Sensors convert a physical quantity (e.g. temperature, pressure) into an electrical signal.
0
votes
0answers
5 views
AXDL345 Accelerometer on SPI Raspberry PI with bcm2835
I have this accelerometer ADXL345. I am trying to read data from it from SPI using the BCM2835 Library here.
When I run this, I SOMETIMES get a value back (other than zero), but it's never ...
0
votes
1answer
38 views
How to build a simple body conductivity sensor?
I want to build a device, which measures several body parameters (pulse, body conductivity) and sends them to a mobile device.
I found a cheap pulse sensor and now I'm looking for the body ...
2
votes
2answers
92 views
Problem of noisy ground
In this design, the 2A motor "M", which is running at PWM=10kHz, creates a lot of noise in the ground as shown on the scope trace. Not only the ground is sinusoidal but more painful, the ground level ...
-1
votes
0answers
41 views
very precise altimeter and / or x/y/z location transmitter [closed]
are there any very cheap and very small (not larger than 4x4 inches) gadgets that i can buy that can roam around on their own on a flat surface and transmit their location, and elevation (precise to ...
2
votes
2answers
56 views
Mini Skee Ball - Detecting a ping pong ball
Background
I really want to do something with my raspberry pi, so I thought of a game that's a mix between skee ball and beer pong. Basically, the build is a mini skee ball board (about 20x24 ...
3
votes
1answer
47 views
Strange and contradictory AGC characteristics in datasheet
I am trying to select an IR receiver for a remote controlled unit, from this table. Here is one example, but all of the parts exhibit the same seemingly contradictory specification.
Having a look ...
3
votes
1answer
65 views
Making a electrical signal detector (Inputs from multiple source)
I am working on an electrical project that, actually works something like a touchscreen digitizer, where I have to generate multiple inputs from over 50-100 sources, and I need to check from which ...
1
vote
0answers
28 views
IOIO-OTG, PIR sensor and Bluetooth Interference
I have built a sensor motion device that is battery operated and sits in a small box. Its purpose to detect wildlife movement. The setup is as follows:
IOIO-OTG connected to a PIR ...
4
votes
3answers
115 views
Vehicle buttocks detection
In my truck a warning light comes on when I go to take off if a passenger is sitting there but the seatbelt is not secured. After some research and thinking it may be their weight, capacitance or ...
3
votes
2answers
83 views
A heat sensor that powers an LED with no controller
I'm a programmer, and I can wrap my head around having a controller board which monitors a temperature sensor llike this ...
1
vote
1answer
50 views
OneWire DS18B20 on mighty 1284p can't find my sensors, same sensors work w/ Duemilanove
I have uploaded the DS18x20 Temperature example sketch (unaltered, except I tried multiple pins for the I2C communication) to my proven Duemilanove and my ...
6
votes
1answer
110 views
How can I use a generic doorknob as a capacitive touch sensor?
I would like to use a generic doorknob that's installed in a typical wooden exterior door as a capacitive touch sensor. I have found various references for the circuit, but I have some questions about ...
2
votes
2answers
92 views
How to connect sensors to an Android device?
I need to build a device, which measures several parameters (body temperature, conductivity and pulse) and transmits them to an Android mobile device.
The system has following parts:
The sensors
...
2
votes
2answers
151 views
Expanding Range Of Analog Values From Temperature Sensor
I'm trying to build a temperature controlled relay module with an ATtiny45 ( Arduino UNO R3 as ISP ) and a NXP KTY81-222 Temperature Sensor.
The temperature range i want to monitor is 20°C to 30°C.
...
3
votes
0answers
73 views
Charge mode piezoelectric signal conditioning
I have a charge-mode piezoelectric dynamic pressure sensor (datasheet link) that I want to read a signal from. If you look at the datasheet it says the sensor outputs are in a balanced and floating ...
1
vote
0answers
64 views
Sensing pressure from 4 tanks, using 1 pressure sensor [closed]
I'm tryng to read from 4 water tanks pressure/level, each containing max 10liters.
For this goal and for minimizing the costs, I was planning to use:
1 pressure sensor (5V, digital or analog, ...
