on the left of the picture you have the prototype me and andreas built for the workshop.
remember this blasting board? ok, finally got the board revised by david prelo :)
soon we will post some more pictures on how to make this board with cardboard and fabric!
yeah, I’ve been working with circuits on fabric mainly because since beijing I don’t have a solder iron. I also don’t want to spend money and energy so fabric seems the most sustainable solution :)
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.
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 :)
são paulo report and some considerations.
we try this one here in são paulo. the nano vacations.
don’t let you misleading by the nano scale. ok, it’s small (the diagram is 1/1) inexpensive 2$+ecofootprint, and can be mostly scavenge in a city.
still on the scale perspective and scales we don’t see, most of our electronics work on micro, nano or pico scale but the above inexpensive ecofootprint can be bigger than the 2$.. can be a 2K$.. we just don’t know.. I didn’t make the maths on the energy embodied nor the ecological impact of our tools.. how many tons of minerals are dig from mountains and were are this mountains?
we extend the live of some materials but we also use a small % of new materials.
we also got “bugs” on the electronics hehehe in january I got this
20 tip 120 on a electronics market in beijing by 10$. when you connect 12v to them they just blow.. so insted of a tip120 darlington transistor I got 20 units of a 12V non reusable bomb that gives a blasting sound. if this is exactly what you were looking for, I can sell them to you:p
so we just setup the watering system without the nano blasting board.
wau, what a place.. full with electronics, friendly people and geeky too :) being geek is one of the most intensify intellectual activities in our days apart of fun, open and creative. thank’s guys ;) you will be a great partner of the SP re:farm group.
back to the small, pretty board: the idea is just to have some control over a system that has a bottle that recovers rain and a windshell water pump that handles the watering. the moister sensor (has a tribute to this guys) was made with local materials.
we got this boxes on a country fair around the corner.
daniela brought her used filter,
we got the water pump 2 doors away by 10RS
we got the soil from an hippic place
the bottle was gently offered by a local store (it’s amazing how people give you things when you ask materials to make a urban farm :)
in 3 days we got local materials, build one re:farm, one vermi-composter, eat good food, good drinks and of course made new friends :) looking forward to come back heheh
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.
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.
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
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 :)