Search for JP in Topics

how to get JP-8 or diesel fuel off clothing? Answered

I got a rucksack that has JP-8 spilled on it. It wont fit in a washer and im not breaking it apart to make it fit.  Any suggestions. I have heard that coke will take it off, but i dont want it to be sticky.

Question by thematthatter    |  last reply

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Topic by JP  

Can You make High Pressure Water Washer with an Air Compressor?

Hey Guys, Any one have experience with fluids? Is it possible to build a device that would take high pressure air from an air compressor and from that make at least a mediocre respectablely powered washer? I'm thinking about buying a small air compressor and and looking to see if i can use it for other things as well. Thanks! JP

Topic by jpl500    |  last reply

Make your own Laptop Power Supply from a modded ATX (desktop) power supply

There seem to be plenty of Ebay laptops that are being sold without power supplies. I've seen a few instructables where people are taking their desktop ATX power supply and making a bench power supply. From these bench supplies people are powering electronic circuits as well as other things. SO, that being said should you be able to power laptop computers from these ATX supplies? IF so, how would you go about doing it? Thanks! JP

Topic by jpl500    |  last reply

Animal Crossing City Folk

Anybody heard of it? Animal Crossing City Folk Wii. It comes with the new Wii Speak! I dont know if its like 50 $ or 60$ Probaly around that. Well it here are it's release dates : NA November 16, 2008 JP November 20, 2008 EU December 5, 2008 AUS December 13, 2008 And it's also online and you can talk and hang out with people around the world! So who's gonna get it and whos not? RANDOMNESSSS!!!!!!!!

Topic by Owenmon    |  last reply

Any ideas for near space (weather) balloon telemetry? Answered

Hey guys, I'm considering a project like the recently popular near space balloon project. The only twist is that it could float for several days/weeks at a time. The major problem I have is that I need some way to reliably communicate with the system. The balloon would have to send climate data, gps data, and maybe photos. A video feed would be good too. I'd have to be able to control its descent and control its cameras. The issue I see is that many common systems are only good to about 40 miles which would still be way too short of a distance. Cellphones are obviously out of the question (way too unreliable up there). Satellite phones would break the bank. Power consumption is also a concern I have. I would consider getting an amateur radio license if you guys think it would help.  Note: I plan to use arduinos. JP Aerospace does some of the stuff I want to do with this potential project. The photo is their Away 46 mission.

Question by DIY Emilio    |  last reply

Best method for mounting teflon servo arms to a base (metal or wood)?

I am currently working on a simple tilt system for a mobius camera on a quadcopter. Basicly, when FPV flying, I want to be able to look directly down, and straight ahead, so I know what is below me as well as get some good footage. I have 3 parts that need to be mounted together. A small, sub-micro servo, a plastic shell/case for the mobius camera, and a fabricated piece that extends from the bottom of the quadcopter, to the servo, allowing just enough room for the servo to turn the camera ~90 degrees. I have hot glued the camera case/shell directly to the servo, so that the arm of it is free to turn directly above the center hole. The arm that mounts there then somehow needs to be mounted to a little board or something that extends down from below the quadcopter body. That piece is not difficult to mount, however, the teflon servo arm needs to firmly mount to that piece. So far I have tried hot glue (peels right off the teflon after some vibration) and universal JP weld (that grey and black stuff that takes a REALLY long time to set, and same problem). Whenever possible, I prefer to not use glue, as it is messy, sloppy and bad-looking, as well as permanent and fragile when it does work. I may sometime plan to change the design, I would prefer better mounting techniques, and do not want the bonds to break with large shock from a crash landing.

