:28f2dba63d6c | 19 | |
| marietjie | 0:28f2dba63d6c | 20 | Additional features |
| marietjie | 0:28f2dba63d6c | 21 | 1. Temperature of ice cream mixture is important, assume temperature sensor can provide analogue |
| marietjie | 0:28f2dba63d6c | 22 | voltage to MCU |
| marietjie | 0:28f2dba63d6c | 23 | 2. Level of ice cream mix in machine is important, assume a sensor can detect when the mixture drops |
| marietjie | 0:28f2dba63d6c | 24 | below a certain level, also be analogue voltage sensor output |
| marietjie | 0:28f2dba63d6c | 25 | |
| marietjie | 0:28f2dba63d6c | 26 | ADC data on MCU: |
| marietjie | 0:28f2dba63d6c | 27 | Value from 0.0 to 1.0, depending on input voltage between 0.0V and |
| marietjie | 0:28f2dba63d6c | 28 | 3.3V; ADC default settings |
| marietjie | 0:28f2dba63d6c | 29 | ------------------------------------------------------------*/ |
| marietjie | 0:28f2dba63d6c | 30 | #include "mbed.h" |
| marietjie | 0:28f2dba63d6c | 31 | Ticker readADC; //Allows timed interval of reading data on ADC lines |
| marietjie | 0:28f2dba63d6c | 32 | |
| marietjie | 1:011f0bdaa7f5 | 33 | //Serial pc(USBTX, USBRX); |
| marietjie | 0:28f2dba63d6c | 34 | Serial device(D8, D2); // tx, rx, default settings: 9600 8N1 |
| marietjie | 0:28f2dba63d6c | 35 | |
| marietjie | 0:28f2dba63d6c | 36 | AnalogIn DispArmIn(A0); //ADC input from dispensing arm |
| marietjie | 0:28f2dba63d6c | 37 | AnalogIn TempIn(A1); //ADC input from temperature sensor |
| marietjie | 1:011f0bdaa7f5 | 38 | AnalogIn LevelIn(A2); //ADC input from sensor detecting level |
| marietjie | 0:28f2dba63d6c | 39 | |
| marietjie | 0:28f2dba63d6c | 40 | float DispArm_data; //Dispenser arm data |
| marietjie | 0:28f2dba63d6c | 41 | float Temp_data; //Temperature data |
| marietjie | 0:28f2dba63d6c | 42 | float Level_data; //Mixture level data |
| marietjie | 0:28f2dba63d6c | 43 | bool ADC_ready; //Indicate data has been read |
| marietjie | 1:011f0bdaa7f5 | 44 | int counter; //Hysteresis for dispenser arm |
| marietjie | 0:28f2dba63d6c | 45 | |
| marietjie | 1:011f0bdaa7f5 | 46 | DigitalOut dout(A4); //Digital output to indicate if dispensing arm has crossed the halfway mark |
| marietjie | 0:28f2dba63d6c | 47 | DigitalOut led(LED2); //Digital output for general use on LED |
| marietjie | 0:28f2dba63d6c | 48 | |
| marietjie | 0:28f2dba63d6c | 49 | void ReadAnalog() |
| marietjie | 0:28f2dba63d6c | 50 | { |
| marietjie | 0:28f2dba63d6c | 51 | //Assume default AnalogIn read settings |
| marietjie | 0:28f2dba63d6c | 52 | DispArm_data = DispArmIn; |
| marietjie | 0:28f2dba63d6c | 53 | Temp_data = TempIn; |
| marietjie | 0:28f2dba63d6c | 54 | Level_data = LevelIn; |
| marietjie | 0:28f2dba63d6c | 55 | |
| marietjie | 1:011f0bdaa7f5 | 56 | if (DispArm_data>0.5f) //Use counter function to prevent rapid switching |
| marietjie | 0:28f2dba63d6c | 57 | {//Trigger output pin; Add this section here as it is one of the critical requirements. |
| marietjie | 0:28f2dba63d6c | 58 | counter++; |
| marietjie | 0:28f2dba63d6c | 59 | if(counter>5) |
| marietjie | 0:28f2dba63d6c | 60 | { |
| marietjie | 0:28f2dba63d6c | 61 | dout = 1; //Arm is pressed down |
| marietjie | 0:28f2dba63d6c | 62 | counter=0; |
| marietjie | 1:011f0bdaa7f5 | 63 | } |
| marietjie | 0:28f2dba63d6c | 64 | } |
| marietjie | 0:28f2dba63d6c | 65 | else { |
| marietjie | 0:28f2dba63d6c | 66 | dout=0; //Arm is released |
| marietjie | 0:28f2dba63d6c | 67 | counter=0; |
| marietjie | 0:28f2dba63d6c | 68 | } |
| marietjie | 0:28f2dba63d6c | 69 | ADC_ready=1; //ADC have been read |
| marietjie | 0:28f2dba63d6c | 70 | } |
| marietjie | 0:28f2dba63d6c | 71 | |
| marietjie | 0:28f2dba63d6c | 72 | int main() |
| marietjie | 0:28f2dba63d6c | 73 | { |
| marietjie | 0:28f2dba63d6c | 74 | //Initialise variables here |
| marietjie | 0:28f2dba63d6c | 75 | ADC_ready=0; |
| marietjie | 0:28f2dba63d6c | 76 | counter=0; |
| marietjie | 0:28f2dba63d6c | 77 | DispArm_data = 0.0; |
| marietjie | 0:28f2dba63d6c | 78 | Temp_data = 0.0; |
| marietjie | 0:28f2dba63d6c | 79 | Level_data = 0.0; |
| marietjie | 1:011f0bdaa7f5 | 80 | |
| marietjie | 1:011f0bdaa7f5 | 81 | readADC.attach(&ReadAnalog, 0.5); // the address of the function attached and the interval (0.5 seconds) |
| marietjie | 0:28f2dba63d6c | 82 | device.printf("\nIce cream machine state:\n"); |
| marietjie | 0:28f2dba63d6c | 83 | |
| marietjie | 0:28f2dba63d6c | 84 | while (1) { |
| marietjie | 0:28f2dba63d6c | 85 | if (ADC_ready) |
| marietjie | 0:28f2dba63d6c | 86 | { |
| marietjie | 0:28f2dba63d6c | 87 | //pc.printf("%f \n\r",ADCdata); |
| marietjie | 0:28f2dba63d6c | 88 | device.printf("Dispenser arm %f \n\r",DispArm_data); |
| marietjie | 0:28f2dba63d6c | 89 | if(Temp_data>0.7f) |
| marietjie | 0:28f2dba63d6c | 90 | { |
| marietjie | 0:28f2dba63d6c | 91 | device.printf("Ice cream mixture not cooling: %f \n\r",Temp_data); |
| marietjie | 0:28f2dba63d6c | 92 | } |
| marietjie | 0:28f2dba63d6c | 93 | if (Level_data<0.3f) |
| marietjie | 0:28f2dba63d6c | 94 | { |
| marietjie | 0:28f2dba63d6c | 95 | device.printf("Ice cream mixture level low: %f \n\r",Level_data); |
| marietjie | 0:28f2dba63d6c | 96 | } |
| marietjie | 0:28f2dba63d6c | 97 | ADC_ready=0; |
| marietjie | 0:28f2dba63d6c | 98 | } else {} |
| marietjie | 0:28f2dba63d6c | 99 | wait (0.2f); |
| marietjie | 0:28f2dba63d6c | 100 | } |
| marietjie | 0:28f2dba63d6c | 101 | } |