Acerca de andreas

Is a trained chemist and architect. He got trained at the Treibacher Chemical Factories where he got formed in different laboratories like Reseach & Development , Active Oxigen, Central Analyses etc.. etc... Then after a profound and wide education in chemistry, he was 2 years responsable for the physical laboratory of the Rare Earth Division. Made the school leaving examination at night and moved on to Graz to study chemistry. After two years of chemistry, from one day to another, in a somehow schizophrenic move he decided to become an architect. A decision he never regreted. He studied architecture at the TU GRAZ and at ETSA Sevilla and worked in different national and international architectual studios in Vienna, Sevilla and Barcelona. For 2010 he will get founded with the Nicola Tesla Schoolarship that will take him to Paris. Currently he is living in Barcelona, prepairing to finish his studies in Paris at the École Nationale Supérieure des Beaux-arts.

the tomato roundabout test


So what you can see here in this setup is the version that i tried. The pressureswitch is really really close to sensor ( in height difference ) . That had two reasons. One was that i wanted to increase responsitivity and the other there wasnt’t more space because i had to close the window :). The result is that it is too close. A distance of min. 10 cm from the sensor underside to the switch should be. Otherwise there is no real ” work” done  ( in terms of thermodynamik “work” not that of karl marx  )  and the sensor will not  switch on or off.


They first thing is wanted to change this time is the power supply. The ATX power supply  hack is way too much for one sensor, too loud and too expensive. Too buy a 12 v leiser  batterie that is connected to a solar pannel that recharges the batterie, is too expensive ( ding ding ding ) . So i decided to use old electrodomestic transformers.

Transformers are quite commen. Those are those black boxes that come with everything you buy that needs electricity.The work of the transformer is that is converts the 220 AC into DC and the voltages and ampers whatever is need by the consumer product.  You found them in every flewmarket in all shapes, forms and voltages and amperes.  It could be a nasty task :)

I picked up three different types all of them 12 Volt and amperes from 400 mA to 60mA and payed 2 euros each.  I took a sony which a chinch ending , a langelsbold with a handy plug ??  and a matra with a network plug.

The first one i tested was the sony.  I cut of the plug and there where just 2 wires. The measuring was 18 V. 6 Voltes more then expected( cheap multimeter proberly too ) . I workd well with the 12V waterpump from the windshield cleaner and it worked well with the electrovalve 12 V. In use or standby it gets slightly warm , which means it is not of the newest generation and that it consumes a little standby energie.

The Langenselbold didnt worked? I really dont know why. I  did a short search on google where it comes from and i found nothing. I appearas that langensbold is a town in germany.

The Mantra adapter with the network plug was i big suprise. You can power 2 pumps with on transformer. The foure wires are coloured  black, yellow, green and red and the work in pairs. The output voltage was similar between the 2 possible solutions. Grenn + yellow with 14,5 Volt and black and red with 13,6 Volt. On the  transformer is written that it powers the 11 V with 60 mA. That is significly lower then the Sony , but it worked well with the LED, pumps and electrovalve. So conlusion , just look for the voltages and it should be fine. Reuse old transformers is cheap and good and re:farm . You can power your devices easily with the wanted voltages. The current is stable and safe. With the ATX power hack i alwayes had short circuits and it was annoying to work with.  When you just work in one range of voltage a AC/DC transformer can be the choise to go for to power your selfbuild things in a clean , cheap and save way up.



summercamp at shu lea & maliks house

So after beeing occupied with a lot of other things i can spent some time on the re:farm proyect. A friend and re:farm member left me her flat and to do the watering of here plants. We suggested to use that time usefull and do some humidity sensor testing. The re:farm nano board that includes the new sensor techology will be produced in november. Till that i will try to do it without to get more dates about reactive time and calibration of the system and think about electricity for teh parts.

What i found out at my place is that the reaction time of the sensor is slow and not constat. Slow is not the problem it is even more beautyfull and fits even better to plants . The are not know for beeing the hurry typ of species :)

pressure switch communication

So it definetly works!!!  My depest repect to you Mr. Medici. Your self automated watering sytem is the best low budget automated watering sytem and it beats all comercial products. 10 John Meda simplicity points for your design. I definitely fall in love with it :).

