I made WATER BACK CARRIER, a backpack-type carry bone with water
utilization modules which collect rainwater and purify it to
gain hot water and emergency drinkable water everywhere. My
purpose is not only making folk tool from local resources by
digital fabrication. I invented this prototype for archiving and
inheriting precious knowledge of how to utilize local resources
in each community. In other words, through making this prototype
you could learn twisting rope, weaving bamboo, and jointing
wood. And also you would have a chance to know how to get those
materials and how to cultivate their mountain, bamboo forest and
farms. The slide for my final presentation is here.
Water back carrier.
Water filtration unit.
Solar water disinfection container with thermometer.
Working in progress
Screen capture of Rhinoceros. The process of 3D modeling.
This unit consists of two parts: one is a ladder and rack made
of wood, and the other is shoulder straps and back support
cushion made of rice straw. I chose Hinoki cypress (25
mm x 25 mm x 1920 mm) for ladder for this project. This wood is
light, easy to cut and engrave, and smooth. I determined the
ladder's size to fit my own build and cut out the material.
The process of making the ladder.
I used the mortise and the tenon joints one of the most common
joints used by woodworkers. The mortise was made by the CNC
router (Woodpecker) with 3 mm endmill.
The process of engraving by large format CNC router.
The tapered tenon was made by the band saw.
The process of cutting Hinoki cypress by band
I used rice straw, an important by-product of rice cropping, as
materials of rope for shoulder strap and back support cushion. I
made a thick rope for the shoulder straps, and a thin rope for
the back support cushion.
Though I could get enough amount for this prototype Shoro
palm is also useful material for making ropes. Shuro
palm's fiber is durable and resistant to water. Because of its
property the fibers have been used for making ropes to tie boat
and dock (Tomozuna) and connect oar to the boat (Kaihimo).
I plan to use the rope of Shuro palm to fasten
some components tightly in the next prototype.
The process of making rice straw rope.
I folded Washi paper (560 mm x 810 mm) by simple Origami
method and applied persimmon tannin on the surface of the paper
The process of applying persimmon tannin.
I tried to make thiner bamboo stripes but it was too difficult
for me. I really need more training and experience.
Tools for making the thin strip of bamboo.
I applied the thin strips of bamboo as the rib of the
umbrella-like component to collect water. So I made connector
that joins these ribs by 3D modeling and printing. For 3D
modeling, I used Autodesk Project Shapeshifter, which provides
an easy parametric design to create 3D printable models.
Screen capture of Project Shapeshifter. The process of 3D
3D printed connector, modeled by me.
The connector is also part of the water filter. I have thought
that I would like to use a used PET bottle as materials of
container for water filtration unit, therefore I set the
diameter of the connector to fit the inner diameter of 500 ml
Ribs joined by the connector I made.
Finished rainwater collector (bottom view).
Water filtration unit
I made a charcoal for one of the material of water filter by DIY
wood gas stove, which provides heat generation and charcoal
The process of making charcoal by DIY wood gas stove.
I cut the bottom of the used 500 ml PET bottle and turned it
upside down. Then I connected it to 2 L PET bottle for storing
Water filter. From bottom to top: connector, cotton,
charcoal, Shuro palm, and connector.
Solar water disinfection container
Solar water disinfection is a simple method for decentralized
water treatment. Water is filled in a clear container and
exposed to the sun for 6 hours on a clear day. During this time,
the ultraviolet (UV) radiation and heat of the sun inactivate
I chose Sugi cedar butcher block (375 mm x 250 mm x 25
mm) from forest thinning process. I used CNC milling (Roland
Modela Pro II MDX-540) with 6 mm endmill (R3 x 18 x 60) to
engrave the wood.
The process of CNC milling.
The process of painting the container black.
The press-fit box for the input/output device was cut out from
used 4 mm plywood sheet by laser cutter (Epilog Mini 24 Laser:
24" x 12" work area).
The process of laser cutting.
Cardboard prototype (left) and finished press-fit box
I collected the electronics components listed below and then I
designed the board with Eagle referring to the hello board
series in this class.
Input sensor: temperature sensor (LM61CIZ)
Output device: 16x2 character LCD module 16x2 character
CER resonator: 20 MHz SMD (ECS-CR2-20.00-B-TR)
IC regulator: 5V (LM3480IM3-5.0)
Resistor: 1k, 10k, 100k Ohm
Battery and etc.
Screen capture of Board layout in Eagle.
int sensorPin = 7;
// LiquidCrystal display with:
// rs on pin 4
// rw on pin 5
// enable on pin 6
// d0, d1, d2, d3 on pins 11, 12, 13, 14
LiquidCrystal lcd(4, 5, 6, 11, 12, 13, 14);
int tempValue = analogRead(sensorPin);
int tempMilliVolt = (unsigned long)5000 * tempValue
float temp = (tempMilliVolt - 600) / 10.0;
lcd.write(0xDF); // character degrees
lcd.print("C"); // character Celsius
Back carrier: 740 g
Rainwater collector: 100 g
Water filter: 80 g
Water storing unit: 20 g
Solar water disinfection container: 300 g
Thermometer: 210 g (incl. battery: 100 g)
Total: 1470 g
You can download the data file from following link.