Create a video lamp

I’m doing quite a lot of video conferences from home and I’ve decided to improve my setup, to have better quality, and ideally, at some point, be able to use it for some Youtube tutorials. I still somehow naively think I’ll eventually find some time to do that…

Anyway, as I’ve discovered recently and explained in my last post, it happens my light setup is sub-optimal. I’ve looked at theory and at option for buying lamps, but I couldn’t found anything satisfying. My main reproaches were:

  • boo bulky, too professional: I don’t have much space and I definitely don’t want to have stands (or drill too many holes in my walls)
  • awfully expensive: I’m not ready to invest several hundreds of francs/dollars in this topic, and this seems to be the starting price
  • disputable quality: I found some cheap solutions for filming with DSLR in China, but they require batteries to run. This is not eco-friendly (I got 230V at home) and the few which had technical specs were indicating currents in volts… Too shady for me.

I happened to have a 30W LED R7s lamp that I bought to replace an halogen and we ended up not using, because it was not enough brights nor dimmable.

Time to hit the workshop and make stuff happen. I scavenged the cable from a broken lamp that was lying around and as usual, got some wood tiles from my trusted IKEA RUNNEN stash. Here is a quick run of the project. As usual, pictures can be seen in original size by clicking them.

As a quick note, I used very little hardware:

  • oscillating tool (FEIN-like) for cutting
  • power drill for drilling / screwing
  • soldering station
  • hot glue gun

First step is to build the lamp holder: cut a tile in 2, drill a 10mm hole, affix to the other with screws. A nail is used on each side to hold the bulb in place and ensure connectivity

Bulb is held in place by 2 10mm holes in the horizontal tabs and a nail on each side
Back plate holds the 2 tabs with glue and 2 screws
Detail on the back and other side

Next step is to connect the wires to the nails. Some simple soldering: put soldering on the wire, bend in place, then solder to the nail. Surprisingly, the nail had no issue properly holding the solder. Then, isolate with tape and cut to have it look cleaner.

Solder the wire to the nail
Hide the metal under isolating tape
and cut the tape to have a cleaner finish

Next step is to affix diffusers, to have a nice and smooth light. The power supply wire is held in place with a nail and hot glue. I cut pieces of disks from mdf (the back of an old billy shelf) then nailed them on top and bottom. One of them had to have a small hole for the cable and I broke one of my small file 🙁 Next time, I’ll pull the dremel. I used cooking paper (sulfur paper) as diffuser: I’m a bit scared about the fire hazard and I want to make sure it doesn’t produce too much heat. The diffusing paper is held in place by the engineer best friend, tape. This will have to be reworked.

the 2 diffusers holders in place
Diffuser in place

The lamp is held in place with 2 powerful magnets (1cmx1cmx1cm neodymium), on the chassis of my desk

Detail on magnets holding the lamp. it connects to the screws heads.
Lamp in place and working

Lessons learnt:

  • I need a second lamp for testing, this is so powerful, this completely breaks the balance of my setup
  • Baking paper is very brittle and super hard to work with
  • Hot glue is evil, each time I’m using it, it’s worse. But it pulls me. So evil.
  • Lamp is too powerful, I should use a stronger diffuser, further away (bigger disks). Maybe a simple piece of white paper will do
  • Some solder drop on my pant, I now have a hole :-/
  • Simple projects like that are better done by trying in the workshop rather than trying to do plan, I actually tried and failed a 3D model on wednesday evening to do with the laser cutter. The result would have been nicer and more reproductible, but I had way more fun prototyping 🙂
  • The heat is under control, less scary than expected


Overall, this is worsening my current setup but I’m pretty happy. This was a quick hack (2.5 hours end-to-end) and this worked as expected, with very little to update. I’ll definitely order a new bulb and build a second lamp.