-1
votes
1answer
45 views
interfacing a transducer to a pic16f877a
I have a pressure transducer with an out put of 4-20mA and having problems in interfaceing it with a pic16f877a micro-controller
4
votes
4answers
222 views
Ideas for a cheap, simple, common temperature sensing component?
I'm looking to make a device to regulate a heater to maintain 100-110 degrees Fahrenheit in a small, moderately insulated container. Specifically, I'm wondering what I might have in my parts drawer ...
3
votes
2answers
78 views
Heat Activated Alarm
I am working on a project in which I have to simulate a heat activated alarm. I have attached two images. One of which is a Proteus circuit image that i have made. When i start its simulation the ...
2
votes
1answer
80 views
Reversing a .5-4.5V analog sensor output to 5V-0V
I have a pulse width modulation (PWM) control board that uses a 0-5V input via a potentiometer to control a DC motor speed. As I understand how this works, the potentiometer goes from 0% PWM at 0V to ...
-2
votes
0answers
39 views
looking for philips humidity sensor eagle .lib file [closed]
I'm working on my first eagle project, I want to use the philips humidity sensor 2322 691 90001.
http://www2.informatik.hu-berlin.de/~hochmuth/bvp/humidity.pdf
My problem is that I can't find this ...
1
vote
1answer
49 views
MQ137 Ammonia sensor - Pins not labeled
I recently purchased an MQ137 Ammonia sensor and breakout board. Unfortunately the item came with the two parts separated with no markings as to the orientation. Can anyone advise on the pin layout?
...
1
vote
1answer
69 views
Suggest some methods for measuring AC current
I need to find a method of doing so without consuming much space in PCB like in the case of current transformers. The circuit must be able to measure upto 15A of AC current(RMS).
0
votes
1answer
82 views
Interference beetween ADC samples with XBee and photoresistor
I'm using an XBee serie 2 module for sampling the values of three sensors, a photoresistor (LDR) a moisture sensor and a temperature sensor (LM35). When there is no brightness the photoresistor has ...
0
votes
0answers
63 views
Arduino Compatible CO2 Sensor [closed]
I am looking for a relativity inexpensive CO2 sensor that will work easily with an Arduino. I have done some research and only found one real option, and it looks like some sort of an amplifier will ...
2
votes
2answers
140 views
The influence of a potentiometer on photo-diode bias
I have a sensor which I have connected to an Arduino via SerialPort to get data readings.
There is a "screw potentiometer" (It's a screw that changes resistance which affects the output voltage).
If ...
3
votes
1answer
105 views
Temperature current source using a LM35
Anyone care to explain how this piece of circuit work?
I already build it and it works wonders but I can't figure it out.
0
votes
3answers
123 views
Modifying a digital LED thermometer kit to drive larger 4" 7-segment LEDs?
I'm interested in building an LED digital thermometer with 3 or 4 large 4"/100mm 7-segment LED display digits (for example, Kingbright SA40-19EWA). There are plenty of kits available which come with ...
8
votes
2answers
242 views
Collimating a sonar beam
Wondering if anyone is aware of a way to cause an ultrasonic proximity sensor to be modded, such that, it's forward line-of-sight range remains unaffected, but it's angular spread is reduced, somewhat ...
7
votes
3answers
303 views
Circuit works on breadboard but not PCB
I have a fairly simple circuit that works perfectly on the breadboard, but I am having a lot of trouble transferring it to a PCB. I am seeing very strange behavior which lies outside of my current ...
0
votes
1answer
320 views
Water level: BIG capacitive level sensor with steel bars?
So I want to measure water level under a bridge, or inside the city drain.
Would it be possible to run two long (4 meter) metal probes, each one enclosed inside a PVC pipe, and placed one next to the ...
1
vote
2answers
71 views
Recommended Sensor? Distance - High Heat & Dusty
I'm after a sensor and I'm wondering what would be the best type for the following.
Requirements -
Accurately measure in the 5-10mm distance range, +/- 1mm.
Sense small undulations in a surface ...
2
votes
1answer
107 views
Can I electronically trigger a PIR motion sensor?
I would like to trigger a PIR sensor using an infrared LED. Is that possible? My goal is to simulate motion in front of the PIR, when there otherwise is none. I tried using a handheld remote ...