What i have seen is that it took nearly 49 houres for the plant to consume sufficent water and to overcome the hight distance between pressureswitch and ceramic sensor to do the switch.

To do the reverse operation it took nearly 50 min or to be less precise 1 hour. I handwatered the plant with about 400ml of water , directly , no dripping system. Thats the next point about this system. If it is indoor it must be precise , otherwise you water your carpet too. This will be relationated with the tubes-diameter, folds and switches inside the system, the kind of valve and pressureswitch, the waterpressure, the hight of the watertank etc.. But it is not a real problem you can addjust all this parameters with the height of the pressureswitch.

mange bien :)

Till i find out how the wiring is done for the pressure switches i decided to make a little test about the response time of the system. What i want to find out now is,  do that really works at my place with my parts and how much time my plant needs to drink the water from the switch and does it  switches. If this is done I will water the plant by hand and i will see if the process will be reversed and the switch will go back in his OFF state.

The plant is a present from a friend of us and I have no idea what typ it is, but I very happy with it and sometimes when I’m out I give here a place next to the window to enjoy the day. I watered that plant  in summer at here house and it is a very thirsty type. In a previous posting about the ceramic sensor i found out that the plant consumes about 15 ml in 24h. ( proberly, I  didn’t measured they water amount , because i dont have that equipment ).

I filled the switch and the sensor with water , and it is imposible ( with my tubes etc… ) that you dont have air in the system, but i  think that that will not be a problem. So i filled everything. The switch made click. It just takes a little amount of water, my tubes are very small, so i think the system is quite responsive.

I checked they continuity at my ports and they measuring gave me the values:

Filled = switch OFF = pin 21 + 23  =  000 /   pin 21 + 22 = 1

so during the next 24 h they continuity should change if they plant drinks the water from the switch.( yummy )

What I forther  did was to water the plant a little around the sensor. As you can see in the foto the water passed the earth and a little stayed in the groundplate. What I have seen then is that the earth absorbed that water during one hour into the system and that made the bubbles in the tube move down( 2 cm) . So it looks like that he system is really good responsive :). One point more , the switch is 40 cm under the flower pot, that is importend , because the system and the pressure relates to the difference in height from the sensor to the switch.

pressure switches / pressostate

The 2 differnt types i bought and i have no idea how they really work, but with the help of the internet I found out that one of them is  from a dishwasher and not from a washing machine. With a multimeter I made a continuity tests and it looks like that one is having 1 trip points and the other is having 2 trip points.

With the contiuty test you can test the pins how they respond and if the work.  You just have to measure two  pins and them blow into the switch, if the switch works you hear a click from the switch and the continuity will change from 1 to a 3 digit number and vice verce. Those pins will later be connected to the solenoid valve or water pump and send the signal to water our plants :)

Here is small video that explains pressure switches.
youtube pressure switch video

marché aux puces (fleamarket)

In search of the pressure-switches i decided one grey sunday to go the marché aux puces at  Porte de Clignancourt, which is  the bigest fleamarket and the oldest fleamarket  worldwide. It is a marvellous place where 3 times a week you can find from  very antic furniture and aireplanparts  till the latest underground french hip hop bootleg from the banlieu and other curriosities. And you can get there pressure switches. I bought 2 different types and a small motor for test reasons for a very nice price.  It was very nice day out in Paris :)

a new watering system

So piece by piece we are moving forward, I had a another meeting with AAA, this time with Doina the cofounder of AAA and Leonard from Guerilla Gardening – Paris who is doing currently an intership at there office. Doina explaned me that she is definetly interested to make an automatic watering system. Something that we  not proposed, because they are always at there Office. During the conversation we came, with the help of Leonard,  with a lot of different solutions up, but we didn’t convinced ourselfs to a final solution. Leonard showed me a watering system that is commonly used in Paris that i didn’t know before. It works with capillerty of ceramics and is basically the modern version of the ceramic mug in the earth. In Paris I have seen in the balconies plastic bottles standing out of the flowerbeds and I wasn’t really sure what this is all about.  There a several types of that ceramic watering system and you can find them easily by  goolgeling. During my study of that ceramic system I came across a paper by an brazilien agriculture scientist named Leonardo Oliveira Medici. He and his team developed a automatic selfwatering system that uses ceramic water purification capsules as humidity sensors. You can find the whole text here. Since measuring humidity with electric conductivity is not always satisfying I will try to install that system.

