0 New arm mockup

In addition to a pair of new hands for the robot, I am also experimenting with a new design for the arm. At the moment I have created a mock-up in cardboard so that I can make changes easily. The new arm adds shoulder and wrist joints that were not previously included in the design.

Many thanks to +Western New England University for donating the pens which will be used to make two new hands for the robot. For anyone interested in how the pens will be used checkout my original post here. The driving force behind the design of this robot is to design a way for humanoid robots to be constructed with minimal costs by taking advantage of materials that are radially available, and also recycling to help reduce costs.

Happy Earth day everyone and thank you for your continued support!

Detail: New arm mockup

0 The Joule Thief

This is a pretty cool device that is designed to steal every last drop of energy from a power source such as an old battery and use it to light the LED. The led I used is from a grow-light I had that got killed by a power surge. Some of the LEDs from the grow-light were still good so I used one of them. I made this joule thief a few years ago and it has been running off of a small lithium battery and a solar cell ever since. It hangs from a string in my indoor greenhouse lighting plants on the bottom shelf.

Some instructions for making your own can be found at: http://blog.makezine.com/2007/11/02/make-a-joule-thief-weeken/ #MAKE  

Detail: The Joule Thief

0 The Unnecessary LED

As human technology becomes ever-more advanced there are many ways to be benefited by what is available. Technology now (as of 02/02/2011) doubles in advancement every 18 months. However, even as we progress into the star-trek future that people have always dreamed of there are a few things that hold us back. The main issue is economy, people are just to concerned about money to care about producing products that are truly energy efficient or made to the highest possible standards. Why do many energy efficient appliance have a small light that is always on? When that light is on, it is using electricity. The lights in these appliances are called LEDs (Light Emitting Diodes). LEDs use much less electricity than other light sources but in order to be used in an electric appliance standard wall-socket AC (120 volts) has to be converted to around 1.2 volts. This conversion consumes electricity in the process by converting it into heat which is then lost to the environment around the device. Electrical resistance is further needed to bring the voltage down for the led to use which results in more electricity being converted into heat. In the end this consumes about 0.9 kWh (kilowatt-hours) per year. This means that you only pay about 10 cents per led per year. Not so bad, right?

Based on the above value, imagine if you were able to add up the number of constantly lit LEDs in the world. It would be astounding how much electricity is simply waisted. It is hardly noticeable when you take ten cents from someone but you only need to take ten cents from ten people to make a quick buck.

Almost every modern electrical device has one of these always-lit LEDs. Heres a few examples; Laptop computers, servers, cell-phone chargers, battery chargers, air conditioners, televisions, cable-television box, digital-television antenna, DVD and blue-ray disk players, digital thermostats, ovens, washing machines, dryers, AC power-strips, and even some refrigerators.

Here is a simple solution: all you need is a power-strip with an on/off switch (preferably one that does not have an LED in the switch so that it lights up when the power-strip is on). Most power strips have two holes in the back so that you can mount it on a wall. This can be handy because you can mount it in a convenient location. Just plug the power-strip into the wall-socket and plug your electrical devices like your TV and DVD player into the power-strip. This will allow you to completely turn off appliances just by flicking off a switch when you are finished with them.

NOTE: some devices still consume power even if they don't have a power indicator LED. You can check your appliances that you leave plunged in to see if they are waisting electricity by placing your hand on them and feeling for warm spots. These are spots where there is large transistors, resistors and power transformers that are converting electricity into heat.

Shutting off your electronics will also extend their life. Most electronic devices and appliances are designed to have a specific lifespan, so they are only built to last so many years. By turning of electronics like your TV and Computer when you are not using them and making sure that the device is not secretly consuming electricity you reduce the excess heat which can damage silicon in transistors and Integrated Circuits.

Detail: The Unnecessary LED

0 Alternate Power Sources for Robotics

One of the biggest limiting factors for robot builders is having enough power to provide to all of the electronics running on their robot. Salvius is currently powered by a 12 volt 75 amp battery that provides more than enough power for hours of run time. Unfortunately the battery's weight is a major hindrance. The battery weighs just over 50 lbs and is stopping me from making Salvius into a biped robot. I cannot add legs until I have a smaller but equally efficient power source for the robot. If I were to build legs for the robot now there would simply be nowhere for the battery to go.

I would love to be able to make a power source for a robot that is as versatile as the digestive system in animals. A biological digestive system takes in raw materials and breaks them down in order to release energy that is stored in the bonds between atoms. If I had unlimited space in my robot I would likely build a combustion chamber that could burn any combustible material in order to generate electricity for the robot. The design would likely be based off of the Hero Steam Engine. The engine is a very simple device that spins as steam is pushed through it.

Obviously the Steam Engine wont work in the robot due to size restrictions so another alternative for power is solar. Solar cells are great but they could be heavy on a humanoid robot once you get enough to charge the battery. This also does not remove the need for a heavy battery all together but it still is another option to consider.

The last power source that I have done minor experimentation with is Hydrogen fuel cell technology. Fuel cells can now be build at home thanks to commercially available components. The thing that is important to remember if you are planning on using a fuel cell is that you still need to be able to supply it with a supply of fuel. Hydrogen is the most abundant element in the universe. It also contains more energy per pound than gasoline. Unfortunately Hydrogen usually is already bonded to another element so there needs to be a way to get it in its pure form. This can be done many ways. One way to produce hydrogen gas is through electrolysis. Another way that could be considered is through biological methods.



