Raspberry Pi

Raspberry Pi & BitTorrentSync for dummies like me

By | Computers, Platform | No Comments

I finally found time to do something worth with my Raspberry Pi.

I had already installed BitTorrentSync in  a couple of computers. BitTorrentSync allows you to synchronize folders between all your devices like Dropbox, but the data are not stored in the cloud. If you have concerns about privacy, this is the definite tool.

But be aware, unless you synchronize with a remote PC you are fully exposed to data loss due to a fire at home.

The great thing about Raspberry is that power consumption is low to be able to have it always on, so all your devices can synchronize immediately with your Raspberry HDD. You don’t have to wait anymore for the two PCs to be on at the same time, for example.

Raspberry Pi

Well, let’s do a step by step walkthrough over the process I used to install it, for dummies like me.

First the sources. I took all knowledge from the following articles where more details can be found, though not repeating again:


How to add the HDD

Generally Raspberry autodetects HDDs. For better performance it is recommended to format the disc to EXT4.

First find how your disk appears with this command

df -h

It is usually /dev/sda1. With the mount command you can also retrieve the list of mounted units.

Now you will have to format the disk, replace “sda1” by yours:

sudo mkfs.ext4 /dev/sda1 -L untitled

“untitled” is the disk label, in my case I don’t care. If you have problems when you run it try to first umount (check below).
If you have to mount the disk you will need to create a folder where to mount it. We will call it “mydisk” in the example.
sudo mkdir /mnt/mydisk

Then you can mount the disk
sudo mount /dev/sda1 /mnt/mydisk

And now you can use /mnt/mydisk as an additional drive. Create folders, copy files, etc.
If you have to shutdown the Raspberry it is recommended to unmount the unit

sudo umount /dev/sda1

If you have a NTFS disk and you don’t want to format it because you have data already, there is an option described in the first link of the list. But it makes sense to have a disk fully dedicated to the Raspberry, so format it in EXT4!

You will also want that the disk gets mounted in the folder every time you reboot, you can do it by registering it in /etc/fstab. Let’s edit it to add our unit.

sudo nano /etc/fstab

In our case we only have to add a line in the end (use tabs in between)
/dev/sda1 /mnt/mydisc ext4 defaults 0 0

If after this you apply sudo mount -a you will mount all the units referred in the file /etc/fstab.

Now we have a disk,

Let’s go for BitTorrentSync

To install it you need to download the ARM version with these commands

mkdir ~/.btsync && cd ~/.btsync
tar -xfv btsync_arm.tar.gz

And now you only need to run the app
cd ~/.btsync
sudo ./btsync # can be killed with `sudo killall btsync`

You should get a message BitTorrentSync forked and a pid. Everything ok.

And now you only need to add the folders to synchronize. Open your browser in the IP address of your Raspberry and port 8888.


You will see an option to synchronize folders. Choose anything you want within /mnt/mydisk
If you already have a secret form another computer, paste it here, if not just generate a secret and keep it. You will have to add it in the computer you want to synchronize with.
All set. You can create several folders and synchronize them, independently and in addition you can decide which devices synchronize with which folders. Up to you!

I missed one step, how to modify the config to have the program run at boot. There is an explanation in the fourth link.

I hope this has been useful, if not you always have the links I posted for more details.

Titanic Gym

UX in traditional businesses

By | Platform, Thoughts | No Comments
Titanic Gym

The first class gymnasium and the only one onboard Titanic

I am a member of a chain of gyms in Barcelona.

And I am seeing how the User Experience is decreasing from time to time through a strategy in search of revenues not very well defined, and of course looking for cost reductions but in elements that are too visible for clients.

We talk a lot about UX in websites, but it is also important in traditional businesses. The fact is that for a website it is relatively easy to know the impact of changes in user experience. You have a full set of metrics and you can do A/B tests to know what works ans what not.

In brick & mortar, it is more blind direction, except for the direct feedback from customers if you are willing to listen to it.

In case of gyms they are lucky that there is a lot more friction for a provider change and there is some room for clients tolerance when something goes worse.


Some examples of changes that I consider a mistake.

Use the same premises to provide low cost service

This implies there are people that do not have access to some services and then you need to build barriers inside: vending machines for towels, oblige the client to identity identification with a card or a bracelet to get access to any of the normal services anywhere inside the gym (classes, towels, locker rooms, ..). Uncomfortable…

It would make more sense to open low cost centers, but in this case there is additional investment need, of course.

