Continued working on GUI for using photo-gates for various experiments. Writing python code for this single GUI with which user can access different experiments involving time measurements.
The program is giving time-out errors while using two photo-gates simultaneously. Need to debug all the errors by tomorrow so that this GUI will be ready.
…. About Light Barrier as Photo sensor ( Source expeyes.in)
A photo-transistor plus LED combination can be used for measuring light transmission and for sensing the timing of mechanical movements. The LED is powered by SQR1. The collector of the photo-transistor is connected to SEN, which is connected to 5 volts through a 5.1k resistor. The voltage at the collector of the photo transistor changes according to the amount of light falling on it. The built-in analog comparator on SEN input is used for timing measurements when the light crosses a certain threshold.
Today I worked on python programs for Mechanics – friction experiments and documentation of mechanics experiments. Started working on a GUI for using photo-gates for different time measurements. This can be used for various experiments involving precise time measurement.
today, I could get the apparatus for energy conservation experiment prepared from local carpenter in wood. Its working fine. Wrote python program for the experiment. User can enter the value of initial height of the metal sphere, to calculate Potential energy. When the Sphere roles between two photo-gates, time can be measured with microsecond accuracy and velocity and hence kinetic energy can be calculated. The results show that Initial Potential Energy is equal to final Kinetic Energy and hence proves the Energy Conservation Theorem.
This simple experiment is very useful for high school students.
Did required modifications in the main GUI program ” CROPLUS” written by Dr Ajith Kumar, to access these new experiments. Uploaded this program on my GIT repo.
Now writing a new program for a GUI to access these mechanics experiments separately.
Next week I will finalize sound experiments.
Conservation of energy is an important concept in mechanics. It can be demonstrated easily by calculating total energy of a body at different positions during its motion. Today I planned and worked on the set up of a new and simple experiment to demonstrate this.
The experiment can be done in two ways
- Using Ultrasocic sensor : SRF 05 module transmits a burst of ultrasonic pulses. The ultrasonic pulses reflect off a target and return to the face of the sensor. The sensor measures the time between the trigger rising edge and the echo rising edge. It uses this time and the speed of sound to calculate the distance to the object. To determine velocity, it uses consecutive position measurements to calculate the rate of change of position.
- Using Photogates : A photogate monitors the motion of objects passing through its gate, counting events as the object breaks the infrared beam. If the size of the object is known, by measuring the time an object blocks the gate, you can determine the velocity.
I could do the experiment with two photogates using a small spherical ball rolling on an inclined plane.
Tomorrow I will get the wooden ramp for this purpose. Program to measure the time and to calculate Kinetic and Potential energy is ready.I will also try to do the same experiment using SRF module.
Oscillations is a very important phenomena in physics and has an extremely wide range of occurrences.
They are visible in the swinging and cushioning of cars or suspension bridges. In Nature, oscillation always occur as coupled ones.
Today I started working on setting up an experiment with two spring pendulum to study oscillations of coupled pendulum. In this experiment we will try to get the characteristic frequencies and investigate the phenomenon of beat-vibration with two coupled spring pendulum.
Continued to work on an experiment to study damping oscillations of spring in different media.
Worked on the python program to solve errors in fitting the curve to obtain damping factor. Repeated the experiment with air, water and glycerine as medium.
Experiment to investigate the damping effect of air, water and other viscous liquids on spring oscillations can be very interesting if done with a computer interface. Currently these set-ups are available for very high cost and come with proprietary and closed source software. They general use Rotary motion sensors which are costly.
Since yesterday I was working on this idea of setting up an experiment with low cost apparatus using ExpEYES. Tried using a simple DC motor to fetch the data and plot oscillations. ( we were using this method for digitizing pendulum waveform). After multiple trials now the setup is ready and got amazing results.
The schematic diagram and my home made set up is here…… 🙂
On release after being pulled down, a spring oscillates with decreasing amplitude due
to viscosity of liquid, and finally becomes stationary. Here DC motor is our low cost rotary motion sensor… 🙂
Here is the screen-shot of the waveform generated in water. Tomorrow I will try this experiment with other liquids like glycerin.
Some errors occurred while fitting the curve need to find out the problem.
Information from Hyperphysics was of great help
The code is here….. (Used program for pendulum waveform with little modifications)
( From Monday 7th July 2014 to Sunday, 13th July 2014)
This week till 11th July 2014 I was in Montpellier, France, participated in Libre Software Meeting RMLL-2014. Returned back today early in the morning.
This week I had experienced some good and some horrible things too.
The good things ….
- I got to meet many people actively contributing to Free Software World.
- Had interaction with Richard Stallman (RMS) of Free software Foundation. He was happy to see development of ExpEYES.
- I could spend some time with Georges who helped me with my GSoC project. We worked on GUI’s required for mechanics and sound Plugins. He also guided with packaging.
& The horrible things
- Loosing my baggage in air travel….lost my acoustic and light sensors, ExpEYES kit, A tablet and other asccessories required for my ExpEYES experiments 🙁
………. Fortunately I have some extra ultrasonic sensors at home.
The only productive thing is that I could work on GUI’s for experiments with friction, Doppler Effect as I had data obtained from experiments that I did at home before leaving to France. As I am lagging behind my planned schedule I need to accelerate and work 24X7 this week so that I can finish documentation of all experiments and GUI’s by 20th of this month as planned.