AAA allready developed various drip gravity watering systems, so for there future proyects it could be a good and easily to assembly solution and could be used in there backyard.

The foto shows a comercial ceramic watering system that i bought ( 5 Euros) and the consume of water by a single plant at roomtemperatur during 24h.

Polycarbonat & readymades

After the first meetings with Constantine from AAA we could not  come to an conclusion , what is should be.We are generaly concerned about to make the most suitable solution that really fits for the place and its persons. Or too stress Deleuze & Guattari to produce a black hole / white wall effect in the vitrine.  So in the first meeting we could not  find a suitable solution that convinced Constantin to be adequate for there office.   Time passed on and I was chewing on the topic , over and over again. We had the need to  use this 30 cm width for a vertical farm. So the best way I thought should  be to reenforce the allready existing structure. Recycle it.  Till now the plates  of PC are used to hold smaler things, books and papers that are presented to the passengers   that pass by the office. To carry the amount of earth that allows to  grow plants , they are way too weak. To improve the structure I decided to use  measuring sticks and ressemble an traditional construction technic, the trussed beam. The beauty of that proposal is that it is not a citization of an old technic . The readymade solution converts the technic in something new, that stands for something different and in that case for the work of AAA.

storefront & backgarden

In our first meeting, after observing the place which consits of a  interior court with an  vertical garden and a vitrine with a polycarbonat structur for presenation and visual disconnectivity,  we decided to focus primarly on the vitrine. The “garden of tourture” –  we decided to lay that down and preserve that problem for later.( differnet planting etc..) As you can see in the foto, if the plants wouldn’t have rizes , they would have allready moved on.


In Paris , we get to know the Atelier d’Architecture Autogeree (AAA).  A  parisien architecture office that makes a different approach to the practice of contemporay architecture. Visit there page and get involved into the participative approch that AAA brings to architecture and there urban tactics

They kindly offered us there window space and there backgarden too test new things here in Paris.

independend garden 1.0

So finally we finished the hanger prototypes and here ist the final update for me on that project.

Since I’m now liveing in Paris and will do my farming here other things are going to come. Soon there will be a new re:farm blog and much more things . After long delays with the earth the projects didn’t developed very fast, but at the end we finished it quite fast. Which i think is a pitty. One week more and it would had been perfect, but doe to the starting construction on the hanger side we had to move.

What i tried is to copy a ceramic flowerpot.
The ceramic flowerpot is an amazing construction. The material is having a homogenic air circulation over the hole surface on a micro level. So the plant/earth/root/ system can breath.

My copycat flowerpot  is a doble layer system. The inner layer is a organic net that should avoid the earth from falling out. The  second layer is made out of  ceramics that i found at the Hangar-site.
What i want to do is to make the surface of evaporation smaller. The ceramics that we found at Hangar are closed so breathing isn’t possible, but there are sufficent holes in the construction that the breathing will be allowed and the cooling effect of the low thermal conductivity of the ceramics will provied there effect, which should reduce the wateruse in the mediteranien sun.

The watering system is a simple 40 Lit. sifon system and the final distribution is done with an old tennisball.
Diagram:  -O=
That system provides a pressurefall of the waterflow from the pump from my robed citroen,  which is quite strong, and provides a homoguenos watering in the tubes that finally brings the water to every plant.

My garden is a outdoor and fare fare away garden for long time  beeing independent and to grow the heavy stuff root vegetables :)  So it will work with a carbatterie that will provide the 12 V for the pump and the humidity sensors. Here the final picture i took before leaving to paris. :)

garden and electronics

As you know re:farm has its own electronic hardware.  A  selfdesigned electronic card that is a all in one solution for the electronic enthusiastic farmer. A full functional adruino on board, humidity sensor,  light sensor etc etc. // detailed information on the wiki ->re:farm on vacation board
I haven’t paid for it till now, so i dont know the price for it. Just to mention that. It comes naked with all the parts that you can than later sold onto it by yourself. Quite a funny task. I had hardly ever solded electronics chips, something that is quite small and fine to work with.  Generall i  had a littlepit of respect for that small electronic parts, at least for the digital parts. They break easily, or at least you think, but this is something that changes when you get used too working with them. It changes from esoteric to something quite physical, which i think is a good step ahead. The solding is quite simple. I followed the manual made by hernani. Now with the wiki it is way more easy i think. I just solded one part wrong. The electronic parts look quite the same and the diagram hernani made was usefull but strange but true – one photo says more than a diagram:).