Question by -max-    |  last reply

Rockoon Project

I've seen many high altitude balloon projects and many rocketry projects on the web.  These seem to be pretty established hobbies. The I got to wondering if anyone out there had ever heard of any amateur rockoon projects? If you haven't heard of a rockoon, it is a combination of the word "rocket" and "balloon".  The concept is that a balloon is used to tow a rocket to a high altitude and then lauched. When I've searched around, most of the references I find are to the use of rockoons by Van Allen (of radiation belt fame)in the course of his research back in the 1950's.  The only thing close to anything like an amateur attempt that I found on the web was by a group called JP Aerospace back in the 90's. I'm not necessarily contemplating any such project myself, I just find it a fascinating possiblity.   And like the many amateur high altitude balloon lauches and high power rocketry, it is amazing what people put together.  I wonder if it would be feasible for a high altitude balloon plus high powered model rocket to ever technically reach the internationally recognized altitude of ~100km considered "outer space". I know that both high altitude balloons and high powered rocketry have their own FAA (or equivalent agency) approval hoops to jump through. Perhaps they just wouldn't allow it, or it would be so much red tape that no one attempts it. Even a low altitude rockoon, of a small ~3ft diameter weather balloon towing a standard model rocket would be an interesting project, for the technical challenge of pulling it off successfully. Anyway, if anyone has ever heard of amateur rockoon attempts or your own musings on the topic, I'd be interested in hearing about it!

Topic by LargeMouthBass    |  last reply

Construction ideas for this concept?

Recently, I have been working on a gas 'vaporizer' that evaporates gas before being fed into an engine. During my short-term experiment, I found that this saves ~70% (+-20% for crudity of measurement.) This works because the vapors will burn more thoroughly and cleanly, leading to higher apparent efficiency. Below is a basic diagram of how the system works. You can see there is a container that is half-full with gas, and a hose goes down with many small holes. As the engine's compression draws a vacuum on the container, air will come up through the holes. As it rises, the gas-air surface area rises dramatically, leading to the vaporization of gas. To further increase the surface area, I also added a felt liner on the inside to allow the gas liquid to rise and evaporate. The final mixture ends up very rich, so to compensate, a 'T' fitting has been added to allow air to mix in with the vapors/fumes. Some valves have also been added to control the air inlet (similar to a 'choke') and the amount fed to the engine (similar to a throttle. In fact, it is possible to use the original throttle or choke as a throttle on the carburetor on my tractor!) The problem is: My original design utilized a plastic folgers coffee can, and the flimsy plastic top was hot glued to a thicker plastic cutout for strength and support. Since most glues will dissolve in gasoline, including hot glue, it could not be used. most did not hold anyway. I also tried JP weld plastic cement and it did not hold at all. I had to trash this build. I did, however, get enough use to run the tractor for several minutes while testing gas use. I found that the tractor used nearly twice as much simply running on gas than the fumes. I did not have the float valve and electric pump hooked up with the prototype. Also the 3/4in housing I used may be a bit constrictive and also seems to get slightly damaged by the gas. It will not be a long-term solution.  So I need to redesign the project, and I am thinking of using a 1-3 gallon bucket that is sealed or a gas tank. I need good almost air-tight seals on everything. I am asking for any ideas related to the construction of this device and any tips you may have.

Question by -max-    |  last reply

How can i combine these 3 codes?i'm completely new to arduino ?

