DIY Moon Phase Dial

[Gina]

Making an anti-vibration mounting for the drive motor using offcuts from my observatory foam rubber tiles and a 3D printed frame.

[Gina]

All back together and the motor noise is less but there's still noise from the gears.  Not much improvement in fact.  I think it needs a rubber motor gear   Maybe when I get my Pilot 3D printer upgrade finished I can print a gear with different filament - something soft and flexible.

OR...  I guess I could use a timing belt instead of spur gears from motor to seconds wheel/shaft - a quiet option                                                                   

[Gina]

With the clock back on the wall the noise is not noticeably different from before   That was a waste of time then!

[saac]

Remember Edison Gina, he said he hadn't failed, (in reply to teasing from a journalist) he  just discovered lots of way it wouldn't work!

 

Jim

[Gina]

Ah yes

[Gina]

I've odered some TPE flexible filament to try.  A lot more expensive than ABS or PLA but I expect to use only a small amount for special purposes. eg. quiet gears and anti-vibration mountings.

[ChrisLX200]

I have a spool of that stuff and it prints quite well. Not the soft rubber you might expect though... adjust the flexibility with the % infill.

ChrisH

[Gina]

That's interesting Chris   I plan to use it with my Pilot 3D printer which now has a direct filament feed rather than Bowden which I don't think would work very well.

[Gina]

I thought I'd try reducing the delay between steps within the burst to a low value.  It changed from a brum brum to a very loud tick.  Next I tried increasing the delay again to see if I could change it to a less loud beep but at that point every stopped working   Now I'll have to do some faultfinding but I think I'll leave it for another day.

[Gina]

Seems to be another Nano virtually dead.  LEDs blink but can't upload to it.

[Gina]

Found a new Nano and soldered the two rows of pins to it and it takes uploads fine but installed in the clock it's not working.  Yes, I have uploaded the right sketch   The RTC module is powered (5v from Nano) but the motor doesn't run and the LED strip lights don't come on   I'm not having much success with my projects ATM!   Except for the clearing up - that's been going quite well   Thought I'd take a break from clearing up and doing something more interesting - didn't work.  May try a walk up the hill instead

[MarkyD]

I would start from basics and see if the blink sketch works

[Gina]

I have and it does   Next suggestion please   Actually, I do have some ideas.

[Gina]

Have the clock on my workbench (living room table ATM) and been testing with DMM.  But I'm having a problem as the Nano ATmega328 chip is getting hot - too hot.  The RTC module is working and the Nano responding to it - I have it running the inbuilt LED.  Tracing the 12v rail it gets to the electrolytic capacitor beside the stepper driver module but no voltage shows on the pin of the driver module soldered into the next hole in the copper strip on the circuit board, yet the solder joint looks alright - but it can't be as there's 12v across it.

I'm thinking one or both driver chips have blown.  Seems that the stepper driver must have a short from +12v to 0v so I guess I shall have to unsolder the stepper driver module.  When I was building the circuit I wanted to have the module plugging in as these are known to be prone to failure but I couldn't find suitable sockets.  The other driver is a ULN2003A which drives the LED strip.  I had planned to test the Nano outputs one at a time to see if either driver was shorting the output but I don't want to burn out the Nano whilst testing.

I have an idea   If I change the sketch so as not to drive the inputs to the drivers, if I'm right and it's a driver loading the chip, the chip should no longer overheat.  Then i can enable outputs one at a time to find the culprit.

[Gina]

Turning off the outputs has certainly stopped the chip getting hot but now the RTC module has stopped outputting its square wave and the output is a constant logic 1.  There is now 12v on the stepper driver module though.  Strange.  Think I'll give up for today...

[Gina]

Another batch of Nanos arrived in the post this morning to replenish my stock   10 for £20.  So I can blow Nanos till my heart's content

[Gina]

I'm just wondering how much of the electronics I have managed to blow up!!   I guess I'd better get back to some testing...

[Gina]

Disconnected the RTC module output square wave from the Nano just leaving the 5v supply (which read 5.01v on my DMM) and checked the output and it was a solid logic 1   So the RTC module is dead Maybe it would be easiest to start again with all new parts  

[Gina]

TPE filament arrived today and I tried it in the UP plus 2 printer for printing the motor gear.  It worked but the extrusion temperature was a bit too high as I expected and got rather a lot of whiskers between the teeth.  I cut these away, cleaned bits out of the bore and tried it on a stepper motor.  It fitted nice and tightly onto the motor shaft and I think might be alright if the motor is kept cool otherwise it will need a metal hub.  The teeth fitted nicely into the teeth of a previous seconds gear and will provide a nice springy drive.

I hope to get my Pilot printer working again soon and that also now has a 1.75mm extruder with direct, not Bowden drive, so should work with rubbery filament as well as ABS and PLA.  With this printer I can set the temperatures as required, unlike the UP with fixed temperatures.  I think this TPE filament would be good for some of the other gear teeth too to provide nice quiet gearing.  It would only be wanted for the bigger gears and the pinions could be ABS as it only needs one of a gear pair to be flexible.

[Gina]

Here's a photo of the TPE motor gear attached to a NEMA17 stepper motor.  The colour is described as "copper" but I would call it "chocolate"   Copper is redish and this is definitely brown.  And when it was printing it reminded me of piping melted chocolate onto an iced cake   It dribbled like molten chocolate.  I've ordered some blue TPE too.

[Pan Euro]

Definitely chocolate.

[Gina]

The blue TPE arrived this morning - nice colour   I may try that in the UP printer but I expect the result to be pretty much the same.  I need to finish off the upgrade to my Pilot printer and try printing at the right temperature.  OTOH I also need to sort out the electronics for the clock.  At least I managed to get some important business sorted out this morning so I have a free afternoon and evening to do what I like   The forecast is for some clear skies tonight so I might sort out my astro gear.  Decisions, decisions!!!

[Gina]

Been doing some testing and the ULN2003AN seems fine.  Without a Nano plugged in I tested it by applying +5v from bench PSU to the inputs and observed the LED lights.  Red, green and blue lights came on when the appropriate input was connected to 5v.  OTOH the RTC module with 5v power applied did not produce a square wave so is probably dead. 

I haven't yet tested the stepper driver module which needs two inputs and power supplies to work - Direction and Step and also both +12v to drive the outputs and +5v for the logic.  12v comes from the mains PSU so no problem.  I'll need to set up a test rig.

[Gina]

The website A4988 Stepper Motor Driver Carrier gives informaion about the stepper driver module.  It says the Direction and Step inputs must not be left floating so the Direction input can be connected to 0v and the Step toggled between 0v and 5v to step the motor.

Since the motor doesn't run with a new Arduino Nano with proper sketch, I think I have to assume that the driver module is now faulty and probably a waste of time setting up a test rig to test it.  I have 5 driver modules from the defunct Giant 3D printer project so I think the simplest thing to do is replace the existing module with a brand new one.  I don't think a damaged Nano would destroy the driver module other than outputting 12v on one or more of the module data pins.  I can check this by DMM before inserting the new driver module.

[Gina]

I was still having a problem with the LED lights until I commented out all code relating to the RTC but now they are working.