Solding the card is quite an easy task and you can make it all in one day easily whitout any previous knowledge. The testing is a bit more complicated. I have a basic knowlede of adruino and electricity, but something simple how do i plug this thing in needs his own tutorial, but with the help of hernani we made the first testing with my waterpump and my re:farm on vacations board is ready to let it rain.
The foto shows hernani, with my card hooked up to the powersupply of an old computer and the waterpump from my car that found his final rest in a car cementary here in Barcelona.  Rest in peace Astrobotnia , at least some of your parts get reincarneted in an urban garden. That is quite a good afterlive.

garden and wheels

Building a garden with wheels with recycled materials that you find on the street is not a easy task.  If  you want some design, the task is even harder. My solution is the ready made solution (thank you marcel duchamp). The shopping cart. In spain called carro de compras fullfills this purpose perfectly. With dimensions of 90x35x45 cm it nearly reaches 145 Lit of volume. That is quite okey for a small home garden with wheels.  When you look at the picture, than you see that it is hardly too imagine to design something more adequate than that ready made shopping cart for our purpouse. The wheels could be bigger and the mesh smaller , but for something that you can find on the street it is quite a solid solution. Big space for the  water tanks, solid welded metal construction, handy handle to move that thing,  comes with four wheels and it fits through the entrance door. Yes i’m quite happy with my solution. :)

garden of soupgreen

makes  hot salty water tasty

The garden of soupgreen will consit of a mixture of root vegetables. It is a mixture of vegetables that are used for a wide range of recepts but i prefiere tu use them in there most common way. To make a clear soup out of it. It is simllar to green caldo here in spain. Basicliy it is a very comon mixture of vegetables that are used in all over europe but its origen is the northern region of europe. As generall soup is a winter food. It makes you feel well and heats you from inside. Good against colds and supports your wellbeing during wintertime. I love soup!

The ingredients:

– cleriac
– parsley
– leeks
– parsley root
– rutabaga
– chives


Makeing a clear soup:

Just add nearly the same amout of those things you see on that picture above for 1 liter of soup. This is no  quantum physics so the amounts doesn’t have to be so precise. I prefiere the doble amount of  cleriac because it is very rich in taste and i like it a lot. Fill the bole with water and add min. one spoon of salt. Add the soupgreen and cook it on low heat till the carrots are soft. Could take 20 – 30 ‘min.


makes your clear soup a little bit thicker. You prepaire the Einbrenn before you start making the basic soup.


Basically I dont care too much about the amount of butter or flour. Thats because I dont have a balance and you can’t measure butter and four volumetricly in a comperative way. So I use 1 spone of butter and 2 spoons of flour. Melt the butter on low fame. Add 2 spoons of the flour. Add the flour gently. Mix it till it reaches a very dense consitance. It should become a dense liquid/paste and not lumpy. If the conistance is good you add one glass of cold water and mix it all up. Cook it for min. 5 minutes; better 10 that the starch opens. Thats importent for the flavor. Einbrenn or Roux is very commen in cooking. This recept for soup is called the white roux and is the base for white sauces. If you heat the flour butter mixture longer till it gets dark, it is the base for dark souces. You use that for meat dishes etc..


This is a traditional austrian soup that combines the best things in the world of cooking! Creeps and soup.

How to make creeps:


So for me when I’am hungry I use 2 eggs, half a liter of milk and than add the flour till it reaches a dense consitence. I have no balance so I add flour till the mixture gets semifluid and it dosen’t taste to much like flour. If  you added to much flour, add more milk for equibrilation. Always but a little salt to the mixture.
Heat vegetal oile on a hot fame and try too make the creeps as thin as possible. They taste better when they are thinner. When you are done. You roll them and cut them in small strips. That is what in Austria is called “Frittaten”.

Add the amount of frittaten you what to eat and add the hot soup. Add small cut chives at last and thats it and dont forget a littlepit of pepper. Enjoy your winterday.