1
vote
2answers
63 views
How can I make a motor stop when the output of a PIR sensor is below a threshold?
I will attach a PIR sensor to a motor and i want the motor to stop turning when the output of the PIR sensor ( http://www.rapidonline.com/pdf/61-1466.pdf ) is below a threshold. I also want the motor ...
4
votes
3answers
143 views
Is the Excitation Voltage of a load cell a strict specification?
When using load cells (or strain gages generically), is the Excitation Voltage spec provided as a strict minimum -- or is it just a recommendation which one can go below as long as one is OK with a ...
1
vote
2answers
95 views
Is is possible to produce a resistance that represents the average of two thermistors?
For example, if I want to connect 2 thermistors to a thermostat in a circuit and then return the average resistance between the two of them to the thermostat's ADC.
-1
votes
3answers
99 views
No previous knowledge of programming, considering electrical engineering [closed]
I am still at school and wont finish until 2015 but i have seen people control doors, toy cars etc with their iphones and i really want to get in to something like that.
I have a lot of spare time ...
-1
votes
3answers
145 views
tiny dtmf dialler [closed]
I would like to create a small dtmf dialler that connects to a telephone line and dials a single preprogrammed telephone number when a set of contacts closes, how easy is this and how small could this ...
2
votes
3answers
82 views
Wireless communications for distance estimation (RFID perhaps?)
What I want to do it is measure the distance between two points/ devices which are constantly moving apart or together. The value for distance isn't really required I'd just be looking to have an ...
2
votes
3answers
170 views
Simplest touch sensor for a copper surface
I'm looking for the simplest way to implement a binary on|off touch switch using a single pole. The touch surface is copper. The position or pressure of the touch is not needed, just simply:
On = ...
0
votes
3answers
117 views
A device that wirelessly, securely posts to a server in response to door opening: off the shelf or custom-make?
I am looking for an off the shelf component for a project I am currently working on. Due to the nature of the project I cannot go into much detail about the project itself, only give a high level ...
0
votes
2answers
167 views
I2C temp sensor and an Arduino wifi shield not working together
I am using an arduino wifi shield and a TMP102 with an arduino uno rev2.
With boards older than rev3 you have to add a jumper from the 3.3V to the IOREF pin for the wifi shield, see here: ...
4
votes
4answers
155 views
devices for measuring tension or detecting “slackness” in fishing wire
How might I go about measuring the tension in a line of fishing wire? I'm mostly interested in determining when the line is in tension vs when it's slack.
The application is a boat-mounted ...
4
votes
2answers
68 views
Xbee to act as wireless i/o extension
I want to have an arduino with an xbee (call it xbee1) connected to it and another wireless xbee (call it xbee2) communicating with xbee1. Then I would have DIO1 on xbee2 acting as a digital input and ...
0
votes
0answers
43 views
Arduino sensors for x10
I am wiling to begin my ride in home automation.
I realy want the Insteon ISY controller(that is x10 compatible) and some x10 2-way micromodules. But the project is realy complex and I need some ...
0
votes
2answers
762 views
Arduino controlled PWM PC Fan
I am looking at getting 2 Evercool EC8015HH12BP 80x10mm (4-wire) PWM fans. However, i am looking at controlling the fan speed with the arduino via the PWM pins.
I found the following diagram that ...
0
votes
0answers
102 views
Sensing salt concentration in air
I need to measure salt concentration in air (coastal). Any ideas how?
I would prefer to have result real time and it can be up to USD 2000.
5
votes
2answers
187 views
How to process voice commands using ATmega or Arduino?
For a project I need to start my PC using voice command. I thought to made up an voice controlled system to turn on my PC. As far as I know, when I press the turn on button-2 pin's on the motherboard ...
3
votes
3answers
123 views
Vibration Detection bronze keyed instrument
I want to be able to detect when a bronze key (Balinese Gamelan) gets struck by a mallet (hard wood) without effecting the keys vibration, so a piezo is likely out.
Example of the instrument:
Is ...
1
vote
1answer
62 views
How do I know what the right signal amplifier to use is in order to program a hall-effect sensor?
I am trying to look for a signal amplifier in order to program the sensitivity and offset of the A1362 Hall-Effect sensor.
Doing a simple google search reveals:
...