It would take an algae farm the size of the state of Texas to produce enough hydrogen to supply the energy needs of the whole world. It would take about 25,000 square kilometres to be sufficient to displace gasoline use in the US; this is less than a tenth of the area devoted to growing soya in the US but would equal the size of the state of Vermont, or three times the size of the everglades swamp in Florida, all dedicated to raising this form of algae. - Wikipedia

The big jar of slime you see in the photo above contains algae along with a number of other pond-dwelling organisms. This jar represents a contained ecosystem which survived for two years remaining completely sealed the entire time. The contents would have likely lived longer had I not been negligent and forgot to move it back into the sunlight after cleaning the windows. This shows how robust algae is and how easily it can be cultivated in small containers. I tried growing similar samples in petri dishes with even better success. I can just imagine a robot with a tank of algae on its front standing in the sunlight to help with the production of hydrogen by the algae. This process is perfectly clean and produces no pollutants in the process.

Researchers have found a metabolic switch in algae that allows the primitive plants to produce hydrogen gas - a discovery that could ultimately result in a vast source of cheap, pollution-free fuel. Hydrogen, which can be used as a clean-burning fuel in cars and power plants, is virtually limitless in availability, because it is part of the water molecule. It is a candidate to become the world's primary fuel in coming decades. But until now, it was obtainable in quantity only through relatively expensive extraction procedures involving the electrolysis of water or processing natural gas.

Cars already have been developed that run on hydrogen-powered devices known as fuel cells. These vehicles are virtually pollution-free; the only substance emitted from the tailpipe is water vapor. They do not release carbon dioxide or other heat-trapping gases, which are widely considered the primary culprits in global warming. Fuel cells big enough to power electrical generating plants could also be built. “Our long-term goal is to develop strains of algae that we would grow in mass cultures to produce enormous quantities of hydrogen gas,” said Melis. “But at this point, we have to improve the production performance.”

It would take an algae farm the size of the state of Texas to produce enough hydrogen to supply the energy needs of the whole world. It would take about 25,000 square kilometres to be sufficient to displace gasoline use in the US; this is less than a tenth of the area devoted to growing soya in the US but would equal the size of the state of Vermont, or three times the size of the everglades swamp in Florida, all dedicated to raising this form of algae.

"Green algae can produce hydrogen gas, H2, in a process called "biophotolysis" or "photobiological hydrogen production." This process is carried out by photosynthetic enzymes, which split water to obtain electrons, excite these electrons with photons, and eventually use these electrons to reduce 2H+ to H2. The scientific challenge associated with this approach to hydrogen production is that the enzyme that actually releases the hydrogen, called a "reversible hydrogenase", is sensitive to oxygen. The process of photosynthesis, of course, produces oxygen and this normally stops hydrogen production very quickly in green algae. So, to overcome this problem, we are generating O2-tolerant, H2-producing mutants of the green alga Chlamydomonas reinhardtii by various genetic approaches. The ultimate goal of this work is to develop a water-splitting process that will result in a commercial H2-producing system that is cost effective, scalable to large production, non-polluting, and self-sustaining."-Maria Ghirardi

Detail: Alternate Power Sources for Robotics

0 Salvaging RC Vehicle Parts

Its getting close to the wire now so to say. My robot project operates without any real set dates for when I do things or release updates. However, it is my goal to have Salvius fully mobile before August 30, 2012. Today I stole salvaged the RF receiver out of an old RC vehicle in order to satisfy my need for a quick way to control the robot's arms. Ideally I would like to have more controllers that I can use with the Arduino but I don't have the money at the moment, nor do I have controllers picked out if I did have it.

Detail: Salvaging RC Vehicle Parts

0 Arm motor gear box

The photo above shows a gear box from a pair of cordless electric hedge trimmers that I had taken apart a few years ago. The sheers were damaged but the motor was fine so I saved the gear box. Today I made a mount that will allow me to attach it to the robot. The motor is geared for torque but it is still pretty fast. I'm not sure exactly how I am going to use it yet.

Detail: Arm motor gear box

0 Salvaged Parts

Salvius is partially named after the fact the many of the parts that the robot is made up of were salvaged from damaged appliances and lots of things that most people would just throw away. I have labeled a photo to show some of the major parts of the robot that were recycled from other projects and saved from my trash can. In fact some of the only things that I have purchased so far are minor components like LEDs and electronic parts like the Arduino Uno.

(You can click on the image to view it larger)

Detail: Salvaged Parts

0 Solar Powering a Humanoid Robot

The schematics are done; Salvius is now ready to start charging the small battery that powers the Arduino micro-controller in his head so that the robot can operate longer between chargings. One of the issues that occurred in the design of the solar battery charger was that I did not want to overload the Arduino by connecting a battery as well as an array of solar panels. To solve this I added a small toggle switch (SW) that allows the battery to be switched from powering the Arduino to be charged. Although this switch over has to done manually for now it could easily be made an automatic process by adding a DPDT (double-pole double-throw) relay in the place of the switch. The schematic bellow shows the layout for this circuit. J1 is a plug that is connected to the solar panel array, J2 is a plug connected to the Arduino's power jack, SW is the switch, and B1 is the rechargeable battery.

At this point the solar panels together produce a total of 12.01 volts in direct sunlight. This seems to be more than enough to keep the 9.5 volt battery pack fully charged.

Solar panel array to test battery charger.

Detail: Solar Powering a Humanoid Robot