From better video to better still pictures

Earlier today, I was in a meeting and I was thinking how to improve the quality of my video conference that I often do from home. I was at the time especially focussed on how to improve the sound quality. After some Nerd Sniping from my boss, I ended up reading about some internal document that basically describe the following steps:

  • get a decent webcam: done
  • get some proper lighting: I thought it was ok for my home setup, but some tests proved I need some improvement. More later.
  • get a good microphone: well, this is 3rd step and I got sidetracked

About the lighting, the theory explains that you need 3 lights. I’m not an expert so I’ll just link the video I just watched on the topic and that sums up the totality of my knowledge:

My current lighting strategy involves 2 IKEA LED lights (they seem to be named JANSJÖ) that I use as indirect light, hitting a white paper and on my right and a wall. I don’t have a hair light but I have a GU10 spotlight that I can redirect so I’ll focus on this later. As I discovered this lightning is far from being powerful enough, I scrambled and found some other LED lights we used when the kids were babies. They seem to be named DIODER but we have only 3 heads remaining. Each head has 6 LED and some more basic tests showed they were providing correct power at roughly 1/3 of the distance I could use them. As amortization is quadratic, it happens I need something like 54 LEDs to have proper lighting. As 48 LEDs seems to be a good standard, I’ll probably buy 2 sets in the near future, when I find them at an agreeable price (read cheap knock off from aliexpress).

Anyway, I was back to square 1: my video conference did not improve but I now had spare lights (and some stuff in my office). Then, it hit me: I had issue taking picture in the evening when I did my last laser-cutter build (free teaser: it’s a gopro box and you can find all the glory details in the relevant post). So, I got my hot glue gun, some cardboard (it happens that a empty litter package was available) and started to build.

The build is pretty straightforward: Cutting, hot-glueing, double-side tape. It’s called an ugly prototype :-). Some pictures of the process (just click to enlarge).

Glue the sides
Adapt the roof
Add the lights
Professional shooting set!
go pro box
laser-cut cube

After 2 hours, it’s time for a small conclusion:

  • To have enough Depth of Field when shooting macro, you need to close like crazy (technical term). These pictures are typically f/25 and 10s exposure
  • When using 10s exposure in a flat, you don’t move. And you don’t breathe. Actually, you even hold the cat to prevent vibrations.
  • Your best friend when shooting long-ish exposure on the fly (i.e. holding your camera and shooting 1/8th) is your worst enemy here: disable Image stabilization and the pictures are going to be sharper.
  • Don’t press the button: use a remote or the timer from the camera and walk back as far as you can
  • This is studio time, pick your lens carefully. You don’t care about aperture, you care about piqué  (or whatever it’s called in English, optical sharpness?)
  • Shooting macro will actually give you 24MPixels to look at your stuff. Most of the pictures didn’t make it just because I was ashamed of them (my wedding ring is actually disgusting when I look at it from close)

Anyway, my video conference setup did not improve (yet) but I’m researching about microphones, so expect more on the topic soon.

Building a microscope


I recently bought on aliexpress a powerful (and cheap) microscope. For 15 bucks however, the feature set is quite limited and it has no autofocus, meaning the body needs to be moved to put things in focus. As the official support has 2 ball joints, it’s almost impossible to be accurate : when moving focus, you end up moving the sample and must restart. On top of this, it’s almost impossible to do any kind of fine tuning and the microscope has very low depth of field, requiring displacement in 10th of mm for focus.

I decided that building a body where I can accurately change focus would be my October monthly hack. It was completed in October and was super late for posting… Let’s call it a Novctober hack.


As usual, I’ll be using a share laser-cutter and 3mm thick mdf. The laser cutter is free for use at work and mdf is the cheapest material you can find for hacking around.

My idea is to lock the body of the microscope into 2 rings and use a carriage that can slide on vertical rails. Actual movement will be done using a threaded rod. Looking at my stash of junk, I’ve seen that I have a 1m long M6 rod. I also happen to have a set of M6 nut from a previous project that I can easily embed. To avoid putting too many constraint on carriage, a single nut will be used to do the translation, from the bottom.

