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SP7 pendulum assembly

I have ordered 3 separate pendulum movements from Aliexpress. They all show pictures that jibe with the instructions, but when they arrive, they have surface mount components instead of the large size caps and resistors shown in the instructions. The problem I am having is that they don't seem to have enough oomph to swing the pendulum far enough to engage the ratchet wheel. It swings, just not far enough. The bearings and mechanical portion of the clock seems to run well. Does anyone know a workaround or where I can find the appropriate pendulum driver? Any suggestions welcome. Thanks

3 comments

3 Comments

jmoore8733

I hooked it up to 6V and it works ok. Since I now have multiple units I hooked up others to see if it was a quality control issue and I just got a bad one. Turns out I got a bad two. Third one, however is chugging along nicely. Dunno what's up with the others as I am fairly ignorant of electronics. Thanks for the help and the great plans. Having a lot of fun building them.

Steve

Replying to

Good to hear you have a solution. The bad ones may have been one bad batch on AliExpress. I tried ordering 623 bearings from five different vendors on AliExpress. Three arrived in the same package and the other two appeared identical, essentially eliminating the "randomness" of the test.

I do plan on refreshing the SP7 clock at some point in the future. Options might include a larger battery cavity or a power input (either USB or 6V). A less sensitive ratchet that always pushed exactly one tooth as long as the pendulum amplitude was above the minimum seemed close. I never quite got it working right, but it always felt like there was a potential solution.

Steve

Sorry, I haven't ordered any for a while. Many of the modules currently on Amazon and AliExpress appear to be the same.

Try running the clock without the pawls. The original driver would build up a pendulum amplitude high enough to hit the end stops when running on 3V. This tells you that the bearings are good and the magnet is close to the coil. Adding the pawls adds enough friction to limit the swing to the desired amount. If you want to experiment, see if it will run on 5V or 6V.

The EM clock (SP7) and Coup Perdu (SP8) should be next in line for a refresh, but they could still be many months away. I ordered some new modules from Amazon (US$11 for 3) to test them.