Code 1: Ultrasonic sensor and LCD I2C Display #include #include #include #include #define I2C_ADDR 0x3F // <<- Add your address here. #define Rs_pin 0 #define Rw_pin 1 #define En_pin 2 #define BACKLIGHT_PIN 3 #define D4_pin 4 #define D5_pin 5 #define D6_pin 6 #define D7_pin 7 #define ECHO_PIN 11 // Arduino pin tied to echo pin on the ultrasonic sensor. #define TRIGGER_PIN 12 // Arduino pin tied to trigger pin on the ultrasonic sensor. #define MAX_DISTANCE 500 // Maximum distance we want to ping for (in centimeters). Maximum sensor distance is rated at 400-500cm. NewPing sonar(TRIGGER_PIN, ECHO_PIN, MAX_DISTANCE); // NewPing setup of pins and maximum distance. LiquidCrystal_I2C lcd(I2C_ADDR,En_pin,Rw_pin,Rs_pin,D4_pin,D5_pin,D6_pin,D7_pin); void setup() { lcd.begin (16,2); // <<-- our LCD is a 20x4, change for your LCD if needed // LCD Backlight ON lcd.setBacklightPin(BACKLIGHT_PIN,POSITIVE); lcd.setBacklight(HIGH); lcd.home (); // go home on LCD lcd.print("Obst. distance"); } void loop() { unsigned int uS =; // Send ping, get ping time in microseconds (uS). unsigned int cm = sonar.convert_cm(uS); // Convert into centimeters lcd.setCursor (0,1); // go to start of 2nd line lcd.print(" Distance:"); lcd.setCursor (0,3); // go to start of 4th line lcd.print(": "); lcd.print(cm); lcd.print(" cm "); delay(500); } code 2: PIR sensor with buzzer // Uses a PIR sensor to detect movement, buzzes a buzzer // more info here: // email me, John Park, at // based upon: // PIR sensor tester by Limor Fried of Adafruit // tone code by int ledPin = 13;                // choose the pin for the LED int inputPin = 2;               // choose the input pin (for PIR sensor) int pirState = LOW;             // we start, assuming no motion detected int val = 0;                    // variable for reading the pin status int pinSpeaker = 10;           //Set up a speaker on a PWM pin (digital 9, 10, or 11) void setup() {   pinMode(ledPin, OUTPUT);      // declare LED as output   pinMode(inputPin, INPUT);     // declare sensor as input   pinMode(pinSpeaker, OUTPUT);   Serial.begin(9600); } void loop(){   val = digitalRead(inputPin);  // read input value   if (val == HIGH) {            // check if the input is HIGH     digitalWrite(ledPin, HIGH);  // turn LED ON     playTone(300, 160);     delay(150);        if (pirState == LOW) {       // we have just turned on       Serial.println("Motion detected!");       // We only want to print on the output change, not state       pirState = HIGH;     }   } else {       digitalWrite(ledPin, LOW); // turn LED OFF       playTone(0, 0);       delay(300);         if (pirState == HIGH){       // we have just turned off       Serial.println("Motion ended!");       // We only want to print on the output change, not state       pirState = LOW;     }   } } // duration in mSecs, frequency in hertz void playTone(long duration, int freq) {     duration *= 1000;     int period = (1.0 / freq) * 1000000;     long elapsed_time = 0;     while (elapsed_time < duration) {         digitalWrite(pinSpeaker,HIGH);         delayMicroseconds(period / 2);         digitalWrite(pinSpeaker, LOW);         delayMicroseconds(period / 2);         elapsed_time += (period);     } } CODE 3: MQ5 LPG gas sensor int sensor=7; int gas_value; void setup() { pinMode(sensor,INPUT); Serial.begin(9600); } void loop() { gas_value=digitalRead(sensor); Serial.println(gas_value); }

Question by aaryank4    |  last reply

I need help coding an arduino sketch to activate audio from an mp3 board when my PIR senses motion