Reduce costs in elements that are really visible

In example to change towels to something that looks more like a napkin. There is clear dissatisfaction from clients.

The trick is that in the Internet you just jump to another website that keeps delivering the service you are used to when something gets worse in the current one. But in this case it is a small decrease in service that the client will finally accept.

My big doubt is, looking at the claims unattended,  how much you can decrease the service level perception to get the clients change directly to another provider even with the burden that comes with it.

Any experience worth sharing in brick & mortar UX?


My new project

By | 3D Printing, maker, Platform, Startup | No Comments


I see now that I have not been writing for more than a month. But in fact this is not exactly true, since I’ve been writing but in the Fabshub blog.
This is the new project that I started with Esteban around five weeks ago.

What is Fabshub?

Basically, and based on the comments from people in several events from the 3d Print Barcelona group, we found that on hand there were people with willingness to 3dprint for others and on the other hand there were people with interest to 3dprint objects. so it made sense to create a marketplace.

In addition, as in our souls we are makers and we love the Maker world we also decided to include other digital fabrication tools such as laser cutters, CNC routers, vinyl cutters and 3D scanners. Those that need something to be made will not have to do it piece by piece. Everything will be available on the same site 🙂

If you need someone to make a design for you we will also have designers providing 3D modelling service.


What have we done up to now?

Well, defining the model, create a landing page, a blog, social networks presence (Facebook, Google+, Twitter, Pinterest), …don’t underestimate the amount of effort that all this represents.

With the first 50 registered users we ran a survey some days ago already. If you want to help you can take the survey here. It’s only six questions. Superfast!

And few days ago we ended the web design, the wireframes. Frankly speaking, the most tedious part. Although we know this will change over time, we need to start with something.

It’s like when you have a plan. Plans are never accomplished on time, but at list they serve as a guide haha.

We are already taking orders via a form. Good practice since it lets us understand a bit what people are looking for, and the fact is that the majority have a maker focus. It forced as to take a service discoverer role using our contacts network: a CNC cut, a 3D scan, a 3d print but with a resin printer, and finally a normal object 3D printing…

Talking to people we also learned about other interest topics such as selling parts, additional services for makers like design and printing of PCBs, training courses, workshops to build 3d printers, …etc…

But this is for later. First thig is to have the basic service up and running 🙂

To finish

If you have interest to know or you want to provide any of the services described I encourage you to sign-up in our website

If you want to request services you can do it already!! just push the Request button and ask…

Corcho en Customizer

I love Customizer

By | 3D Printing, Platform | No Comments

After I uploaded my object to Thingiverse, the cork for oil container, as I explain in my last post it was time to try Customizer.

I love Customizer!!

The truth is it is really simple. Thought to be used with OpenSCAD and some additional libraries.

Once you upload an object in Thingiverse you have to add the tag “customizer” and the app does the rest. When you visit the object you already have the option “Open in Customizer” active.

Customizer interprets OpenSCAD code and is capable to determine the input parameters. You have to follow basic conventions as explained here.

All variables are considered parameters by default, except for those that have an operation or a reference to another variable.

For example, if I want to use $fn=100; to have the cylinder built with a good number of fragments and show it round, this is going to be considered a parameter.

But if I use $fn=100*1; this is not considered anymore.

For my cork model it has taken just a minute to make it customizable.

I added the description to each parameter just by including a comment in the line above, and that’s all.

The result can be seen in this new thing. And the example of options available when you open it.

In the example here I modified the radius to make a more “spectacular” cork 😛

Corcho en Customizer

Cork in Customizer

Tapon aceitera

Playing with OpenSCAD

By | 3D Printing, maker, Platform | No Comments

After short time playing with OpenSCAD I have to say I am amazed since I tried it.

I gues this is due to the concept of programming objects through a script, ans in addition this reminds me a lot stuf I did with POV (Persistence of Vision Raytracer) back in the early 90s.

This week I made a simple object, but practical.


Los tapones

The corks

The cork of my oil container (a very typical shape in Catalonia, see below) is broken and I need a replacement. Why not in PLA?

And by the way, I can do it with improvements.

So caliper at hand and let’s work to get measurements.





In OpenSCAD this is a simple cylinder. You can specify the size of both cylinder faces so make elements with angle, at the limit you can make a cone.


cylinder(h=10,r1=5, r2=0, center=true);

(code for a cone)

Tapon aceitera


Then comes when you make things more complicated.. .time for an upgrade. The upgrade of a cork is just adding a hole that lets the air in and the oil leak with continuity.

