Posts tagged with diy

dual water rocket launcher

May 21, 2017


Part layout.


Drilling end cap.


Bike valve cut.


Inside end cap.




Dish soap bottle cap. This is taller than a soda bottle cap leaving enough threads for tightening after a 3/4″ gasket is fitted.


Hole for nozzle.


Gardena nozzle.


Threaded body removed.


Placed inside bottle cap.


Base plate.


Leveling feet.


Base assembled.


Launcher on base.


Guide rods added.


Some details worth noting:
– tennis balls on bottles as nosecones to make them front-heavy
– straws on bottles for guided vertical launching
– strings attached with collars on the Gardena connectors for remote triggering
– abort valves for releasing pressure in case something goes wrong
– non-return valve to minimize water in the launcher and also for keeping the bike valve dry
– holes in the base for fixing the launcher on the ground with tent stakes


Photo Booth Paper Dolls

March 28, 2015


Nelly loves paper dolls. Her birthday seemed like a nice opportunity to try out an idea Sara had: making paper dolls out of photos shot on white background. Since Iris was not even 3 months old, we had to keep it small. Nelly insisted on inviting girls only.

To make things more fun and involve the girls in the process I thought to set up the whole thing as a photo booth. This way the girls would essentially take their own pictures instead of having to pose for a grown up. The original idea turned into a 2-in-1 paper-dolls-and-photo-booth project. For an extra push we brought in a basket and filled it with props and accessories from Nelly’s costume drawer. Here’s a brief making-of should you wish to try something similar.

When dealing with kids, safety is a big concern. Therefore, the basic requirement which drove the whole setup was to keep the floor clear: no stands, no tripods, no cables. This was made possible by doing two things. Using the curtain rod as the background support and an Autopole for holding all the gear.


I was lucky able to source a white vinyl roll exactly as wide as the space between two adjacent curtain mounts. A pvc pipe was used as a core for the roll and a couple of A-clamps fixed the roll in place. Gaffer tape kept the bottom part pinned safely.


I was looking for the heavy duty Autopole (and would strongly suggest you do too), but the only available rental one at the time was a smaller diameter model. This extra limitation meant that extra care should be taken not to overload it and that everything should be kept as close to the pole as possible to prevent torquing forces. Tip: in case you use an Autopole indoors, do your ceiling a favor and protect it from the black rubber feet.


Two pieces of software were used. Both are free apps, but require certain cables to connect.

qDslrDashboard on a tablet showed the girls the pictures they were taking. If shooting RAW, set your camera at RAW+JPG and make the jpeg as tiny as possible (“small” & “basic” in Nikon terms). By doing so you will achieve very fast transfers to the tablet. Use a USB OTG cable to connect the tablet to the camera.

TriggerTrap in sound sensor mode was used on a smartphone. This provided for two things: cable free shooting and lots of screaming fun. Tip: tweak the threshold/sensitivity settings to make the camera ignore the background noise and be triggered only by the shoots/claps/cheeses that mean to trigger it. A delay between triggers will also ensure that your flash has enough time to recycle. In case you wish to capture the post-cheese moment instead of the exact cheese moment, TriggerTrap offers such an offset too. The TriggerTrap dongle is required to connect to the camera.

To keep shooting fast (and predictable) the camera was set at manual exposure and manual focus. Tip: determine your desired in-focus area, set the focus accordingly with the help of a DoF calculator and fix the focus ring with gaffer tape to prevent accidental loss of focus.

Due to the small size Autopole, a single speedlight with a small softbox was used as the only light source. It handled pretty well. The small size offered a little light wrap and snappy contrast at the same time. I did experiment with a second speedlight behind the background (outside the window), but even though the white background was rendering nicer, random positioning of the girls would result in softer pictures and flare. I went with one speedlight for simplicity and to eliminate the need for wireless triggers (and the concern for extra batteries). Also once the paper dolls are cut, it does not matter if the outline is not pure white. Subject to background separation is enough.

Tip: speaking of batteries, make sure everything is charged before the event. It would be a pity to stop halfway because your tablet/phone/camera/flash ran out of juice.

Making the actual paper dolls is a simple 3 step process: print, cut, laminate. Few of the shots will be candidates for cutting into dolls, but the whole process can capture some nice spontaneous moments. Here are some random outtakes.









