marcoreps

Laser driver on GitHub

With the 20 projects going on at the same time, I thought I should at least take the time and wrap this up nicely and professionally: 

https://github.com/marcoreps/laser_driver

Maker Faire Hannover next week

Thought I'd go with the tradition and make a new gimbal for the occasion - but the BNO055 accelerometer seems to be a less than ideal candidate ...

WIth a fourth axis I wanted to try and cancel out the z-axis (height) movements that other gimbals can't compensate. For that I don't have to maintain a constant height practically, it would be good enough to just smooth motions.

It's not quite ready yet, but got a lot better since the first attempts 2018-09-08 23:25:06 +0000 UTC View Post

I am sensing a new trend in the vaping industry

Disclaimer: The thing is probably not going to last long when desoldering fluxy joints, but the effect just had to be captured ...

Beginning to feel confident about a Tektronix video

Some of the niche features of this thing are still beyond me, but I think now that I have a reference spectrum analyzer, a DIY logic probe, a DIY differential probe and an active probe, I can finally dare to say a few things about this scope.

The sweep generator in this case is a Chinese ADF4351 board ( https://www.banggood.com/35M-4_4GHz-P...

Dexter inquires about delayed walkies

Couldn't put this down unfinished :L

Moai resin printer with actual laser and galvos instead of LCD or DLP! Took 5 hours to assemble and generated 60 GB of raw video footage. That has  already been documented extensively tho.

What hasn't are some mods, like a higher power laser, different vat materials like  FEP for exotic resins (ceramic?) an f-theta lens for uniform focus in a larger area ...

I hope I can make a Formlabs-killer for half the price in the end.

2018-09-04 19:46:04 +0000 UTC View Post

A sign of life from the new output board

So this baby did not burst into flames right away AND the cv portion of the circuit which I have already populated seems to kinda work. For the current limits I'll have to find the right component values in some cases by scientific trial and error.

Goal for this month: Make FPGA put out waveforms at a couple of kHz and have them control the output board. I would expect that by itself to be an exceedingly boring video, so the FPGA project video (scheduled for the 19. September) might b...

One more time: Laser driver is done

I have announced this before, when I finished my 2-stage constant current driver, that used an energy efficient DC-DC converter and a precise linear regulator.

Now I've finally managed to take control over the DC-DC converter and made it put out constant current! It's still scary, because 40A and humming things often proclaim imminent explosions. But the temperature looks fine and the absence of big heat sinks shows reasonable energy efficiency.

A shiny but shallow RS Pro video

Originally I wanted to include the new OSMU board in this video, but I've agreed to give RS Pro all usage rights for it. So I kinda cheaped out in the last second to give them something less important ... I hope it doesn't feel as rushed as it was?

a concentrate, professional, focus

Got all the DIY footprints right, gg ez :)

High res: https://imgur.com/a/KdjCpl0

Those right-angle SMD .1" pin headers are a bit expensive, as are the 8 LTC6090. But if this attempt works, it'll be a great foundation for further optimization.

Someone in the Discord chat thinks, that those MOSFETs will not be abl...

OSMU boards and non-OSMU video tomorrow

bit of a noisy video until then ... I absolutely need to get back into synthesizers after this whole CNC and laser business is concluded

Don't trust cheap switching power supplies

Happy to report that ODrive survived, but that's luck. I think I'll throw out or at least mark all PSUs that do something like that ...

Also got OSMU parts! PCBs and a new video coming next week. Originally I wanted to make that video about the new OSMU output stage, but cc laser driver might fit even better?

Particulate matter sensor vs Solder fumes

It detects PM1.0, PM2.5 and PM10 concentrations in µg / m². With solder smoke it detects mostly the largest PM10 category which is a relief because it doesn't get into the body as easily.

https://en.wikipedia.org/wiki/Particulates

Also: I ordered OSMU boards :)))) HYPE HYPE HYPE

2018-08-22 19:07:15 +0000 UTC View Post

Moving components and traces around

is all I've done this weekend. And I enjoyed every bit of it 😌

There's something therapeutic in finding arrangements that are electronically sensible and symmetrically aesthetic at the same time.

But who is Richard Wallin? ...

What makes a good fiber lapping puck?

