WatsOn

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Part of the biosensor system Cellock Holmes are our agar chips. They contain our engineered sensing cells that fluoresce in the presence of the pathogen Pseudomonas aeruginosa. However, bacteria are small and the fluorescent signal cannot be seen with the naked eye. Thus the central question "What's on the chip?" remains.

To answer this question we present our measurement device WatsOn.

WatsOn fulfills several tasks in our system:

incubate the sensing cells and the sampling chip
prevent escape of potentially sampled pathogens and our genetically engineered cells
illuminate the chip with the right excitation wavelength for GFP or iLOV
take photos and timeseries of the chips
analyze the fluorescence signal
give feedback to the user about the presence or absence of P. aeruginosa

WatsOn is designed such that it can be easily copied. Our work heavily emphasizes the Open Source concept. Therefore, the construction manual and all technical detailes are published on our wiki. Analogous to our OD/F device, we used low-cost and easily available parts.

Measurarty

Measurements

Software Evaluation

Secret Ingredients

Arduino Sketchbook (.ino)

Build your own WatsOn

If you want to create your own WatsOn at first check the following list of necessary devices.

Table 1: Needed number of pieces, components and costs for building your own measurement device

number of pieces	components	costs [$]
1	[http://www.prolighting.de/Zubehoer/Farbfilter/Lee-Filter_HT/Lee-Filters_Musterheft_Designer_Edition_i174_3965_0.htm filter slides] (medium yellow 010, sally green 505)	5.17
1	[http://www.dx.com/p/uno-r3-development-board-microcontroller-mega328p-atmega16u2-compat-for-arduino-blue-black-215600 arduino UNO R3]	11.65
1	[http://www.dx.com/p/arduino-2-channel-relay-shield-module-red-144140 2-channel relay shield]	3.46
40	jumper-wire cable	2.99
1	[http://www.dx.com/p/2-54mm-1x40-pin-breakaway-straight-male-header-10-piece-pack-144191 40er male header (10-Piece Pack)]	2.72
1	[http://www.dx.com/p/jtron-2-54mm-40-pin-single-row-seat-single-row-female-header-black-10-pcs-278953 40er female header (10-Piece Pack)]	2.60
1	[http://www.dx.com/p/prototype-universal-printed-circuit-board-breadboard-brown-5-piece-pack-130926 circuit board]	2.99
1	[http://www.newark.com/pro-signal/rp006/audio-video-cable-hdmi-1m-black/dp/96T7446 HDMI cable]	1.87
1	[http://www.dx.com/p/hd-053-high-speed-usb-2-0-7-port-hub-black-174817 7 port USB hub]	6.71
1	[http://www.dx.com/p/dx-original-ultra-mini-usb-2-0-802-11n-b-g-150mbps-wi-fi-wlan-wireless-network-adapter-black-252716 WLAN USB stick]	5.35
1	USB mouse and keyboard	12.50
1	[http://corporate.evonik.com/en/products/pages/default.aspx case acrylic glass XT 6mm~0.5²]	50.65
1	spray paint for acrylic glass	6.54
1	[http://www.newark.com/raspberry-pi/raspberry-modb-512m/raspberry-pi-model-b-board/dp/68X0155 Raspberry Pi model B board]	35.00
1	[http://www.newark.com/raspberry-pi/rpi-camera-board/add-on-brd-camera-module-raspberry/dp/69W0689 Raspberry Pi camera module]	25.00
1	[http://www.pollin.de/shop/dt/NzUwOTc4OTk-/ 7” display]	50.50
1	[http://www.dx.com/p/diy8-x-seven-segment-displays-module-for-arduino-595-driver-250813 8-segment display]	3.86
2	[http://www.dx.com/p/arduino-dht11-digital-temperature-humidity-sensor-138531 digital temperature sensor DHT-22]	7.50
1	aluminum block 100x100x15 mm	14.23
1	[http://www.dx.com/p/tec1-12706-semiconductor-thermoelectric-cooler-peltier-white-157283 Peltier heater 12V 60W]	4.49
1	power supply	32.89
6	[http://www.leds.de/Low-Mid-Power-LEDs/SuperFlux-LEDs/Nichia-Superflux-LED-blau-3lm-100-NSPBR70BSS.html superflux LED 480nm]	7.50
16	LED 450nm	7.50
1	cupboard button	1.24
-	total	308.55

Wiring of our device

	Start building your own WatsOn by assembling the base plate, the sides and the interior wall.
	Fix the Peltier heater on the back of the aluminum block and place it in the hole of the interior wall. Arrange the 4x4 450nm LEDs and the 2x3 480nm LEDs
	Assemble the camera holder with the camera and the corresponding filter slide on the lower part. Over the camera you can place the temperature sensor for measuring the indoor temperature. Finally put the fan on the back of the camera holder.
	Connect the electronic components on the outside and the inside according to the wiring diagramm.
	Put together the drawer.
	Position the front panel and insert the drawer.
	Place the temperature sensor for the aluminium block temperature directly on the block and put the back panel in front of it.
	Setup the power supply and connect all devices to either 5V or 12V.
	Mount the device on top of the power supply casing. Add the display and apply some stickers to enjoy your custom-made WatsOn.

Contact Disclaimer

Team:Aachen/Project/Measurement Device

From 2014.igem.org