Multi-point water level detection scheme based on TM601
Introduce the TM601 chip
TM601 This chip is a capacitive detection chip designed based on 8051 single-chip microcomputer. Its storage resource is 256B + 8K; the power supply voltage is 3--5V. The chip can support two output modes: IIC output and one-to-one output. Eight o'clock water level detection.
The chip has strong anti-interference ability and stability.
How to use
1. According to TM601's schematic diagram and PCB drawing board, proofing, welding test.
2. The demo board can be installed and tested. Note: When the demo board and the device are installed, the two must be tightly connected, and there must be a gap. When the device needs to be non-metallic, the thickness should be within 3mm as best as possible, preferably within 5mm. The detection liquid should be water, and the liquid should not be too viscous.
3. The most convenient place to use this solution is the debugging sensitivity. This sensitivity can be automatically corrected by pressing the button. For example, when you want to detect the water level at this point, when you press the button at the current water level, you can use the current capacitance value as the reference. In the capacitance value recording chip, when used, the presence of water can be detected when the capacitance value exceeds the current capacitance value, and vice versa. This solution is very accurate.
4.Test process and calibration method
① When the demo board is corrected, the power supply voltage is DC 9.2v.
② Never connect 9.2v and GND.
③ When pressing the button for calibration, never press and hold.
(1) The four PAD faces of the circuit board are closely attached to the wall of the container containing the liquid to be tested, the four PADs are aligned with the four liquid levels to be tested, and the four PADs are T1, T2, and T3 in order from top to bottom. , T4 (labeled on the board);
(2) Adjust the liquid in the container so that the liquid level reaches the first liquid level, which is the position of T1;
(3) After powering on, press the white button in the lower right corner once within three seconds, the indicator D1 flashes three times for calibration, and the third sensitivity is used as the final sensitivity. After D1 flashes three times, it stays on, indicating that Calibration succeeded. No other operations are required during the flashing of the light;
(4) adjust the liquid in the container so that the liquid level reaches the second liquid level, that is, the position of T2 is automatically turned off at this time;
(5) Press the white button twice, and the indicator D2 flashes three times for calibration. After D2 flashes three times, it will stay on, indicating that the calibration was successful;
(6) When checking T3, T4, the method is the same as above.
This solution has simple design, strong practicability, low cost, and extremely high detection accuracy. Suitable for water dispenser, coffee machine, humidifier, atomizer and other products that need water level detection.