QS-30 four-digit Nixie tube clock

QS-30 Nixie Tube Clock

Satisfy your fantasy of world line change rate detector with less money...

By the way, if you want to ideally restore the World Line Change Rate Detector, it can easily cost thousands. The main reason is that Nixie tubes are too expensive to buy.

When designing this project, the main consideration was to use many component modules on the handle, so some selections may not be so suitable.

• basic plan

MCU:STM32F030K6T6

Power management: DC-12V input, the 180V required by the Nixie tube is obtained through the max1771 boost, the 5V required by the driver chip is obtained through the 7805, and the 3.3V required by the microcontroller is obtained by 5V through the classic ams1117 step-down.

External clock module: DS3231

Other peripherals: ESP8266 WIFI module (ESP01S)  

Nixie tube driver: 2*74HC595 + 4*K155ID1

• Some known issues and instructions

1. When the four tubes are fully turned on for a long time, the MOS tube in the DC-DC circuit generates a lot of heat (to the point where it feels hot when touched), but after two months of testing, it was found that it does not affect the overall work. If improvement is needed, firstly, replace the inductor L1 in the DC-DC boost circuit with an integrated inductor instead of the shielded inductor used in my picture. The latter has poor high-frequency characteristics; secondly, replace the inductor L1 with a smaller on-resistance. And try adjusting the value of the feedback resistor.

2. The ESP01S module I purchased was never successful in debugging AT firmware, so I did not write this part of the function, but I directly used the USB to serial port module to debug (the specific problem is that the serial port print information is only received when powering on) , all other AT commands will not respond after that), so in principle, there is no problem with the circuit design of the wifi module on the PCB. You can write the relevant code yourself if you need it.

3. My two 74hc595s were designed to share stcp and shcp lines, but the data lines were not cascaded but used two ios respectively. Later I felt that this was just one fell swoop (I don’t know if I was full at the time) Why is it designed like this?), please pay attention when writing the code yourself.

4. K155ID1 is sold in only a few stores on Xobao. This thing is a high-voltage decoder. The normal price is 15 yuan per piece. SN74141N can also be used as a complete replacement for K155ID1. However, I have tested that 80% of the SN74141N on Xobao is fake. Goods (not resistant to high voltage, breakdown when powered on).

• cost

(QS-30 four) 35*4 + (K155ID1 four pieces) 15*4 + (MAX1771 and low on-resistance MOS and inductors and other uncommon components) 30 + (DS3231 module) 20 + (miscellaneous) 20= 270 RMB

The f030k6t6 only costs a few yuan a piece. I used this one because I bought too much before. The other common components such as resistors, capacitors, LDOs, etc. were not included in the cost. What needs to be noted is the DS3231 module. The price of this thing seems to have increased now. I still use the ones I used before. Bought inventory...

If you still want to save costs, you can only replace K155ID1 with a high-voltage triode such as A42. You can save about forty, but this will bring about wiring and welding challenges of more than a hundred triodes and resistors. I still don’t want to. It is better to save this money (I have also tried this solution, and the conclusion is that it can be used but not recommended).

• PCB description

There are two parts of PCB. UP is the circular part where the Nixie tube is placed (corresponding to the schematic sheet 2), and DOWN is the main control base (for the schematic sheet 1). The two PCBs are connected through 1.27mm*24pin pin headers and female headers.

• Attachment description

(The project was compiled on STM32cubeide)

QS30.7z is the entire project engineering file

QS30_setT.hex is the firmware used to set the time for DS3231 (it was originally planned to set the time through the wifi module every time it is powered on, but eso01s did not adjust it, so we had to make this decision)

QS30.hex/QS30_t.hex is the firmware during normal use, but I forgot which one it is... (There is a firmware with a protection function that does not display for a period of time. The specific time period is from 7 a.m. to It will not be displayed at 11 o'clock, 2 to 5 p.m. and after 12 p.m.)

The firmware can be directly burned in and used.