This is just another small cylinder and by difference with the bigger one you obtain the hole.

Next teak comes in the hole positioning. I did not want it in the center but in the side and with the same angle of the cork. Easy and quick, just trial and error modifying the angle parameter until you get it right.

But as i had the intention to upload the object to Thingiverse, I wanted to leave it with input parameters.

And this means the angle and position of the hole needs to be formula calculated.



Well, here google is our friend as always to refresh memory of maths quite buried in my brain. Finally, arctan is what I need.


With the translation of the hole in the cork face I have to do something similar to ensure it stays near the edge according to the input measurements.


Final result:

radius1=29/2; //larger width radius
radius2=24.5/2; //shorter width radius
height=21.4; // height

angle=atan((radius1-radius2)/height);//angle for the air hole
   cylinder(h=height,r1=radius1, r2=radius2, center=true);
   translate([0,(radius1+radius2)/2-3,0])rotate([angle,0,0])cylinder(h=height+10,r=1, center=true);
La aceitera y el tapón tuneado

The oil container and the upgraded cork

You can find it here in Thingiverse.

To finish, I still need to modify the code to be able to use Customizer.

If you don’t know it it is worth having a look, really recommended. By following defined rules Customizer is able to identify the input parameters for an OpenSCAD object, and the values range for each one. So any user, with no knowledge at all of the program, can modify the object in the Thingiverseweb to suit his own needs based on the parameters defined by the designer. After that it generates the STL file for you.

I printed in PLA. It is not ideal but I read that it is better than ABS if in contact with food.


3d printing for others – first experiencies

By | 3D Printing, Platform | No Comments

I alreday have my first experiencies by 3d printing for others.

If you need to print something, you can contact me on the menu page “Do I 3d print anything for you?“.

The first request was jewelry printing. Already served.

Marisol makes her own designs with Autocad. And it seems sh has some success around her family and friends.

In fact the pieces gave me  hard time, because they were objects of 2 mm height maximum, with relief and plenty of jumps.


The first prints in PLA had plenty of threads and I had to play with the retract setup to reduce the effect of leaking plastic from the hotend while he moves from one side to the other. There are several parameters related to retract, one of them is the distance that the extruder has to make the plastic move when travelling,a nd of course the speed of the travel.

I also made ABS printings, to check the difference.

If you like her designs you can contact Marisol at marisol_rovira [at] yahoo [dot] es

First tests in PLA. If you look at original size you can see the threads.



Here the whole pack that I printed.

This was the only delivery that I made. And I have three additional requests ongoing.






Truth is, none of them is just print and go. all requests are very thin, in the limit or over it.

  • the pole to hold the catenary on train miniatures. I am working on it, I printed in ABS but it is too thin and when I checked its strength it just broke in my hands. Then I tried with PLA, known to b stronger than ABS. But it seems still fragile for the forces it needs to hold coming from the catenary. They respect sizes at perfection and electricity has to go through the catenary, and no way to change the 3d model. As Miquel came to our printer party I gave him the two tests for free so he could check this out with his father, the real pro on miniatures. But we both left convinced that it was not going to work.
  • a copy of Assassins’ Creed Hidden Blade. Amazing!! the person who asked me is currently working out the 3d model. There are more than 10 pieces to assemble and the whole thing i very thin so I expect hard work again. Nut well, when he finishes the design of any piece we can try. The good thing. He plans to share the model in Thingiverse once finished.
  • an objected with nested elements. The mesh had some sphere nodes net in spherical form, and two spheres around with holes on it. First problem was that the walls were not solid (width = 0) and the second is that the pieces were floating so you need supports and see what happens. I will not be bored!


The catenary pole, in ABS

I will keep doing tests.

But if I don’t receive easier models, like a GoPro support that is upload and print -a no brainer-, this short experience let’s me validate what RepRapBCN people already told me: the price people are willing to accept does not compensate the hours you have to put in there. You have to count the full management of a request: manage the contact, verify the model, generate gcode, heat the printer and print, deliver. You cannot make a living with this. However, there are bets for this model such as and e should see how this evolves.

In these websites that want to build hubs of printers the prices go to the minimum that the website has established, around $0.25 a 0.50/cm3. No business. My understanding is that there are currently several printers with excess of capacity and the owners want to get some cash to reduce their investment…but too much offer for little demand. In fact in Barcelona there is even no offer, and the demand probably does not know where to go.

