Portable air pump ESP32 CS1237 Nokia_5110

Said it in front

I couldn't find the sensor model. I looked for a similar one. The sensor model in the code is wrong.

Please confirm before continuing

1. The open source circuits, programs, and models are not perfect, and I don’t want to update them. I need to improve them myself, so you need a certain amount of hands-on ability to copy the project. If you don’t know how to modify the software, you may need to tinker~

2. Circuit problem: 3 pull-down resistors are missing, namely Powerkey pull-up resistor, 10K, interface io and 3.3V; motor drive MOS, 10K, connected to the gate and ground; LED drive MOS, 10K, connected to the gate and land. (I don’t know why I thought there was no drop-down.) The key packaging is different from the actual use. I originally wanted to use metal patch keys, but I don’t have them at home. I used plastic ones so I didn’t have to make key caps and cut off the pins. , patch welding.

3. Software problem: There is a bug in CS1237 reading. If the last bit of the problem is 0, there is no interrupt to obtain Ready, resulting in a reading error when the chip is busy. Currently, it is a hard delay, and the reading is wrong 2 seconds before booting. For the LED switch button, I randomly found an IO port and soldered it. You can use io0 and just modify the definition.

4. Housing problem: There is a problem with the LED switch button and it cannot be installed. I removed some of the buttons and glued them on. The USB port and all button openings are small and may need to be polished to be larger. The two screw hole bosses that hold the motor in place are a little short.

5. Defects in the air pump itself: I suspect that this is the reason why this air pump went into the junk market without being assembled. The sensor is too close to the pump outlet, and the newly compressed high-temperature gas can easily enter the measurement cavity, causing the sensor temperature to rise and causing measurement errors. I put some silicone tubes in the channel entering the cavity to reduce the cross-sectional area of ​​the channel and reduce the temperature conduction. I don't know if it will help.

Requirement

Hardware:

Air pump, ESP32 (the SOLO I use, which was dismantled from electronic waste), small LED light bar, 2 18650 batteries, 2S lithium battery protection board (high current), 2S lithium battery charging board, 2 18650 battery boxes, PD decoy board (9V, according to the charging board), Nika5110 display (I regret using this, the conductive strip is so annoying, I think I can change it to another 128*64 screen), M2.5 self-tapping screws, silicone tube (Rubber sheets are also acceptable, for shock absorption), and other electronic parts. The shell is 3D printed, and I used PETG dark green. usb to serial port ttl, download program.

Software

VScode+esp-idf, JLC EDA Professional Edition, solidwork.

Schematic design instructions

The MOS does not have to be the model shown in the schematic diagram (it was designed at the beginning of last year, I forgot to select the correct model), both of them must be MOS above 15A.

Physical display instructions

The LED switch button is as large as the picture below. The wires are soldered to the circuit board.

There are two parts in 3D printing, the inner part and the outer shell. When printed, the inner part does not need support. The outer shell needs support at the screen position. I use a tree-shaped support, a thin tree.

I used the atmospheric pressure to calibrate the pressure. The mobile phone and watch learned the current pressure and read it once a day. The weather changed a lot during the two days when I was writing the code. The first day was 102KPa, the second day was 104kPa, and the third day was 106kPa. They were all approximate values. . There is a good APP called Mobile Physics Workshop, which is very useful. For example, you can know the frequency of PWM through the low-speed roar of the motor. I pumped my own bike to 50 PSI and measured it with a pump with a pressure gauge, which was pretty accurate. It would be better if there are other calibration methods. There is no temperature or pressure compensation or anything like that. The temperature is from the CS1237, which is also calibrated by the thermometer at home, so it may not be accurate. If you want to see the log, change log to info in menuconfig.

Operating Instructions:

Press and hold the M key to turn on the phone, and long press the M key to turn off the phone.

Click the M key to start/stop. Click the LED switch key to turn the light on and off.

When not started, click +- to switch presets. ★It is user-defined. The settings (including units) will be saved when exiting the set mode and will be remembered when the device is turned off. Others are not saved.

Double-click the M key to enter the set mode, and adjust the setting value through +-. Double-click again to exit.

Click the M key three times to switch the unit, kPa, PSI, Bar cycle.

After starting the mode, it automatically enters the set mode.

Automatically stops when the setting is reached.

Assembly details

Code

Electric_pump: electric_pump witg esp32 on esp-idf (gitee.com)

Cost

ESP32 costs 10 yuan + components 5 yuan + wires 5 yuan. The printing cost is 10 yuan to 15 yuan. I haven’t calculated the details. The others are below. In fact, it is not low either.

Shell

Appendix