Hardware Contributor

@andrew Looks as though your new nema steppers either have encoders or else those are knobs for manually jogging. Aside from that, it looks generally stiffer due to all metal with no plastic.

No matter which one you pick there are tradeoffs. For instance, one of the nice things about the nrf24 is that you can update your mysensors sketch over-the-air. If you have dozens of nodes which need updating, that's a big convenience and time saver.

@NeverDie said in The Harvester: ultimate power supply for the Raybeacon DK:

Edit: This guy found another couple of possibilities as to what the E50D chip might be: https://www.electroschematics.com/pfm-module-circuit-surgery/

I have the same board as this guy. I removed the LED and resistor because they are on the input side, so they are almost useless anyway. For a board such as this, with a promised 0.9v startup voltage on the input side and a promised 5v on the output side, they really should have been attached to the output, not the input, to show roughly when it is that the board is producing useable output.

At a 20mv "keep alive" input voltage, the input measures 0.5ma using a uCurrent Gold. That means the keep alive energy is 10 microWatts. Offhand, for the application we've been discussing on this thread, I suspect that number is too high to be practically useful, because at only 20mv input we'd be collecting far less than 0.5ma current from a tiny panel. At least now we know.

I've confirmed Julien's results. I procured a board that's inferior to his but with the same chip on it, and with no load other than its LED it can remain operational as low as 15mv. With that as the input voltage, the output voltage is around 640mv, so I think the reason my board can't survive on less than 15mv is that when the output voltage dips below about 600mv then the chip no longer has enough voltage to switch. Compared to other off-the-shelf chips, this is an impressive result, and even more so considering that these chips only cost around 8 cents each in small quantities.

Edit: This guy found another couple of possibilities as to what the E50D chip might be: https://www.electroschematics.com/pfm-module-circuit-surgery/

Julien stumbled across an inexpensive PFM boost converter board which he demonstrates is able to boost 65mv up enough to light a red LED:
eBay Cheap & Cheerful: #3 - DC/DC Boost Module 5V Out – 07:44
— Julian Ilett

I can't discern from the video what the minimum start-up voltage was, but it's quite a surprising finding anyway, because on its face it would appear to outperform most of even the energy harvesting chips on the market with respect to minimum operating voltage!

Edit: In a subsequent video, Julien found that the start-up voltage was 560mv (the datasheet only promises 0.9v as the minimum, so maybe Julien got lucky with his particular device):
Update: Cheap 5V Boost Converter Performance – 06:58
— Julian Ilett

but he's able to keep it running (albeit with just a 1.2v output and little to no load) on what he says is an input voltage of as little as 10mv. That matters because by keeping it running it sidesteps the start-up voltage requirement, and if the input voltage rises it can start being useful much sooner than having to wait for a minimum 0.56v input voltage to be reached. What would be interesting to know is just how much power is required to keep it running, even if only just for this purpose.

The switching chip is the E50D, which Julien's research indicates may be a CE8301.

The product listing for the step-up that the OP is using says:

Sucks the juice out of your batteries.

Sounds like it delivers on what it promises....

I found a good "once and done" lubricant for my CNC called Krytox. It's made by Dupont, is non-toxic, never dries out, and is non-reactive with just about everything. It is more or less liquid teflon (PTFE). It comes in a wide spectrum of different viscosities. I'm using GPL105, but I think for a CNC one could argue for using a version that's a least slightly more viscous (i.e. GPL106 or higher).

There also exists grease versions of Krytox, so perhaps (?) that would be even better. In general, for any given lubricant, how does one decide what the right viscosity is to use?

I've played around with the Ustepper-S now, and as near as I can tell, it is working correctly in closed-loop mode without issue. After the execution of each command, it shows error of 0.00, and it maintains closed loop operation to maintain its position even after the execution of the command, as it should. In my testing, Servo42A fails to do that, as well as having other problems, including lack of response to posted github issues.

Ustepper-S incorporates PID, so it should be able to do rapids and yet stop exactly where it should. Again, my initial impression is that seems to be the case.

I'm ordering UStepper-S for the x and y axis as well, which unfortunately will again take weeks to receive. However, I expect this will be the last stepper driver upgrade that I will ever need to do. If I later decide to upgrade to NEMA-23, the same UStepper-S can be used to drive it and only a different bracket would be needed to position it on the back of the NEMA-23.

I received some Sharpie-Oil "Extra Fine" pens. Testing them, they have a 1mm line width, so they'd be no good for filling in features smaller than that. AFAIK, they have the smallest tips in the Sharpie-Oil series.

I received the 16-bit closed-loop uStepper hardware from Denmark, so I'll be testing that sometime soon. I intend to use it on the z-axis, since accuracy on depth of cut is critical. If even this is still not enough, then I'll work harder to identify the source of the error and, if appropriate, consider stronger measures like low run-out collets, low-runout bits, ball-screws, tighter linear rails and/or tracking absolute position with a DRO and/or possibly a different spindle.

@Joerideman said in CNC PCB milling:

@NeverDie I saw an YouTube video screenprinting. That guy noticed that semi transparent sheets work better than transparent sheets. Ink holds better or something.

I can actually try this one out. Because afteral. We want that 0.4mm pitch right?

I just need to find something to put the paint on.

Which thing are you planning to try? Sharpie-Oil on a semi-transparent sheet, or the uv resistant inkjet ink, or...?

For enhanced laser printing I found this: https://ikonartstencil.com/toner-enhancement-spray/
though I have no idea how well, or even if, it works.