Tiny IV-21 VFD Clock
Hello, I have build this beautifull clock some time ago, the author have share all necessary stuff to buil it in hackaday.io website. I have encontered some problems that I have solved and I hope to help someone else:
All neccessary files taken from the above link can download from here
PCB
The JLCPCB PCB manufacter have reported to me a problem in traces space distance that is too small, so I have modified the gerber inaccording the of JLCPCB rules, in addition I have substitute the power connector.
Components
Parts List
- C1 0.1uF
- C2 22pF
- C3 22pF
- C4 0.1uF
- C5 33uF
- C6 100uF
- C7 0.1uF
- C8 0.1uF
- D1 1N5817-B
- DBG TSW-104-07-G-S
- H MOMENTARY-SWITCH-SPST-PTH-RIGHT-ANGLE
- J1 ICSP
- J3 DC_POWER_JACK-PJ-102AH
- L Red
- L1 2mH
- M MOMENTARY-SWITCH-SPST-PTH-RIGHT-ANGLE
- N LSP11
- P LSP11
- Q1 32.768kHz
- R1 10K
- R2 10K
- R3 1K
- R5 10K
- RFIL
- SP1 SPEAKER/AL60P
- SV1
- T1 3904
- T2 2N3904
- U1 MAX6921
- U1 DS1302S+
- U2 ATMEGA328P_TQFP
- X1 TSW-102-07-G-S
- Y1 16MHz
Because of I haven’t all neccessary component in SMD package, I have adapted some throught hole component to the PCB (see the pictutes above for detail) .
About DS1302S+, I have used a separate module that I have connected to PCB using wires.
IV21 pinout identification
A big problem that I have encoutered was pins identification of IV21 VFD valve. In the hackaday.io project post no mention how to do that. From here is a post where is described the pinout or you can download pdf datasheet in cyrillic 😉
But the problem was where is located pin 1? The pins apparently have the same distance between each others! Pins 1 and 10 are connected to cathod filament, so just use a continuity tester and when you find no resistance between 2 pins, you have found pins 1 and 10. After locating pin 1 you have to count clockwisw to locate pin 2,1…19.