Skip to main content

ESPCLOCK4 - Implementation

I have uploaded the final code for ESPCLOCK4 to GitHub. Full details and schematic at the repository.

I have also created 2 prototypes, 25cm and 38cm clocks: 





I am quite happy with this version. It is much easier to debug (by using a dev board with the UART intact during development, and switching to one with the UART removed to save power for production), and very straightforward to implement on a prototype board. It also uses very few external components, but is equally power efficient.

Future enhancements will include:

- Adding an external clock crystal to eliminate the RTC_SLOW_CLK drift.

- Using C to write the ULP code. Assembly code is tedious and error-prone.

Labels:

Comments

  1. Ruxton3 January 2022 at 06:33

    Have you seen the recentish wifi clock movements from china? I think someone at a movement manufacturer might've been following your work ;)

    ReplyDelete
    Replies
    1. Random Sequence3 January 2022 at 14:02

      No I haven't! Must have been a recent development. At ~$75 for the 12-inch model, it's a little too rich for my taste. I will hunt around for reviews and try to figure out how it works. Very interesting! Thanks for the info.

      Delete
    2. Random Sequence3 January 2022 at 16:06

      Preliminary research shows:

      1) WiFi clock movement uses 2 x AA alkaline
      2) Claimed battery life of 1 year
      3) Uses sweeping clock movement
      4) Synchronizes once a day
      5) Stops at midnight every day to preserve battery life, and restart next morning. Can be changed through web interface.
      6) Connects to NTP for network time

      Delete
    3. Ruxton3 January 2022 at 19:44

      Yeah they're about $28 here out of the bay, I got one on the way just to see how it works. But your new 4 design is probably gonna work better. Out of interest why did you stop doing NTP queries?

      Delete
    4. Random Sequence4 January 2022 at 00:45

      NTP is the easy part, since that just gives you the UTC time. You still need to convert it to local time based on your timezone, and _that_ is the big hairy monster. No easier way then to outsource this task to a machine running a full OS that takes care of NTP + TZDB + DST info all in one place.

      Delete

Post a Comment

Popular posts from this blog

Update: Line adapter for Ozito Blade Trimmer

Update (Dec 2021): If you access to a 3D printer, I would now recommend this solution , which makes it super easy to replace the trimmer line. I have been using it for a few months now with zero issue.
5 comments
Read more

Attiny85 timer programming using Timer1

This Arduino sketch uses Timer1 to drive the LED blinker: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 /* * Program ATTiny85 to blink LED connected to PB1 at 1s interval. * Assumes ATTiny85 is running at 1MHz internal clock speed. */ #include <avr/io.h> #include <avr/wdt.h> #include <avr/sleep.h> #include <avr/interrupt.h> bool timer1 = false , led = true ; // Interrupt service routine for timer1 ISR(TIMER1_COMPA_vect) { timer1 = true ; } void setup() { // Setup output pins pinMode( 1 , OUTPUT); digitalWrite( 1 , led); set_sleep_mode(SLEEP_MODE_IDLE); // Setup timer1 to interrupt every second TCCR1 = 0 ; // Stop timer TCNT1 = 0 ; // Zero timer GTCCR = _BV(PSR1); // Reset prescaler OCR1A = 243 ; // T = prescaler / 1MHz = 0.004096s; OCR1A = (1s/T) - 1 = 243 OCR1C = 243 ; // Set to same value to reset timer1 to
2 comments
Read more

3D Printer Filament Joiner

I have been looking at various ways of joining 3D printing filaments. One method involves running one end of a filament through a short PTFE tubing, melting it with a lighter or candle, retracting it back into the tubing and immediately plunging the filament to be fused into the tubing: One problem with this method is that you can't really control the temperature at which you melt the filament, so you frequently end up with a brittle joint that breaks upon the slightest bend. Aliexpress even sells a contraption that works along the same line. As it uses a lighter or candle as well, it suffers from the same weakness. I am not even sure why you need a special contraption when a short PTFE tubing will work just as well. Another method involves using shrink tubing/aluminium foil, and a heat gun: But a heat gun is rather expensive, so I wanted to explore other alternatives. The candle + PTFE tubing method actually works quite well when you happen to melt it at the rig
1 comment
Read more