My goal is to have a sound effect play when a person first walks into the field of view of my PIR. So far I can get it to work, but the sound "stutters" for about 4 seconds before it will play through all the way. The parts that I am using are: (this board doesn't have a datasheet, so i have been using the 'old version' datasheet: ) and an arduino uno besides vcc and ground, my arduino's pins connect pin7 to my mp3 board's number 1 pin (which is active low) and also from my arduino's pin3 to the out/signal from my PIR sensor. I have tried a couple different example sketches and modified them to something that i thought would work, but they both have similar problems with "stuttering". Below are the sketches after modification. (note: I haven't finished changing some of the commenting yet.) I would be very thankful for any and all help. I can admit, I'm not very good at this kind of thing. This project is for halloween in 2016. I'm so bad (and I realize it) that I'm starting a year in advance. FIRST SKETCH: // Uses a PIR sensor to detect movement, buzzes a buzzer // more info here: // email me, John Park, at // based upon: // PIR sensor tester by Limor Fried of Adafruit // tone code by int MP3Song1Pin = 7;                // choose the pin for the mp3 board int inputPin = 3;               // choose the input pin (for PIR sensor) int pirState = LOW;             // we start, assuming no motion detected int val = 0;                    // variable for reading the pin status void setup() {   pinMode(MP3Song1Pin, OUTPUT);      // declare mp3 board as output   pinMode(inputPin, INPUT);     // declare sensor as input   Serial.begin(9600); } void loop(){   val = digitalRead(inputPin);  // read input value   if (val == HIGH) {            // check if the input is HIGH     digitalWrite(MP3Song1Pin, LOW);  // turn mp3 board on     delay(10);     digitalWrite(MP3Song1Pin, HIGH);  // turn mp3 board         if (pirState == LOW) {       // we have just turned on       Serial.println("Motion detected!");       // We only want to print on the output change, not state       pirState = HIGH;     }   } else {       digitalWrite(MP3Song1Pin, HIGH); // turn mp3 board OFF       if (pirState == HIGH){       // we have just turned off       Serial.println("Motion ended!");       // We only want to print on the output change, not state       pirState = LOW;     }   } } SECOND SKETCH: /* * ////////////////////////////////////////////////// * //making sense of the Parallax PIR sensor's output * ////////////////////////////////////////////////// * * Switches a LED according to the state of the sensors output pin. * Determines the beginning and end of continuous motion sequences. * * @author: Kristian Gohlke / krigoo (_) gmail (_) com / * @date:   3. September 2006 * * kr1 (cleft) 2006 * released under a creative commons "Attribution-NonCommercial-ShareAlike 2.0" license * * * * The Parallax PIR Sensor is an easy to use digital infrared motion sensor module. * ( * * The sensor's output pin goes to HIGH if motion is present. * However, even if motion is present it goes to LOW from time to time, * which might give the impression no motion is present. * This program deals with this issue by ignoring LOW-phases shorter than a given time, * assuming continuous motion is present during these phases. *  */ ///////////////////////////// //VARS //the time we give the sensor to calibrate (10-60 secs according to the datasheet) int calibrationTime = 30;        //the time when the sensor outputs a low impulse long unsigned int lowIn;         //the amount of milliseconds the sensor has to be low //before we assume all motion has stopped long unsigned int pause = 5000;  boolean lockLow = true; boolean takeLowTime;  int pirPin = 3;    //the digital pin connected to the PIR sensor's output int ledPin = 7; ///////////////////////////// //SETUP void setup(){   Serial.begin(9600);   pinMode(pirPin, INPUT);   pinMode(ledPin, OUTPUT);   digitalWrite(pirPin, LOW);   //give the sensor some time to calibrate   Serial.print("calibrating sensor ");     for(int i = 0; i < calibrationTime; i++){       Serial.print(".");       delay(1000);       }     Serial.println(" done");     Serial.println("SENSOR ACTIVE");     delay(50);   } //////////////////////////// //LOOP void loop(){      if(digitalRead(pirPin) == HIGH){        digitalWrite(ledPin, LOW);   //the led visualizes the sensors output pin state        delay(50);        digitalWrite(ledPin, HIGH);        if(lockLow){           //makes sure we wait for a transition to LOW before any further output is made:          lockLow = false;                     Serial.println("---");          Serial.print("motion detected at ");          Serial.print(millis()/1000);          Serial.println(" sec");          delay(50);          }                  takeLowTime = true;        }      if(digitalRead(pirPin) == LOW){              digitalWrite(ledPin, HIGH);  //the led visualizes the sensors output pin state        if(takeLowTime){         lowIn = millis();          //save the time of the transition from high to LOW         takeLowTime = false;       //make sure this is only done at the start of a LOW phase         }        //if the sensor is low for more than the given pause,        //we assume that no more motion is going to happen        if(!lockLow && millis() - lowIn > pause){             //makes sure this block of code is only executed again after            //a new motion sequence has been detected            lockLow = true;                                   Serial.print("motion ended at ");      //output            Serial.print((millis() - pause)/1000);            Serial.println(" sec");            delay(50);            }        }   }

