Tuya infrared voice remote control

Preparatory steps

1. Click the link below to register for the Tuya IoT development platform (old users can skip this)
https://t.tuya.com/AY1D3R8L5H

2. Open the link below and copy the infrared voice assistant development-free product solution, so that you do not need to create the product step by step and avoid building errors
https://pbt.tuya.com/s?p=8bffeb8d0fae80bd6f1821ecf1da2dc6&u=a1926a83dcee35f0711352b0b02be069&t=1

AI voice implementation architecture

Hardware circuit analysis

1. The main control part needs to be consistent with the IOT platform firmware configuration. After placing an order in the development-free way, the firmware cannot be modified. If you make an error, you can only fly the cable or change the board.

2. According to the chip manual, it has been tested and effective. Finally, an AO3401 was added to the back end to automatically switch to USB power supply when the USB is plugged in. If you use an old battery removed from your mobile phone like me, you can omit the charging chip and use D10. Prevent the battery voltage from flowing back into the USB interface and vice versa (currently the PCB is not added, you can change it yourself if needed)

3. For the LDO step-down part, due to the battery power supply, the star-level LDO AMS1117 is not suitable because the voltage difference is too high, so I chose a 500mv voltage difference one from Beiling (if you want to save costs, you can actually use a voltage regulator tube) Or resistor voltage division, the 3.3V here is mainly only used for function button input)

4. The module requires 5V power supply. Similarly, the battery voltage is not enough and needs to be boosted. Please refer to the chip manual for the circuit.

5. The design of the microphone speaker is based on the reference platform. For model selection, please refer to the attached information.

6. For infrared emission, we use six IR333-A infrared emitting diodes with a wavelength of 940nm , a forward voltage of 1.4V , and an operating current of 100mA . If you do not choose other infrared tubes of this wavelength, you can also

7. The infrared receiver uses 1 IRM -3638 (others in this series have been tested and are easy to use, such as: IRM-3638T-X) , which is used to receive 940nm , 38K modulated infrared signals. It has a built-in demodulation function and has a strong Anti-interference ability

Layout requirements

1. Main control part-mainly pay attention to the antenna part

Reduce antenna interference

To ensure optimal RF performance, it is recommended that the distance between the module antenna part and other metal parts be at least 15mm. Because M1 is used through the SMT process, it is attached to the main control board and used together with other components. Then the placement and placement of the PCB antenna will directly affect the RF performance. The following are our recommended placement locations, and the placement locations we do not recommend. It is recommended to use the placement positions of Plan 1 and Plan 2, with the antenna hollowed out outside the board frame or near the antenna. The performance is basically the same as the RF test performance of a single module. If the design is limited and the PCB antenna must be placed on the bottom board, you can refer to the placement method of Plan 3. The antenna is within the board frame, but there is no copper or wiring near the antenna. However, there will be some loss in radio frequency performance, approximately 1-2dBm attenuation. It is not recommended to use the placement position of Solution 4. The antenna is in the board frame and copper or wiring is placed under the antenna. RF signals will be significantly attenuated

2. For the boost power supply, it is recommended to refer to the recommendations in the chip manual as much as possible, which can effectively reduce the output ripple.

3. The recommended minimum distance between two microphones is more than 40mm to prevent echo interference.

Video demonstration link

https://www.bilibili.com/video/BV18U4y1T7qD