Another thing I haven't forgotten: The fiber laser and driver ... I wanted to switch to an even higher grit lapping film or paste and a disk for holding the ferrule at a constant angle.

Such a disk is a bit of specialty tool and inherently expensive. So I thought I'd try and DIY one with a 5 cent coin and the amazing dc-drill-press. Since I seem to have the perfect diameter drill bit, I can now also make a heat sink for the ferrule which is fantastic.

Another concern: Some say, I have sp...

KX voltage reference assembled ✔️

like 5 minutes ago. That and the lack of all shielding might be causing a little bit of of noise. Or I screwed up somewhere, which is particularly easy with melty film capacitors and tight guarding traces.

Full documentary coming soon to a YouTube channel near you. As soon as OSMU stuff is ordered :)

Can IL300 be a floating voltage source? pls?

I am putting a lot of trust in these linear 'opto-isolators': https://www.vishay.com/docs/83622/il300.pdf

But I doubt they can replace these voltage sources: http://tinyurl.com/y9pr28t7

It would be too good if they did https://imgur.com/a/1rVQi23

If the open circuit...

Resistors mean business when they have certificates

5 months lead time and 200 bucks for these beauties! The metal can ones are hand-crafted and hermetically sealed. And that's only accessories in the quest for an ultra-stable voltage reference.

The total accuracy of around 0.01% is secondary, it's the low temperature coefficient of ± 0.05 ppm/°C that makes these so special.

https://xdevs.com/article/kx-ref/

My late but effective response to the heat wave

Also OSMU current source / sink clamping simulation: 2018-08-14 11:07:35 +0000 UTC View Post

Unforeseeable result of testing coolant pump on carpet

😑

New OSMU output stage ideas

Sorry for the lack of activity here, this thing is keeping me terribly busy *_*

OSMU introduction if you haven't seen: https://youtu.be/H-BiphMqp5g?t=267

Previous attempt https://imgur.com/epvoqIG had a lot of problems. Comment if you can spot any :)

...

Eleksmaker upgrades ep3 ??

What could possibly go wrong?

Long unedited video about a drill press

Also runout: https://www.youtube.com/watch?v=TfPCK3iLku8

I've never waited so long for a BG delivery: Almost 2 months! But then again it probably took a while to develop that intricate cocoon packaging ...

The DC drill press looks jazzy, the power supply feels like a Kinder surprise egg, but actually lives up to its spec for a few minutes. I had expected the LED display to show RPM instead of voltage.&nbs...

Can I embed photos.google.com now?

Been a while since I tried that, surely they have improved that by now ... right?

Another item falsely advertised as defective 😤

https://www.youtube.com/watch?v=h1-2YicAjxs

1700 exposures ... a busy dentist probably does that in a month 🦷 (<-- new tooth emoji for Unicode 11.0)

Time for a skelfie

Got a broken dental x ray machine ... maybe it fits in the old surgical ceiling lamp holder? 

New step attenuator for the spectrum analyzer

Still something wrong tho, there seems to be a huge dc bias voltage in the higher frequency ranges while the 30 MHz cal signal (which I've verified before) doesn't get through.

But we've come so far with this thing, there's probably not much more missing!

Giving away the 6 remaining 'souvenirs'

One for the comment with the most ❤️s and 5 selected by me based on proprietary algorithms  

😈

Run in testing cheap linear rails

The cheapest linear rails are delivered in a pretty horrible state. Especially the new black ones. I've tried ultrasonic cleaning and re-greasing / oiling them to no avail. Still horrible. Now I'd like to see if they get better after some time ...

Saved the best ones for last

All of these products deserve a closer look, but they've been sitting here for way too long, so I thought I'd show them briefly and get back to them when the time is right

Does anyone recognize that 'PCBway jingle'? It used to be played when starting old PC games ...

Glowy Tritium vs. Geiger Müller Tube

I must have had this tritium keychain for a while, because I remember asking our chemistry teacher in school if we could measure it with the geiger counter there. Being the typical German teacher with 0 passion for getting kids involved in science, she refused because it was her lunch break.

Well, now I can do it myself finally. Result: No noticeable radiation through the acrylic tube it is sold in. The bare glass vessel however causes a slightly elevated 'reading'  😁