Question by Zukibeast  

Solar Power Towers Efficiently Using Brayton Cycle

I want to point out a solar to electric generation concept that has yet to be seen anywhere, even though it originated back during the Carter Administration's ERDA programs of the late 70's. I’m talking about solar power towers that convert solar energy into electricity at the hundreds of mega-watt level. While power towers do exist today, and the world currently does have a handful of them as shown in Fig-1, none use the Brayton Cycle nor can they boast an energy conversion efficiency at the mid to upper thirty percent level.  A group of engineers got together at a think tank organization called Sanders Associates in Nashua, N.H., several decades ago, and designed a unique Brayton Cycle, 100 MW solar Power Tower concept for generating electricity. This was accomplished under ERDA (Energy Research Development Administration) who gave us a phase-2 follow-up contract that took our phase-1 design and built a working scale model at the 10 KW level. This model was tested at the Georgia Tech Solar Research Facility and "registered" ~37% electric solar conversion efficiency. The system used ambient air as its working fluid, and was to be located in open-spaced desert regions. Phase-2 was lost to competition using a closed-loop liquid sodium system that boiled water into superheated steam at 900F to run a turbine that generated ~21% overall electric conversion efficiency.  Apparently, at that time ERDA would rather haul water out to the desert than use ambient air to generate electricity? The politics of their decision is beyond reason and clashes with improving the world’s development of green technology energy.  ERDA shut out our better technological performer and safely locked it away for another day! ERDA's official reason for turning us down: "this technology uses excessively high temperatures (2500F versus 900F) that are dangerous to workman maintaining the equipment". But that was back in the 70’s, maybe we’ve learned to deal with high-temp heat by now?   Solar Energy Concept Using Low Pressure Storage Our solar power tower would collect the sun’s energy by locating its ceramic heat exchanger on top of a tall tower as shown in Fig-1. The tower was located in the center of a field of active sun-searching mirrors (heliostats, Figure-2). These mirrors reflected sunlight onto our ceramic honeycomb heat exchanger, producing a concentrated flux intensity level that heated it to around 2500F. At the same time, low pressure fans generating only a few psi pressure would suck the ambient air through the honeycomb, heating it to just under the 2500F and then passing it through energy storage silos which stored the heat down to ~150F. We purposely designed the energy storage charging phase of our hot air system to work at only a few psi above ambient as a safety feature. The sun effectively acts as the combustor of our jet engine or Brayton cycle engine. Once the sun heats the air, it passes through heat exchangers consisting of a labyrinth of underground silos that are temperature segregated. These silos receive our 2300F airflow and cool it down to about 150F, transferring this heat into solid salt containers which turn to liquid once they have absorbed sufficient heat. Figure-3 is a schematic of this underground energy storage facility and shows the airflow being heated by a fully charged set of silos containing liquid salt-bricks. This airflow direction is reversed when we charge the silo’s salt-bricks. The bricks are kept in specially insulated, high pressure silos (located underground for added insulation) that store the heat energy at one atmosphere for later use. These underground silos act as our energy storage batteries, and when needed would discharge their heat energy accordingly into the moving airflow. This energy storage concept permitted the generation of electricity at night and during overcast days. Two sets of storage systems are required for continuous operation. One would be charging at low pressure while the other is discharging at high pressure through the Brayton engine to generate electricity.   Electric Energy Generation at High Pressure Electricity would be created by turning an electric generator at high speed. The generator was turned by running a jet engine connected to it.  The engine’s combustor for heating the air is effectively the sun, hence the name Brayton cycle for generating our solar electricity (Figure-4). The heat from the molten salt containers would increase the energy of the high pressure air coming from the compressor, and would then force it through a typical turbine that turns this energy into high rotational speed to run the generator and make electricity. Our solar jet engine sucks in ambient air using its compressor, as all jet engines do, and blows it through a series of silos at high pressure whose stacked bricks are held at different temperature levels. We start our airflow through a silo held as low as 150F and work our way up to ~2300F as we pass through our last, hottest silo which acts to complete the effective solar combustion process. This air preheating technique dramatically improves our energy turnover capability and allowed us to convert solar energy into electricity at near 37% efficiency. During our electric energy generation phase, the silos of our Brayton system requires operating at many atmospheres of pressure just as in any jet engine combustor using petroleum-based JP-fuel.      

Topic by RT-101    |  last reply