For reference, this means that:

  • the hole must be 6mm diameter
  • the equivalent nut is an hexagon, 10mm flat to flat
  • the thread is 1mm per rotation

Open questions:

  • The amount of space needed for the carriage to properly slide is quite unknown to me. As the mdf is actually slighrly thinner than 3mm, I’m going for 3mm and no margin, and will sand/grind the relevant pieces if required.
  • not sure the amount of force (torque) required on thread to move the carriage and device. Assuming I won’t need additional torque and can directly turn the raw rod with finger. Some lubrification might be needed at some point

First prototype

The first prototype proved it was a viable concept, it however showed some limitations.For reference, it’s based on v10 of the fusion 360 file

  • the amount the carriage can travel is too small, the body needs to be much bigger
  • the lack of back plate means the body was not sturdy enough and could shake / shift (parallelogram disortion)
  • the holding ring are not compelled to stay horizontal, need to add orthogonal pieces
  • Having a removable support for sample would be nice
  • One of the component was badly extruded and lacked a hole

What confirmed worked well:

  • the carriage slides without issue
  • the hole is the correct size
  • the overall concept works

Second prototype

Rework is implemented in v14 of fusion 360 model, the actual printing can be found in this commit on the usual bitbucket repository, in this file. The print uses roughly an A4-sized sheet of mdf, all included.

img_20161014_140214 img_20161014_140325 img_20161011_145901

After building, quick summary:

  • despite having longer range of motion, still unable to focus at lower zoom, would need several more centimeters
  • the back plate has 2 holes which are not the same side, forgot a constraint in the design (just an aesthetic issue)
  • the carriage works fine with the redesigned model, the nut needs to be glued though because it’s not heavy enough to go down with gravity
  • while glueing the sliding bar, I pressed them too much and the carriage could not slide any more. had to sand quite a bit of material to make it work
  • the holding tray worked well

Reference for assembling

I decided to sand all pieces, to give a smoother feeling. I sued Grit 600 for starting then finished with Grit 1000.

Pay attention to the following tricks for glueing / assembling:

  • sliding bar needs to stay parallel, don’t over-constraint while glueing
  • to help aligning the 2 bottom plates, use the vertical sliders
  • Don’t glue the full body before inserting the sliding part
  • I used 2 nuts locked against each other to prevent the threaded rod from moving

Some more

After a few minutes of usage, the lighting of the microscope failed probably linked to a deficient solder. Wiggling the cable helped for a while, but I have limited hopes. However, worst case, it’s still possible to use external lighting so it’s still usable.

The device itself exposes as a video device, I could use it from Linux (/dev/video) and Windows (as a directX  input device). The pictures below have been taken using VLC (open capture device in the file menu) then use video/snapshot to get pictures.

Some pictures for reference, overview of a feather from my bird.

 View of the feather, for scale.
This is a standard post-it and a standard sd card
 Minimal zoom, I didn’t have enough distance for focus, so I used the empty bottom of the microscope to actually make it higher  vlcsnap-2016-10-14-15h50m57s657
Some more zoom on the top of the feather vlcsnap-2016-10-14-15h53m00s405
Maximal zoom on the tip of feather, using the removal tray.

The background is wood fiber from mdf, field of depth is super short.


Lessons learnt

  • despite having a full 3D model, 2 iterations were required and it’s not perfect, dynamic mechanics is (unsurprisingly) much hard than static
  • the reliability of a component sourced from China for 15$ is on-par with expectations

Some more pictures

The following pictures are, in this order:

  • a 1 dolalr us bill, zoom on washington’s head
  • the backplate of my phone
  • a mechanical watch
  • the atmega328 on an arduino mini
  • a SMC resistor from an ESP8266



This post and the related original works and pictures are covered by the creative common licence, CC-BY-SA.

Box for GoPro batteries


IMG_2200I recently bought a GoPro and wanted to make a box to store the batteries. To be clear, my model is Hero 4 Silver and is using these (AHDBT-401) batteries. It’s easy to find the electrical properties (3.8V DC, 1160mAh, 4.4Wh), not so easy to find the physical size. Here is a quick overview of the key dimensions I noted:

side size top

Out of this unreadable post-it, the important to remember is

  • the full battery measures 36 x 10.9 x 32.5 (in mm)
  • the bottom part of the battery, where GoPro is written measures 30 x 10.9 x 30 (in mm)

The design will be symmetric, to allow to store the battery facing the lid or the opposite side, to distinguish between full and empty ones. I also decided that 4 spare batteries is a good number.

I usually draw my laser-cut design with inkscape but I decided to follow a different path this time. I recently discovered fusion 360, which is free (as in free beer, not free speech) to use for hobbyist. So, for the first time, I did a full 3D model, that can be found here. You can play with the model online and explode it to see the various components.

