Thursday 13 December 2018

3D printing - battery cover for Samsung TV remote control - and tinyfab controller housings

Samsung telly remote battery cover:

Bloody annoying to discover several months ago that the battery cover had become detached and lost from the TV remote. Almost certainly it found itself on the rear lawn, having been chewed up and passed through one of the ducking fogs. It would have turned up by now if it had simply fallen on the floor.

I'd planned to model the thing up in Fusion 360 and flash one up on the 3D printer. Got out the calipers and made some measurements:


Then I thought it might be a sensible idea to check if it already exists on Thingiverse. Bingo! There are actually a few of them and I chose one that I thought looked reasonable


Printed one off but TBH, this probably wasn't the best orientation, as the only visible surface is the one that starts off in contact with the "raft". So when you remove the raft it looks crap.

In terms of the printing itself, this isn't bad for "fast" settings:




Did another one, this time with the visible surface uppermost. Sort of better, but despite being rotated exactly 180 degrees, the top surface has some unwanted layers, rather like a Fresnel lens.

Try again, this time with the part on its side. Here it is, not yet parted from its raft at the bottom, with the original part in the middle:


It's the nearest one and certainly comes out best. BTW - it's an oven glove:



I'll find out this weekend if it is actually any good as a battery cover....

Tinyfab controller:

In one of those senior moment / finger trouble episodes a month or so ago, I ended up buying a Tinyfab CPU replacement for the Cetus. I've barely used the Cetus and here I am changing the guts of it already.

This thing replaces the Arduino-like controller that sits on pin headers on the main Cetus controller (breakout) board. The main advantage of it is that it allows you to play with the firmware, unlike the Cetus controller which is closed and uses proprietary firmware. It's also got wifi, so (like the Cetus controller) you can talk to it without cables.

As it says on the site "This CPU board runs the smoothieware firmware so you can no longer use the UP slicer program. You can use popular gcode slicer like Sli3er, Cura* and send it to the printer via Repeiter-Host, as well as octoprint running off a raspberry pi."

It is offered as a "bundle" (hate that term) with an LCD panel that allows local control of parameters

Obviously you don't want this thing sitting on the table with wires everywhere, so a housing (3D printed) is the obvious solution. And of course, they have designed one which you can download from Thingiverse. Searching for "cetus lcd" brings it up:


Started printing these parts off. Here's the case for the display:



And the cover for the main housing:





Slight problem at this point, the sort that brings everything grinding to a halt. The initialisation procedure requires each of the 3 slides to bottom out as a sort of homing procedure. Mine started making a ferocious racket, requiring me to kill the power. Clearly some issue with the setup there, although I didn't change anything myself. This seems to be par for the course with these hobby grade machines. A quick search suggests this is a known issue with a simple(?) fix. For the Z axis, there is an adjustment screw but for the X and Y, you have to bodge it with some packing.

There's a Pootube video with silly music showing you how to tackle "calibartion":



One unusual feature of the MkII version of the Cetus is that it has no actual limit switches, instead relying on some form of stall detection. Having said that, the Tinyfab controller relies on real microswitches, so you have to retrofit those. The switches in the kit of parts come prewired with the correct connectors that plug into the legacy (MkI) limit switch headers. At least this should avoid the "calibartion" issues, if I can print off the Tinyfab parts first that is....

Naturally, you have to print out a set of modified parts that are used to mount the switches, replacing the original end caps etc. Here they are, printed out together (well, 4 of them actually) on a common raft. Came out nicely - this was actually done before the Tinyfab housing parts.


There are a few other things that I plan to print off from Thingiverse, such as a cable clamp for the hot end. Currently the cable to the head is simply a ribbon cable with no cable anchor. Every move of the head cycles the connections between the ribbon and the connector, so it won't be long before the strands start to fatigue. This looks like an improvement over nothing:


So, a few things to do before I can get my Tinyfab retrofit up and running....

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