I believe there is no business model, only to get a bit of extra cash. In fact i think 3d printing is not generating value added. It will end up as the photocopy shops in the past, when only price counted as any other commodity.

And then, where is the valuer? but it’s still not clear. Private printing is still too young. For now the business is to sell printers. New models appear.

You also have groups like shapeways growing 100% every six months or i.materialise. Both do research on new materials and so are providing value to the customer. Customer is willing to pay more for jewels & decoration, especially if you have materials such as metal, silver and gold.

And for now the sector is growing 25% yearly, so these ones will continue growing.

Where I see a value proposition is in CAD design. When we flood the market with 3d printers, if it ever happens, someone will have to feed them with 3d models to print.

Another business model. There are few websites that want to put in contact designers with clients, and meanwhile facilitate 3d printing so that they close the full cycle.

Also thinking about collaboration with designers (Etsy version for 3d) Shapeways let designers create their own shop in their website and their business is focused on printing, with a low commission to the designer.

We are just at the beginning. Many ideas will be tried, some of them will succeed and other swill fail. Let’s see what happens!

como confiar en los proyectos en Kickstarter

How to trust Kickstarter projects?

By | Platform, Reputation | No Comments

After some discussions in the sharing of reputation scores across platforms, it was time to speak about how to trust  Kickstarter projects (and any other crowdfunding platforms). Which is mainly about how the trust mechanisms work there.

como confiar en los proyectos en Kickstarter

I already backed several projects with positive and not than positive outcomes. Truth is Kickstarter takes only responsibility on the funding process. Once the funding process finishes, and the project gets 100% funded, the fundings are transferred to the project and Kickstarter disappears. Well, it still provides the platform to let project team communicate with their backers but no more involvement.

So what happens if nothing is delivered? sorry, but nothing happens.

I was not aware of any big failure, we are more used to hear about big overfunded projects, but googling a bit there are some.

In fact, a study performed by Ethan R. Mollick from Wharton School of Business states that around 3,5% of projects fail (seems pretty low and successful to me) and that over 75% fail to deliver on time.

There was some discussion around September 2012 about this topic, and this article provides an example of a project that failed to deliver and, well, check the backers angry comments on your own here.

The point is that Kickstarter is not a store. Ultimate objective is to let people take risks to build or create something impossible, so of course, failure is a possible outcome and backers need to accept this. You are not buying products.

Kickstarter has made efforts to improve and clarify by introducing some changes and additional guidelines to project presentations. You can check their blog articles about the topic here:

You don’t buy products, ok, but how to assess likelihood of achievement?

Ok, we know we take the risk, but then the issue is how much likely this project is to be completed? could it be a scam?

I see several topics to take into account to help you trust Kickstarter projects:

  • Background of team members. Kickstarter forces this to appear for technology projects. Anyway, you can google the people, look for their studies and current work in the different networks, check their blogs, contributions, etc.
  • Read all the project content in detail. Projects can present their current level of accomplishment. Prototypes, plans, etc…there can also be some former experiences or products that they can show. As one of the improvements, Kickstarter avoided to include renderings and photorealistic pictures of final product to avoid backers to get confused. There is also a risk and challenges section to provide.
  • Google what is being said about the project. You can find additional information from people or newspapers you trust.
  • Check the reputation tools we have seen in previous posts. This one has the most complete list. If they are people engaged with long track record online it is difficult that this is a fake identity.
  • Former good experiences. For example if Eric Migicovsky from Pebble launches another project I will definitely rely on his ability to succeed. For this, Kickstarter will need to include another state to projects to show if they delivered or not (decided by backers?) plus a change to link the list of projects one person or entity participated in. We will need more time to get something here as projects are created and there is some track record generated.

This is nice to do but requires some time, and depending on the amount you will not even consider going through all this. The fact is that I backed Pebble and I was expecting a product in return (although I understand the delays). I did not check that much before funding. There was already a hype about it and learnt from blogs I follow.


Kickstarter, and other crowdfunding platforms, could also apply what is already being used in other marketplaces to provide more trust: karma scores, badges, comments & feedback from backers.

But in addition there are some platform specific indicators that can help: number of projects (open and completed), responsiveness (something special for this platform…how often the team provides updates to backers).

Any other ideas to check  a project? please add in comments.