This is one of my first parametric 3d design, I learnt quite a lot. It’s then definitely time for a pro vs contra using Fusion360 vs inkscape.

Pro fusion 360 / against inkscape:

  • design is fully parametric, changing thickness of material or size of the battery does not involve to restart the design from scratch. I typically had to move from using an m2.5 to a M3 screw (to match what I had in my inventory)
  • you can use standard parts in your design (I used a M3x12 bolt and nut)
  • You got full mechanical constraints, so you can play with your various pieces and check. I discovered an issue that way (there was not enough place for the nut) and avoided a prototyping iteration
  • There is friendly support on forums and a lot of very well made explaining videos (tutorials) on a youtube channel.
  • There is a CAM module, to do machining with a CNC (not tried yet)
  • the web viewer has support nice features. You can explode the components, select specific components (using design button, top left). Time to check the model again 😉

Pro inkscape / against fusion 360

  • inkscape is open-source, uses a standard format, stores locally. This allows to use version control and have lots of freedom (and is future safe)
  • fusion 360 has a 1-year long license that you can renew, courtesy of autodesk and is storing its data in autodesk cloud. It might stop at any time, locking you out of your own designs or forcing you to pay an (expensive) license
  • inkscape’s use of splines is more common for computer users (rather than bezier)
  • Doing a full 3D model currently takes me ~3x more times than drawing in inkscape. I think on complex design, the reduction in the number of iterations evens this out.

Overall, I’m super glad I tried Fusion 360, it’s quite easy to use and has super nice results. side

About the design itself, I wanted to have a design with a lid and it’s the first time I really have moving components. the trick I used was to deport the axis of rotation on the top-left to make the rotation work.

I used 2 bolts and nuts for the rotation (M3x12). Tightening them is enough to have a lid not opening.As usual, the box is also posted on thingiverse.

For bragging rights, some more pictures:

IMG_2171 IMG_2151 IMG_2206 IMG_2203



Youtube and me, second round

My first try with youtube was such a tremendous success  (ahem) that I had to try again. The main problem of previous video was a really crappy sound. I did lots of tests since and discovered that my headset is producing decent sound quality with audacity. However, if I try to record directly from lightworks or OBS, the sound becomes awfully crappy. I don’t have an explanation yet.

Today’s topic is a response to tripa’s challenge to do a dodecaedron with a straigth edge and a compass. I found it quite interesting as it allowed me to explore other alternatives.

Let’s go to the gory details:

  • Shooting is done using my reflex (Canon EOS 550D) and a 28-55 optic (if I remember correctly).shoot_reflex The setup involved holding the reflex vertically and connecting it to my computer via USB. The challenges were mostly that the optic I used is a zoom and tended to fall and change focal and that the vibrations tended to shake slightly the video. Overall, I’m pretty happy with the video quality
  • Shooting was done with my crazy parrot trying to help. Not sure if she was successful to help but she had a great time.
  • I used lightworks, again, and I’m still not convinced. I was unable to zoom / trim my still pictures in the video editor (hence these nice black band) and export is limited to 720p, which is a pity knowing the initial material is 1080p… Some UI issue killed me as well, I have a feeling  that I’m not in control and it makes me slightly uncomfortable. Especially, I liked the concept of using subclips and reusing them, but I was hoping for references rather than copies : if I make a “introduction” edit and use it in my main edit, it seems like editing the intro one has no effect on the main one….
  • Getting decent light is not trivial either, probably need to work on that one, I played easy as it was dailight and I had natural diffuse light (thanks to the snow falling from the sky)
  • I used some background music that I took from I checked 10 times and it seems to be really fine with what I’m doing, I’m no musician but I found having a soft background sound helped. I definitely should do better with regards to music editing, I feel really crappy (no soft transition, lack of music at some point). I hope it does not cover my voice.
  • I recorded the voice using audacity, then exporting sub-sample and mixing them. Not using face video means not having to care about AV synchro 🙂
  • I inserted a title and some rolling credentials, was surprisingly easy !

My conclusion, it’s not trivial to do but it’s doable if you’re fine with a sub-par result. If you aim at higher quality, then the effort grows exponentially (and so does the headache)


Youtube and me

I’m from a generation who was taught that the ultimate source of knowledge are the books. I managed to evolve on my own and found that internet is a wonderful place where lots of people share lots of interesting stuff. I was pretty happy with that situation : look for a blog post or an instructable, a random tutorial, more or less crappy, follow and tune, troll. I had the manual on how to do it, from newsgroup to phpbb forum. Eh, I even got my own personal blog!

