Introducing: Sjors!

Sjors van OsSince last week, Sjors van Os has been doing his internship for Industrial Design Engineering at my studio. During his internship, he will regularly blog about the things he’s building and what he’s learned. Since it’s been very quiet on the blog, I hope he will bring some nice stories 🙂 He’s currently building a setup which uses a Wiimote to control a camera pan-tilt-system.

TI EasyScale protocol Arduino hack

Today, I worked on getting the TPS61160 boost LED-driver from Texas Instruments to work. This tiny chip allows you to drive up to 8 LED’s in series from a single LiPo cell. It allows dimming through PWM, but also understands a proprietary protocol called EasyScale. Since there was no example code online anywhere, I decided to hack this together from the datasheet. Since someone else might be interested in this as well, here is the code:


Common Math Equations for Science and Engineering

Once in a while you run into a problem that needs a little math. Today I was working on interpreting a signal from a proprietary interface board, which sends out a pulse, of which the length depended on “x”. However, the relation of x and the pulse length was not linear. It looked like a logarithmical relation, or was it something else?
I Google’d “common math equations”, “math curves” etc. but nothing turned up. What I was looking for, was something like this:

Screen shot 2013-12-11 at 13.13.36

So I decided to make it and share it with the rest of the world. I hereby release it under a Creative Commons BY-NC-SA license. Feel free to remix!

Download as PDF

Subsidies 2010 in Excel-sheet

Altijd al eens willen weten wie er allemaal subsidie krijgen en hoeveel? Iemand anders heeft verschillende WOB-verzoeken aan de rijksoverheid gestuurd voor een overzicht van de toegekende subsidies, per ontvanger en per subsidieregeling. Natuurlijk krijg je zo’n lijst niet netjes aangeleverd; het is een platgeslagen PDF van bijna 500(!) pagina’s waar je niets mee kan. Om een beetje onderzoek mogelijk te maken (Zoek je een baan? Deze bedrijven en instellingen hebben het geld 😛 Zoek je fraudeurs? Gewoon nieuwsgierig?) hierbij een machine-readable versie van het document als Excel-sheet of CSV.



Wellicht dat ik hier ooit nog een mooie visualisatie of datamining-tool van maak. In de tussentijd: happy mining!

Screen shot 2013-12-03 at 12.56.20

$800 Chinese eBay-laser cutter still working!

Below is an e-mail conversation that I though might be interesting for other people as well 🙂

Hey Michael,

Holy shit. Since 2011? Time moves fast! Other than the problems outlined in the blogposts, I’ve been surprised by the little machine. YMMV 😉
No mayor break-downs, however I have noticed a lower laser power lately (can still cut through PMMA and wood with quite some speed though), and I’ve changed the control to LAOS-laser, which has really simplified my workflow. In stead of having:
– Illustrator (mac)
– Corel draw (win)
– Moshi draw (win, cannot be virtual machine)

I now have:
– Illustrator (mac)
– Visicut (mac)

… and am able to do engraving (with quite some resolution) and cutting in one go. So that’s a nice upgrade.

Also be advised that the machine comes with a really crappy exhaust fan which burned out after an hour with me. Since most cutting operations create quite some fumes, you’ll want to have a powerful suction system before you start using the system for production. Also these machines come without a usable water cooling system, air assist and cutting bed/surface. So you’ll have to tinker something for this as well.

Bottom line: I’ve worked with lasers worth 10-20x this machine (Epilog 24, some other German brands) which also had problems. The results (parts) are the same. The original tube, lenses, mirrors, control, motors and mechanics are still going strong. Between my mill, 3D-printer and the laser, this is the machine I use most often, by far. Very little start-up time, no trouble fixing your workpiece etc.
As for bang/buck this is awesome, but only if you have some experience with electrical engineering / laser cutting / mechanical design / laser safety etc. If you don’t feel comfy around a machine that just keeps going when you open the door and stick in your hands, don’t go with this 🙂

Best regards,

Gregor van Egdom
On 8 nov 2013, at 17:04, Michael Martinez wrote:

Hey! Hello, Hola! You are fast!

I really want a laser cutter, but the brand name ones are out of my price range. I’ve been looking at the Chinese versions on Ebay for months, but I am leery of spending $800 on a broken box.

I read your blog, and saw that you had one since 2011. Does it still work? have you had any major problems?

I appreciate your time!



Update 16-4-2018: I came across this software that might be interesting for people running the normal hardware:

And yes, it’s still working!

Solidworks instant PDF, STL, DXF macro’s

Screen shot 2013-09-20 at 11.13.37 Screen shot 2013-09-20 at 11.12.33

These macro’s save a PDF, DXF or AI version of a drawing or STL of a model with the name of the model, in the model folder. Saves tons of time making packages of technical drawings. One-click file-saving! Can be easily changed to save other formats (STEP, IGES, …)
Warning: automatically overwrites existing files!

Download the ZIP package! (33k)

Update 1-2-2016: Since I’m still getting a ton of traffic on this post; I recently tested them with SolidWorks 2016 and they work perfectly.