Thursday, February 24, 2011

Awaiting XO's

The project is now waiting for the XO's to arrive. They are currently delayed in Quito, possibly for customs.

The research that I've done so far has indicated some interesting options for the UV Sterilizer.

It can be used as part of a humanitarian relief package without any software whatsoever. Simply plug it into the USB port to turn it on, and unplug it to turn it off.

As an educational tool, it has a lot more requirements and a lot more possibilities.

Before I continue the project with physical work, I'll have to do some research on the local laws regarding construction of a prototype, testing samples, and whatever else pops up. I might be required to apply for a permit. Also, I will have to go consult with a university that has a microbiology program and see if they can assist with testing the prototypes.

The next phase that I will be going through, assuming it is possible, is constructing two prototypes. Following that, I'll be testing them with the XO's.

Saturday, February 19, 2011

More Options and Thoughts

Is there enough power from the XO USB port?

1. Specs

"2.12.1 USB
The CL1 supports three USB 2.0 ports, two on one side of the display and one on the other. These are all USB type A connectors, for connecting to peripheral and storage devices. Unlike a regular laptop, which provides up to 2.5 Watts per USB port, the CL1 provides a total power consumption of 5 W for all three USB ports. This may be shared equally among all the ports or drawn through a single one, but
cannot be exceeded."


2. USB wire hacking, and a useful adaptor for sensors:


3. 5 Watt UVC bulbs:




*. Note: From website c, a safety precaution: "SAFETY NOTE / WARNING: Radiation from UV-C lamps (ultraviolet C - 253.7 nm wavelength) is harmful to eyes and skin. Equipment using these lamps must screen them completely from direct view."
*. Note: Also from website c, "For optimal performance, replace the bulb in your Ultraviolet (UV) device every year even if it continues to light, as over time the bulbs will lose their effective germicidal light spectrum."
*. Note: And more interesting information that air can be purified as well from site c, "effective tool for eliminating microorganisms such as virus, bacteria, algae, mold and yeast in the air and impurities in water."

4. Quick thought on LED UVC. If it is possible, LED bulbs would provide a low-energy mercury free alternative to other UVC bulbs. They would also be more durable and longer-lasting, probably. However, why did they have a different nm wavelength than the one known to be germicidal?

5. 5 Watt USB Power Adapter from US plugs (I need this in reverse, usb to US plugs):


6. Wall plate adapter (Might be useful):


7. USB powered 5 volt Optical Probe:


8. USB power cables:


9. Can a standard USB cable be adapted easily to the two prong connector and will it supply the right voltage? This seems like the simplest solution for getting a basic product going for test purposes.

Friday, February 18, 2011

Research on UV bulbs

I have done some research on UV light bulbs and am adding this information to be considered and reviewed. After reviewing it, I'll have to filter it to see what information is useful. Pardon the pun.

Relevant XO specs:

1. Battery: Capacity: 22.8 Watt-hours (LiFePO4); 16.5 Watt-hours (NiMH);

2. USB: Three Type-A USB-2.0 connectors; up to 1A power supplied (total)

3. From:

UV Sterilizers (What differences between different types?):

1. Google search:

2. Aquarium bulbs:



3. Other sterilization options:

a. Ozonizers (requires protein skimmers?):

b. Reverse Osmosis:

4. Notes about UV sterilization for aquariums (How does this relate to human

a. A UVC bulb is necessary. UVA and UVB would be ineffective.

b. UVC will have less than 280nm wavelength, and preferably around or below

c. The water to be treated must be in range of the light. (What is the

d. These considerations from the above link. Key points from this link are

1. Amount of water that is going to be treated (liters or gallons).
2. Where the UV Sterilizer will be placed in the aquarium setup.
3. Power rating of the UV Lamp.
4. Service requirements and servicability of UV Sterilizer unit.


*. Always purchase a Sterilizer with at least 25% more treatment capacity
than the size of the area that is to be treated.
*. It is best to maintain mechanical, chemical, and biological filtration
when using a UV Sterilizer. The "dead" material needs to be removed.

Section 4 all from here.

5. New Technology: LED UV, ideal for use in this project?


6. Residential UV sterilizers:





Material considerations (still in my concept phase):

1. The UV light bulb must be strong, flexible, and allow sufficient transmission of light to the water being treated.

a. Is this possible?

b. Which material gives these attributes for the lowest price?

c. Can a standard UV sterilization bulb be encased, or will it require a new kind of bulb?

d. Which bulbs are commercially available that would fulfill this role? If none, which might be adapted? If none, how do I make one?

e. What power considerations are there for UV sterilization bulbs? What is their power consumption rate, activation cost? Will the XO have enough power to activate them?

f. Do UV sterilization bulbs require any components that are difficult to acquire?

Concept Phase

I am currently going through a concept phase, generating ideas that might be included or useful in the project.

In consideration of the hardware itself, I am thinking of using a USB connection to power the UV device. I need to consider the following:

1. Does the XO have powered USB connectors? The ideal answer here is Yes. Otherwise, the device will have to have an independent power source.

2. Turning the device on and off.

a. The device should have a timer.

b. It should be mechanical instead of electronic, to conserve power for more water sterilization. It will have to be attached to the device. A mechanical stopwatch might be ideal for this, with a power-saving trigger that turns off the UV light when sterilization is complete. This solution may be the easiest and quickest to implement, although it adds to hardware costs.

c. A digital timer on the XO display is a possibility if there is enough power. This would be ideal for educational purposes and could be incorporated with relevant software. Functions included with this software would be Start Purification, Stop, Diagnostics, and perhaps an efficiency gauge measuring water purified in relation to power used. This solution reduces hardware costs but increases software demands.

d. A timer is not necessary if this device works in tandem with biological/water purity sensors that may be developed by another project. This would combine projects into a larger, more complex development.

3. An option to minimize power use by XO's while triggering multiple units to engage in water sterilization mode.

a. Can Mesh Network be used to send commands to multiple XO's to trigger their USB ports, thus turning on the sterilization device, without activating their cpu's?

b. If so, then software can be developed for a management unit, which would send the commands to the other units through Mesh Network. This engages sterilization of multiple bottles of water simultaneously and has the added benefit of saving valuable power from being used by the processors.

c. Mesh Network

OLPC UV Water Sterilization Project

This is the initial post for this project. This project blog is presented here both for reference and for students who may eventually use the device.

My name is Corbin, and I've submitted a proposal for an OLPC project, which involves creating a USB powered/attached water sterilization unit. This unit would be included in OLPC deployments in areas where water quality is a concern, as well as with XO Disaster Relief kits, possibly in relation to the research and program detailed here:

On the Map:,-63.3191,-4.1631,-91.0706