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STM32通过光敏电阻检测光照强度，调节LEE亮度

花匠小妙招
2024-11-25 03:38

可以通过以下步骤实现在STM32中通过光敏电阻检测光照强度，并调节LED灯的亮度：

在STM32的代码中，使用ADC模块读取光敏电阻的电压值。

将电压值转换为光照强度值。这个转换需要根据具体的光敏电阻特性来确定，一般需要进行一些实验来获取转换公式。

使用PWM控制LED灯的亮度。可以使用CubeMX来配置PWM模块和GPIO引脚。

根据光照强度值来控制LED灯的亮度。可以将光照强度值与一个预设的亮度范围进行比较，然后将比较结果转换为PWM的占空比来控制LED灯的亮度。

下面是一个简单的示例代码：

// 定义光敏电阻的引脚号和ADC通道号 #define PHOTOCELL_PIN GPIO_PIN_0 #define PHOTOCELL_PORT GPIOA #define ADC_CHANNEL ADC_CHANNEL_0 // 定义LED灯的引脚号和PWM模块 #define LED_PIN GPIO_PIN_5 #define LED_PORT GPIOA #define LED_TIM TIM2 #define LED_CHANNEL TIM_CHANNEL_1 // 定义光敏电阻的转换公式 #define VREF 3.3 // 单片机的参考电压 #define R_DIV 10000 // 光敏电阻和电阻的电阻值 #define MAX_LUX 1000 // 光照强度的最大值 float map_f(float x, float in_min, float in_max, float out_min, float out_max) { return (x - in_min) * (out_max - out_min) / (in_max - in_min) + out_min; } int analogRead(ADC_HandleTypeDef *hadc, uint32_t channel) { ADC_ChannelConfTypeDef sConfig = {0}; sConfig.Channel = channel; sConfig.Rank = ADC_RANK_CHANNEL_NUMBER; sConfig.SamplingTime = ADC_SAMPLETIME_239CYCLES_5; if (HAL_ADC_ConfigChannel(hadc, &sConfig) != HAL_OK) { Error_Handler(); } HAL_ADC_Start(hadc); HAL_ADC_PollForConversion(hadc, 100); int val = HAL_ADC_GetValue(hadc); HAL_ADC_Stop(hadc); return val; } void setLedBrightness(TIM_HandleTypeDef *htim, uint32_t channel, int brightness) { TIM_OC_InitTypeDef sConfigOC = {0}; sConfigOC.OCMode = TIM_OCMODE_PWM1; sConfigOC.Pulse = brightness; sConfigOC.OCPolarity = TIM_OCPOLARITY_HIGH; sConfigOC.OCFastMode = TIM_OCFAST_DISABLE; HAL_TIM_PWM_ConfigChannel(htim, &sConfigOC, channel); HAL_TIM_PWM_Start(htim, channel); } void setup() { HAL_Init(); __HAL_RCC_GPIOA_CLK_ENABLE(); __HAL_RCC_ADC1_CLK_ENABLE(); __HAL_RCC_TIM2_CLK_ENABLE(); GPIO_InitTypeDef GPIO_InitStruct = {0}; GPIO_InitStruct.Pin = PHOTOCELL_PIN; GPIO_InitStruct.Mode = GPIO_MODE_ANALOG_ADC_CONTROL; GPIO_InitStruct.Pull = GPIO_NOPULL; HAL_GPIO_Init(PHOTOCELL_PORT, &GPIO_InitStruct); GPIO_InitStruct.Pin = LED_PIN; GPIO_InitStruct.Mode = GPIO_MODE_AF_PP; GPIO_InitStruct.Pull = GPIO_NOPULL; GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW; GPIO_InitStruct.Alternate = GPIO_AF1_TIM2; HAL_GPIO_Init(LED_PORT, &GPIO_InitStruct); ADC_HandleTypeDef hadc1 = {0}; hadc1.Instance = ADC1; hadc1.Init.ClockPrescaler = ADC_CLOCK_SYNC_PCLK_DIV2; hadc1.Init.Resolution = ADC_RESOLUTION_12B; hadc1.Init.ScanConvMode = DISABLE; hadc1.Init.ContinuousConvMode = DISABLE; hadc1.Init.DiscontinuousConvMode = DISABLE; hadc1.Init.NbrOfDiscConversion = 0; hadc1.Init.ExternalTrigConvEdge = ADC_EXTERNALTRIGCONVEDGE_NONE; hadc1.Init.ExternalTrigConv = ADC_SOFTWARE_START; hadc1.Init.DataAlign = ADC_DATAALIGN_RIGHT; hadc1.Init.DMAContinuousRequests = DISABLE; hadc1.Init.EOCSelection = ADC_EOC_SINGLE_CONV; if (HAL_ADC_Init(&hadc1) != HAL_OK) { Error_Handler(); } TIM_HandleTypeDef htim2 = {0}; htim2.Instance = LED_TIM; htim2.Init.Prescaler = 0; htim2.Init.CounterMode = TIM_COUNTERMODE_UP; htim2.Init.Period = 999; htim2.Init.ClockDivision = TIM_CLOCKDIVISION_DIV1; htim2.Init.RepetitionCounter = 0; if (HAL_TIM_PWM_Init(&htim2) != HAL_OK) { Error_Handler(); } setLedBrightness(&htim2, LED_CHANNEL, 0); } void loop() { int val = analogRead(&hadc1, ADC_CHANNEL); float voltage = val * VREF / 4095.0; float resistance = R_DIV * (VREF / voltage - 1); float lux = map_f(resistance, 0, 10000, 0, MAX_LUX); int brightness = (int)(lux / MAX_LUX * 1000); setLedBrightness(&htim2, LED_CHANNEL, brightness); HAL_Delay(100); } int main() { setup(); while (1) { loop(); } }

以上代码仅供参考，实际应用中还需要根据具体需求进行修改和完善。

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