Shoebox Shadow Theater

September 28, 2014





5 Second Sled

May 19, 2013

Components and execution are self-explanatory.

how to make a home sled sledge sleigh with an ikea bag and a pillow




DIY Leather Grips

April 2, 2011

I gave up all efforts in finding a pair of leather grips for Ralph. Finding something simple and discreet was impossible. Everywhere I looked I kept coming across weird shapes or weird seams or weird logos. The only kind of grips I managed to find that exactly fit my “specs” of simple, plain and logoless were the “Elkhide Sewn-on City Bike Grips” by Velo Orange. However, I was not convinced that their width would be enough in my case (and as it proved, it wouldn’t).

So I decided to make my own.

I have to credit Velo Orange for their stitching instructions though, which I followed with great success.

You will need:

– a scrap of leather enough to give you two rectangular pieces of about 15x10cm (you will end up using less. I made mine with two 12x8cm pieces. I sourced the scrap in an upholstery store for next to nothing.)
– a roll of cotton tape
– a ruler (a triangle is even better)
– an exacto knife
– a marker
– a vernier caliper
– an awl
– a cutting surface
– strong thread
– two needles

Begin with loosening the shifters and brake levers and sliding them towards the stem.

IMPORTANT: Do not remove your shifters/levers from the handlebars. Most shifters/levers are mountable from the edge of the handlebars. If you remove them and then start making the grips, sooner or later you will slap yourself on the forehead and have to start over from the beginning.

Place your hands on your handlebars and decide how long you want your grips to be. Measure this distance. Alternatively, measure the length of a pair of grips you own or google around to find the length of a pair of grips you like.

Apply a layer of tape to cover this length minus about 2mm. For instance if you wish your grips to be 12cm long, start applying the tape 11.8mm from the edge of the handlebars. On each round pull at a tight angle to create nice overlaps. This layer will add friction between the leather grips and the handlebars (in order to eliminate slippage) and it will offer extra padding. It will also add a very subtle wave to the leather surface which is a nice touch (and nice to touch).

CRITICAL: Now you need to determine the correct width of the grip. Wrap a small piece of leather (it can be as narrow as 1cm and as short as 7cm) around the tape and measure the total width with the vernier caliper. It was 2.6cm in my case. Multiplying this by pi (3.14) gives you the circumference of the handlebars with both layers of tape and leather. In my case 2.6cm x 3.14 = 8.16cm. I decided to go with a bit less (8cm) since leather will stretch a bit when tightened.

Knowing the length and width of your grips, flip the leather scrap and mark it on its back side.

Cut with the exacto knife.

TIP: The leather has a tendency to pull when being cut. So, cut intermittently. Otherwise you might not get a straight line. I also thought to use a rolling pizza cutter, but mine did not work. If yours is sharper than the ikea variety, you may give it a try. First, make sure to test it on a small part you are not going to use.

Draw a parallel line about 5mm from the edge of the long side. Repeat for the other long side. On these lines mark the 5mm point and then mark every 10mm. E.g. for a 12cm long grip, mark the 0.5cm , 1.5cm, 2.5cm, …, 11.5cm points.

Using an awl or another sharp pointy tool (a fork with all tips bent but one, maybe?) punch holes on the marks.

TIP: Slightly widening the wholes from the front side will make stitching easier.

Flip your handlebars upside down (unless you want the stitches to be on top!).

Cut a long piece of thread and pass a needle through each side.

TIP: Make sure you have plenty of thread when you start. Better having excess thread in the end, rather than realizing it is not enough when you are halfway through. I used a 2m long thread for each grip!

I started stitching from the bar end rather than the stem end (which is mentioned in the VO instructions), because it made more sense to me. If I had started from the stem end and eventually the grip needed to move, say by 1mm in or out, I doubt it would have been possible after all the tightening (considering the friction of the tape layer).

Find the middle of the thread and pass each needle from the top through the first hole on each side. Then pass each needle from underneath through the first hole of the opposite side . You have the first stitch in place (a parallel one) and you are ready to go.

TIP: If a side of the leather shifts upwards, correct with your thumbs.

diy leather grips

Repeat the following till you reach the last pair of holes: Pass the first needle from the top to the first available hole on the other side (this is a diagonal move) and then exit from underneath the hole across (this is a perpendicular move). Do the symmetrical move with the second needle. Tighten after both needles have moved by one hole.

Keep working with one needle at a time. X-es will be forming along the way.

diy leather grips

When you reach the end, pass each needle from the top into the last hole on the other side, so that they exit under the leather. Use the two strands to make a knot, cut off the excess thread and tuck the knot under the leather.

diy leather grips

To finish it off, apply some leather proofing (the same you use for your saddle).

That’s it! Flip the handlebars, move the shifters/levers to their original position, tighten, done!