Maunfacturing our base.   Leave a comment

After a long descussion with Seamsu Harlon amd Paddy we decied the best way to go about manufacturing our dome based base was to use a former and spin it. This would be  a difficult process and one which we were not two fermiliar with as we had only done the process once befor back in first year but we decided to give it a go.

First we had to turn a timber former so we could turn our base around. We made this former out of hardwood timber as we felt a sort wood would be to soft and may not withstand the pressure of the church of the lathe.

We measured the circumferance of the piece of aluminum we need for our dome and cut it. We decided that1.5 mm aluinum would be the best for the spinning process and would keep our robot at the appropiate weight also. To get the circumferance of the material needed we measured the curve using a piece of paper and rulke as show below the was an accurate an affective method.

Once the we had the material cut we placed the material and and timber former in the lathe for spinning. Soaf and grece were added to the aluminum before and during the spinning processs as

Spinning process taking pace.

  • Make sure to start from the outside and work in.
  • Make sure that you have a firm strong hold on the tool and the ta tool is wedged firmly between the material and the tool stop as show above.
  • Make sure no bodie is around the machine incase any piece flys off and make shure you have you face shiled on and you have a good firm stance.
  • Make sure an appropiate amout of greece has been aplied.

Posted April 9, 2011 by paddyjamiemikey in Uncategorized

Measured Drawing..   Leave a comment

Posted February 17, 2011 by paddyjamiemikey in Uncategorized

Finished Design..   Leave a comment

Posted February 17, 2011 by paddyjamiemikey in Uncategorized

Sensors   Leave a comment

This is something we are new to so it took quite abit of researching to understand how the sensors work. We know that we need two types of sensors, one to detect the position of the opposing robot and one to detect the edge of the ring so as our sumobot stays inside the edge!

Firstly I will go through what we have learned about sensors to detect the opposition. We found 4 main types of sensors that would be relevant to us.

PIR (passive infrared sensor) Sensor: These are sensors that don’t actually emit an infrared beam but simply accept the beam from other objects and can detect where they are. There are advantages with using this sensor such as the fact that it can detect an object from yards away. On the other hand, they are very expensive. Also because they work only on receiving infrared light we are depending on other teams having infrared on their robots.

 

Infrared Proximity Sensors: An IR proximity sensor works by applying a voltage to a pair of IR light emitting diodes which in turn, emit infrared light. The light goes through the air and once it hits an object it is reflected back towards the sensor.

Ultrasonic Sensors: Ultrasonic sensors generate high frequency sound waves and evaluate the echo which is received back by the sensor, Sensors calculate the time interval between sending the signal and receiving the echo to calculate the distance to the object.

Microwave Sensors: Microwave sensors, operate at frequencies of 10 Mhz. They utilize a doppler radar signal which bounces microwaves off of an object, then measures the frequency of the returning microwaves. If an object is moving in the sensor’s field, the returning microwave will be at a different frequency, higher or lower than the original signal transmitted. Microwave sensors offer a greater distance of coverage and are more reliable at greater distances. Microwaves can also penetrate walls

Now I will go through what we learned about sensors that could be used to keep the robot in the ring..

LDR (Light Dependant Resistor):

LDRs or Light Dependent Resistors are very useful especially in light/dark sensor circuits. Normally the resistance of an LDR is very high, sometimes as high as 1000 000 ohms, but when they are illuminated with light resistance drops dramatically.

This is an example of a light sensor circuit :

When the light level is low the resistance of the LDR is high. This prevents current from flowing to the base of the transistors. Consequently the LED does not light.

However, when light shines onto the LDR its resistance falls and current flows into the base of the first transistor and then the second transistor. The LED lights.

Phototransistors:

Like diodes, all transistors are light-sensitive. Phototransistors are designed specifically to take advantage of this fact. The most-common variant is an NPN bipolar transistor with an exposed base region. Here, light striking the base replaces what would ordinarily be voltage applied to the base — so, a phototransistor amplifies variations in the light striking it. Note that phototransistors may or may not have a base lead (if they do, the base lead allows you to bias the phototransistor’s light response.

Photocell:

A photocell is a type of resistor. When light strikes the cell, it allows current to flow more freely. When dark, its resistance increases dramatically. Photocells need some calibration to be responsive in the exact lighting scenario you have. They can be used to detect large or small fluctuations in light levels to distinguish between one light bulb and two, direct sunlight and total darkness, or anything in between.

Posted February 13, 2011 by paddyjamiemikey in Uncategorized

Keeping the sumobot in the ring..   Leave a comment

We now have to consider how to go about keeping the sumobot inside the ring. This is obviously very important as whatever robot stays in the ring longer wins! We researched this on the internet and consulted our peers about this challenge. We have learned that using PHOTOCELLS would achieve this function. The ring will be a black disc and the surroundings will be completely white. The photocell can detect the change in colour and then the robot knows to move away from the white colour.

Posted February 13, 2011 by paddyjamiemikey in Uncategorized

Our final design/working drawings   Leave a comment

Posted February 13, 2011 by paddyjamiemikey in Uncategorized

How will the sumobot move?   Leave a comment

We have been doing alot of research on how our robot will run.

Friction is very important to keep in mind here as it will prevent the robot to move better!

We could use wheels or tracks. Here are some of the images we saw:

http://www.youtube.com/watch?v=c1sgV7UBGUo&feature=related

 

 

Posted February 11, 2011 by paddyjamiemikey in Uncategorized