The new generation seems however to have moved out of written knowledge and shit into using video as a solution to any problem. I personnally don’t like too much, I find much easier to skip and follow written instruction than a video whose focus is not always on the interesting part. Anyway, if the moves has moved that way and the cool kids are doing that, I guess I don’t have too many choices : follow and try to be a cool kid (ahem) or start becoming obsolete. I feel too young to be obsolete, so I looked at what is the effort required to create a decent youtube tutorial.

Bear with me: I didn’t want to do a crappy video with my smartphone of me doing something stupid (see : tthat how you plug an sdcard into a raspberry pi while focussing on the cable behind. I wanted to do something nice, not prolfessional but somehow useful.

Conclusion, it’s tough! My personal computer environement is composed of mac (corporate laptop), linux (poor laptop) and windows (gaming rig). It seems obvious that I want cross-platform tools, I got kids and less freetime than the average student, not talking about the random teenager which seems to be the most adept at posting content.

Ok, I tried tonight, spent roughly 3 hours on a simple inkscape tutorial

  • I used Open Broadcaster Software for screencasting and mixing video and sound
  • I used lightworks (free as in free beer, not free speech) for assembling clips together

Lessons learnt:

  • if you want to explain something, better know exactly what you are doing. Especially, first try was a one shot with lots of trials and errors. So shot sequences and mix them later.
  • mounting sequences is hard: it took half the time to just link them together and it seems I managed to export a 30 minutes video while having 10 minutes of content
  • software limitations are bitches: I shoot in 1080p, could only export to 720p, which is a major issue when shooting a screencast.
  • my microphone was saturating, so I reduced gain. And then you can’t hear me (used my heaphones as microphone)
  • had to shoot twice cause I used a bad codec the first time, this pissed me of (we’re in 2015, isn’t the codec mayhem supposed to be fixed?)

Next time:

  • redo the same video, I’m becoming exceedingly efficient at drawing dodecahedrons schematics
  • write a script that you can follow
  • keep empty space before and after each recording, it’s easy to trim
  • read more tutorial on mounting tool, maybe switch to cinelerra?
  • prepare an intro, add titles and copyrights
  • merge some sound as background and control current sound level
  • avoid any kind of copyright infringement

If you want to laugh, here is the result:

Screen/laptop holder


Until recently, main screen was resting on thick book to be slightly higher and end up in front of my eyes. As part of a revamp of my setup, I decided it was time for an upgrade.

I had some specific needs:

  • my screen needed to be roughly 10cm higher than desk
  • I have a 5.1 sound system and a gaming keyboard, I wanted to be able to hide cable aas much as possible.
  • I sometime use my desk for home office and wanted to have a convenient place to plug my corp laptop (mac book air), which includes power supply, USB to a hub and screen connector (for some reason, I have a KVM that doesn’t want to work with my setup, the probable culprit being my keyboard and its >500mA requirement…)

Having the requirements, I headed to inkscape and here is the result, while assembling:


and once installed:


As usual, the design files can be found on bitbucket (I was lazy to put it on thingiverse as it requires lots of material). Design document with all my gory details and cutting document. The numbers identify how many time each piece must be cut, F means Front and B means Back (to help with assembly). As usual, licence is CC-by-SA.

I had to slightly file the edges wto help with assembly, glue everything together and that’s all, no major trap. It needs to be cut out of 3mm thick material (I used plywood but acrylic could work). The laptop holder is 2cm thick, which is ok for a mac book air or a mac book pro.

The things to potentially improve:

  • the vertical layers are a bit weak and bend, adding additional constraints or thicker wood my help
  • holes at the bottom to help routing cables would definitely help (on the horizontal tray)

So far, pretty happy with the result, ready to use it!

Designing gears with inkscape

For a hush hush project, I need to use gears and I plan on designing and laser printing them.


I found this old article which explains a lot on how to make gears with (older) inkscape. It relies on the following technical reference. With new version 0.91, things have been a bit simpler.

