Call for submissions | IoT disinfection night light gas alarm

I haven't updated for a long time. Let's make a simple little thing.
The main control uses ESP8266 and the APP uses "Dian Deng Technology". It is a simple multifunctional IoT small production, designed for kitchens, corridors, etc.
 
1) Night light function, photoresistor (C125631) detects light. Use pyroelectric (digital pyroelectric sensor RDB226-S) or radar module (LD1020, TB purchase) to choose one of the two, choose the best.
It has been verified that the use of LD1020 radar module is better than pyroelectric, and the shell does not need to be opened. The price is also cheap (3.5 and free shipping).  
LED uses 6 series and 3 parallels (4000K Ra95 high color rendering, C516132 is recommended), the color temperature is comfortable. Use constant current boost drive, maximum 5W.

 

2) Ultraviolet disinfection lamp, ultraviolet LED is much cheaper now, more than 2 yuan per piece. I used 12 275+395NM 3-5mW LEDs (C909692). Constant current boost drive.
This lamp is UVC UVA dual wavelength, here UVC UVA is connected in series, UVC VF 6.5V +UVC VF 3.2V=9.7V. So I use boost drive SGM3732 (C116578). The current is controlled at 40mA. 12, two in series and six in parallel. So the drive current is 19.4V 240mA.

 

3) Gas alarm, using MP-2 sensor. Detection alarm for smoke, methane, propane.

 

4) Thermometer, using 10K 3950K thermistor (C279936).
 

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Hardware part:
Because the power is relatively large, battery power is not considered, and USB power is used directly.

The light board and main control are separated into two boards, and the light board uses an aluminum substrate for easy heat dissipation.
The light board and the main board are connected by 1.0mm 16PIN fpc cable.
The light board has three LEDs, red, warm white, and ultraviolet.

 
ESP8266 is the main control, the gas sensor uses MP-2 as analog output (C242497), the temperature uses a 10K 3950K thermistor (C279936),
the ambient light uses a photoresistor, and the power supply voltage. There are four analog signals, and ESP8266 has only one AD, so a CD4051 analog switch is used.
The buzzer uses a passive buzzer with a loud sound.
(After installing the shell, it was found that the photodiode was drawn wrong up and down after debugging. It can be used but the effect is not good, and it is too far away from the shell opening, resulting in insensitivity, so it is better to replace it with an ordinary photoresistor C125631)
 
 
 

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Shell part:
The shell finally arrived the day before the deadline and was installed. X resin, less than 10 yuan, good quality.
 
 
 
 
 
Heat the nut with a soldering iron and insert it into the hole. It is recommended to adjust the soldering iron tip to 250 degrees and use high-temperature tape to do it slowly (I was too anxious and overturned here and cracked a hole).
 
 
 
 
 
The front is printed on the (milky white frosted diffusion board finished acrylic 2.0) panel.
The transmittance of ultraviolet LED is low, so the acrylic is slotted.
 
 
The two magnets of 4*12*2 on the back are glued to the slot with a little red glue. It can be sucked on the refrigerator or something.
 



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Software part:
The program is written using Arduino of Dian Deng Technology, see attachment.
 
The configuration of the APP end is as shown in the figure below.
 
 

Control logic:
 
Night light, when the light is dark, it senses the human body, lights up, delays 30S and turns off, and continues to delay +30S when sensing the human body. It can also be turned on remotely by mobile phone (brightness is adjustable).
 
Direct ultraviolet radiation is harmful to the human body, and it needs to be turned on remotely by mobile phone (ultraviolet intensity is adjustable). After turning it on, the red light flashes to remind people to leave, and then it can be turned on again. If the human body is sensed during operation, the UV light will be turned off and the red light will flash until there is no human body sensing and it will continue to turn on.
 
Gas alarm, alarm above 500ppm, buzzer, red light flashing, remote mobile phone display. Manual

 


confirmation is required to turn off the alarm. Temperature alarm, alarm above 45 degrees, buzzer, red light flashing, remote mobile phone display. Manual confirmation is required to turn off the alarm.
 
Shell:
Acrylic panel plus 3D shell is designed, acrylic panel is waiting for arrival, 3D shell is waiting for proofing.
 
Debugging precautions:
 
LED driver R48 R43 is not soldered during debugging to make the LED drive current smaller to avoid flashing. It also avoids insufficient power supply when downloading via USB on the computer, resulting in failure to download.
 
Direct ultraviolet rays are harmful to the human body, pay attention to protection, it is recommended to wear anti-ultraviolet glasses, and a layer of tempered film can be covered on the light board. It is known that glass can block ultraviolet rays.
 
There is no gas or lighter at hand, so alcohol is used to test the gas sensor (butane gas tank was found later).
 
Complete shell test video, https://www.bilibili.com/video/BV1yk4y177bb/