• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

Using a Rotary Potentiometer to Detect the Position of a Robotic Arm

Extracts from this document...


Using a Rotary Potentiometer to Detect the Position of a Robotic Arm Plan: A rotary variable resistor would be set up as shown mechanically and electronically: Various different fixed resistors would be tried, with several readings taken for each. I suggest 9 readings should be taken, every twenty degrees starting at 20 for each resistor. That way, a full range of angles can be tried along the whole movement of the arm. Once the results have been obtained, then graphs can be plotted to calibrate the sensor, and from these graphs the most suitable resistor can be chosen for the sensor involved. Initial experiments show that all readings will be in the range of 0 to 5 volts. Results: Voltage across sensor (V) Resistor Used in Potential Divider (ohms) Degrees 100 220 470 1000 2200 4700 10000 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 20 0.35 0.17 0.08 0.04 0.02 0.01 0.00 40 3.14 2.32 1.48 0.86 0.44 0.21 0.11 60 3.98 3.45 2.68 1.84 1.07 0.57 0.29 80 4.23 3.82 3.17 2.36 1.50 0.84 0.44 100 4.42 4.10 3.60 2.87 1.96 1.17 0.64 120 4.46 4.22 3.78 3.13 2.24 1.39 0.79 140 4.51 4.29 3.99 3.31 2.45 1.59 0.92 160 ...read more.


For example, the 100-ohm resistor has 12 readings less than 0.5 volts apart. This results in a low SD, even though the spread is less even). I have also divided the standard deviation by the range to allow for comparison between resistors of different ranges, and quantitative comparison. A larger graph that better depicts these readings is in the appendix. Again, the higher the SD/Range ratio the better for a generalist arm. However, I believe that range should also be maximized, and as such I believe the 2.2k? is the most effective in this role (see below). Linear variation is most desirable for this use in a non-specialist arm. This is beneficial, in a typical arm, because a large and even difference in voltage is present wherever the arm in its arc. A more specialized arm, for example in a car factory, might need great accuracy in a certain position, such as near the car, and less accuracy in others, like storage position, and well above the car. This arm would require a large spread of potential difference over certain angles, and smaller spread of potential difference over others. ...read more.


Its accuracy and range would be extremely good, however. Response time of the system was around 1 second. It was this poor due to the voltmeter used. The sensor itself had a very low response time. If linked into a different voltmeter, or logic circuitry, the response time would no longer be a problem, as the voltmeter that causes the delay has been removed entirely. In addition, there was no drift of the readings, as long as the arm was bound well enough to the sensor, and the extreme repeatability (near zero random variation) of the sensor means it would be very reliable as the position indicator for a robotic arm. I will end on the limitations to this project. It cannot consider the effects of time and age on the sensor, its reliability under adverse conditions such as varying temperature, vibration, shock, and water resistance. It did not compare the advantages of other rotary potentiometers over this one, either. Appendix: 1. 3.14-0.35 = 2.79 2.79*100 = 279 (as the voltmeter used was accurate to 0.01 volts) 279/20 = 13.95 1/13.95 � one fourteenth 2. 180*13.95 = 2511 ?/2511 = 0.001251132 0.001251132 * 1000 * 1 � one millimetre at 1 metre ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our GCSE Systems and Control section.

Found what you're looking for?

  • Start learning 29% faster today
  • 150,000+ documents available
  • Just £6.99 a month

Not the one? Search for your essay title...
  • Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

See related essaysSee related essays

Related GCSE Systems and Control essays

  1. Building a mass balance to measure small weights (0g-100g) using a rotary potentiometer

    Then I adjusted the 1k variable till the voltmeter reads about 0V. I Created a hole in the middle of a uniform meter rule and then I fitted the rotary potentiometer tightly into the hole and hold one end of the rotary potentiometer tightly with a clamp.

  2. Bicycle Alarm Project

    one would be a waste of PCB space as well as expensive. It was therefore required to make one using logic gates. As the S and R inputs will not be selected together (this would give both Q and Q high on a simple flip-flop which is an invalid state)

  1. Design and Technology Project Design an Advertisement

    They are all also strong, the only problem I have noticed that in the workshop the wood tends to dirty easily but I think that is just down to that nature of the environment, otherwise I feel it wouldn't pick up marks too easily, so it shouldn't be too difficult to clean.

  2. Building a Sensor to Measure Weight, using a Potential Divider and Wheatstone Bridge.

    This indicates a balanced circuit, S is the fixed resistor of value 10 000 ? to make the circuit more sensitive by decreasing the voltage output, this also means the variable resistor can be changed by 1?, so the resolution is 1 ?

  1. Getting On Line Without a Computer or Internet Access at Home

    www.familyvoices.org Kids As Self-Advocates (KASA): http://www.fvkasa.org/ National Council on Disability: www.ncd.gov National Disability Specific Organizations: American Association of the Deaf-Blind: http://www.aadb.org/ The Arc (formerly Association for Retarded Citizens): http://www.thearcinc.org/ Autism Society of America: http://www.autism-society.org/site/PageServer Children & Adults with Attention Deficit Hyperactivity Disorder: http://www.chadd.org/ Epilepsy Foundation: http://www.epilepsyfoundation.org/ Federation of Families for

  2. The paper discusses the issues associated with the risks assessed between the organizations bidding ...

    and internal rate of return, profitability index, capital project (investment), Fisher's Separation Theorem, and mergers and acquisitions. These dilemmas are addressed in the numerous issues that occur within the Shang-wa Electronics, Lester Electronics, Transnational Electronics Corporation, and Avral Electronics. The NPV and internal rate of return addressed relate to the

  1. 'A small business wishes to sell a range of electronic games to help alleviate ...

    Varnish Varnish is a solution of resins in oil or spirit. It gives a hard and durable, waterproof and glossy, transparent finish. It is used as per plastic finishes but using a brush only. Paint There are so many types of paint that there is paint for every job imaginable.

  2. The aim of this investigation is to design, build and test a sensor.

    > Power Pack x 2 - In this experiment I used a separate power supply for the potential divider circuit and the light source. My reason for implementing this is that the resistance of the potential divider circuit could affect the intensity of light emitted by the bulb, thus producing unreliable results.

  • Over 160,000 pieces
    of student written work
  • Annotated by
    experienced teachers
  • Ideas and feedback to
    improve your own work