Friday, August 19, 2011

Two options for finalizing the project.

There are basically two ways to finalize this project. The first way is for someone to purchase a UVC LED bulb that will operate on 5 volts and send it to me. The second way is for someone with electrical knowledge to let me know exactly how to transform my 5 volts (or ~10 volts from two XO's) so that we get up to 110/220 volts to power the aquarium uvc bulb.

I contacted the company that sold me the uvc bulb, and they informed me that the bulb was simply mislabeled as 12 watts, and is in fact a 5 watt bulb.

Saturday, June 25, 2011

Stuck for the Moment

I encountered a problem getting the electrical components to match. The bulb, while it said 5 volt and 5 watt on Amazon, is apparently 120 or 220 volt. It requires a special socket that I've not been able to find yet.

Also, if it becomes necessary to generate additional voltage, I would either need 22 XOs or a vehicle power inverter (the kind that plugs into the cigarrette lighter socket) that transforms 12 volts to 220. These inverters are expensive, and I can't afford to buy one right now. With one of these, I might be able to transform the 10 volts from 2 XOs to enough voltage to get the bulb to function. That is my hope, anyhow.

Right now, it seems that whether this is possible with the given bulb or not might not matter in a few years when the UVC LED bulbs come down in price. Since LED bulbs are generally cheaper, I look forward to the technology becoming more widely available at cheaper prices.

Pictures of all the parts are waiting on a picture editing program being installed on a laptop for proper contrast and lighting.

Friday, May 6, 2011


It has been a while, but the light bulb is finally here. I also acquired an electronic ballast that I may need to make the bulb work. Unfortunately, the smallest available goes up to 22 volts, and may be too high for the bulb to work. However, if it does work, that would be great.

Now I am considering whether I need a quartz sleeve to protect the light bulb, or if it will be fine in contact with the water. I believe that it will be fine in contact with the water, and may skip this step.

I'm considering using empty Gatorade bottles for this experiment, since the lamp is too wide to fit in narrower mouthed bottles. I may need to develop something to keep the electrical part of the device from getting wet. I am considering buying electrical tape for this, as well as using popsicle sticks to support and balance the bulb on the bottle. Additionally, I need to purchase some 5 volt wiring to make connections and a voltmeter as a safety consideration. I should be able to complete these tasks within the next month or two.

I will post pictures of all of the parts once I'm ready to start building.

Following creation of the device and basic power testing on the XOs, I will be looking for a local University to work with to obtain necessary permitting for sample collection and testing.

Thursday, March 31, 2011

Looking Ahead

As I get closer to being able to build the Sterilizer, I am also researching possible laws that may govern the conduct of research here. According to this website, I may need to apply to the Ministry of Environment (Ministerio de Ambiente) in Ecuador for appropriate permits before proceeding with sample collection:

Unfortunately, that website notes that applications need to be made 6 months in advance. I'll have to see what can be done there, and also look into a collaboration opportunity with a local University concerning the project.

I am still awaiting the additional parts needed to make the sterilizer, and once I have them I should be able to determine if I'll need 5 watt electronic ballast to start the bulb.

One Possibly Useful Piece of Hardware

Tester Finds Problem

My QA tester discovered a problem with the touchpads. I'll recheck them later to see if they're okay.

They have arrived.

Thursday, March 24, 2011


The XO's have been received. Both turned on, and appear to be mostly operable. There has been a small problem with the touchpads and the cursor not responding correctly, but hopefully that will clear up. I hope to be adding some pictures soon. It turns out I may need ballast for my bulb to start properly. If so, I'll have to locate some ballast, which should be easier to find than the bulb.

"All lamps are powered by ballasts that provide the starting electrical voltage to ionize the gas in the UV lamp and then limiting the current to the nominal level. Lamp ballasts can be either magnetic or electronic. The LED UV lamps do not require ballasts for their operation." from here.

Friday, March 18, 2011

More waiting...

The XOs are supposed to arrive soon. I should also have other parts to build the sterilizer soon. Although, I may have to do more research on the bulb first.

Saturday, March 5, 2011

Holidays delay arrival of XO's

Due to a holiday this Monday, I will probably not be able to receive the XO's until next Monday. Any boxed package has to be received on Mondays, here.

I've added a link to SODIS in the list of links to the right. It is a good and effective water treatment solution for longer term sustainable water sterilization in larger quantities. Use of the UVC device could be seen, then, as the immediate solution to drinkable water in a disaster situation.

Possibly, 2 or more liter bottles could be wrapped with thermal blankets (the cellophane/aluminum type) to increase the effectiveness of the UVC exposure by reflection while preventing exposure to human eyes and hands.

Sourcing of a 5 watt UVC bulb is proving to be difficult. If I have to order them from the US, it could take up to a month or two to receive them.

I've requested financing support, but have not received any interest in the project with regards to financing at this time.

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:

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