Unit can now be express in human readable values (i.e. mm). To make gears compatible, you need to use the same circular pitch – let’s use 5mm.

I want to have a 2x transmission ratio : let’s build a 12 teeth gear and a 24 one. I’ll use a turnion as axis, 8mm central hole is then fine.

Gear Teeth Pitch Diameter
Gear 1 12 teeth*p/pi=12*5/3.1415=19.09
Gear 2 24 teeth*p/pi=24*5/3.1415=38.19
Gear 3 18 teeth*p/pi=18*5/3.1415=28.65

Distance between gears is (Di+Dj)/2

Gear 1 Gear 2 Gear 3
Gear 1 19.09 28.65 23.87
Gear 2 28.65 38.19 33.42
Gear 3 23.87 33.42 28.65



Render the 3 gears using the extension: Gear_plugin

Prepare guides to hold support. Motor gear will be Gear 2, offset 100mm. Keeping some space for security (0.3 mm), secondary gears will be Gear 1, offset 100-28.65-0.3=71 and Gear 3, offset 100+33.42+0.3=133.8. Using an horizontal line and snap on center on bounding box, you should end with something like that.Gear_Create_guide Gear_virtual_assembly

Move the gear parts to a dedicated layer, hide it and start with a fresh one. Use my plugin to create the holding box. You’ll want a holding box whose internals are roughly: 95*46*16 (we’ll be using 3mm thick plywood, 16= 3*5 + 1mm margin)Gear_Cut_box

Duplicate the top and bottom lid, prepare holes (9mm) fot the secondary gearsgear_bottom and front

Control will be done using a sg-90 servo (or a chinese equivalent). Mine require a rectangular hole of 23×12, axis is 6mm from top. Prepare hole and drill it.

Set drawing to 0.1mm red (cutting), 0.1mm blue (engraving, used for center of drill) and coloring to yellow pale, copy everything to a new layer and setup on page:gear_to_cut


I cut the prototypes and have a first round of feedback:

  • It’s working !
  • My drilling indicators are wrongly place (for servo), need to measure better, easy to fix
  • The offset I used to allow cranking (0.3 mm) is too much, as the laser itself as a few 1/10th of mm thickness. 0.1 would have been enough (or even 0)
  • Assembly is non trivial, I need to order additional hands
  • I didn’t fully assemble it so there is no picture (just snapped the pieces together to check)
  • The real version based on this proof of concept worked 🙂

R.I.P Billy

R.I.P Billy, for thou shallt be reborn and never forgotten.

I had an old Billy shelf which was starting to collapse and had the wrong color (moved from one room to another…). It was time to swap for a brand new one (yeah, trip to ikea!!!). The old one got repurposed in my cellar to store my tools.

For those interested:

  • I used 5 horizontal layers of the Billy, 3 vertical to make the back, 2 horizontal, held by EKBY STÖDIS
  • The top of the shelf is reinforced with a vertical part of GORM that was lying around that I cut to size and screw
  • A set of nails was used to hold the tools
  • The shelf itself is hanging using hose clamps (holes are 8mm, inside both the vertical billy and the grolm)
top of the shelf and hose clamp (front)
back (from the public area surrounding my cellar)
finished result

Rainbow loom and hacking

A while ago, I ordered from alibaba (or dealextreme) bazilions of elastic bands for the kids. However, I forgot to buy a loom. Being back from vacation, sunday evening needs an occupation for the kids.

Time for some hacking! I’ve already used the elastics between 2 fingers and the kids are now good with it and ready to move to more complex figures. I had some spare  wood (from doing the terrasse with IKEA Runnen)

First, unscrew the plastic holdings to get some fresh pieces of wood.



Second step, use a mail to help with drilling correctly. You can use this sample drilling plan (hosted on bitbucket, use RAW button to download).

Once all holes have been marked, switch to drilling (I used a 8mm wood bit).

And then use some trunnions (8mm) to make the pin. You might need to convince them in the hole with a hammer.

Once done, the result should look like that.


This allows to have a triangle, a square, an hexagon and 2 pins, each time with a hole in the middle, for various forms.

Probably more, don’t really want to look for more patterns now

IMG_20150628_151032 IMG_20150628_151039 IMG_20150628_151042 IMG_20150628_151053