The Engineering Projects

What are the components required for a paper circuit for transmitting data to android mobile?

Basically I am a software developer and I am new to electronics. Consider that a paper have different touch points drawn with a graphite / pencil and I would like to transmit the touch points' codes / values to an android mobile application. And I have an android app which runs a thread with a timer. I need to match the exact time position in a thread and touch time on my paper circuit.

I need to know the basic components required to collect different code values of each touch point in my paper circuit and transmit the value to the android application instantly where my application can compare whether the user action is matched with the automated timer logic.

I simply tried a paper circuit by lighting an LED with a power supply by referring this video link Also this video too. If possible I can use wifi to transmit the value to my android app. Few of my friends suggested to use Bluetooth. I need to know first whether on touch we can enable some point in a pcb circuit to transmit some defined code value. (pls see the video)

Also I would like to know how the keys in that DIY paper circuit midi keyboard works? how the program captures each key and play different sounds accordingly?


Kindly suggest your ideas. If anyone can provide some basic circuit examples I will be more grateful.

Need to know if this freq Gen will give me a 2100Hz signal over a 25MHz carrier

25MHz Dual-channel DDS Arbitrary Waveform Function Signal Generator Specs are:
Frequency Range Sine Wave
Normal Modes: 0.01Hz~25MHz

Square Wave 0.01Hz~6MHz
Triangle Wave 0.01Hz~6MHz
Sawtooth Wave 0.01Hz~6MHz
Arbitrary Waveform 0.01Hz~6MHz
TTL Digital Signal Wave 0.01Hz~6MHz I'm using it on a old tube type 300 watt single channel ham Linear Amp

Diode help

Hi all new here so please be gentle. I have a Polaroid led tv I'll spare you all the boring details but after some Internet research I found a problematic diode in the TV. Main question is about the numbers on these diodes as I have a few old electronic boards lay about in the shed so replaced that diode with one I found in another board the diode out the TV is numbered UF5404 I firstly replaced it with SB560 still didn't work although that diode was fine so replaced again with IN5408 tv now powers up but turns off after around 10 seconds. Does that diode have to be replaced with the exact same diode or could I use another one. Sorry if this sounds like a silly question just thought as the TV is already broke I may as well have a try. Thanks for reading.

Aerial (roof) rotating antenna operation?

The particular case here is one of those systems where you have a light antenna on the roof, a little box inside controlled by a remote control for rotating clockwise or counterclochwise and the antenna connection and box is through a single coaxial cable.

My questions are:
1) is the box sending a decodifiable signal through the coaxial cable or,
2) is it a wireless communication that exists between the box and the antenna motor?

In the case it's through the coaxial cable, if the controller box (the one at the living room) is damaged but the motor is working ok, how can I control the motor (forward/reverse) even if I've to use another pair of cables for the purpose?

Thanks in advanced for any help on this!

Power output from a mobile phone aux socket

Obviously it has a sufficient output to drive ear buds, but just how large a speaker would it drive? I like the idea of extension speakers but find the quality of bluetooth audio garbage so "hard wired" is the preferred option for me and if I can get away without a built in amp that would be great

Transistor Help

Hi guys,

I do not have a whole lot of knowledge concerning electronics so I am turning to the forums for information.
In my circuit I want to control a servo motor. But I only want to power this servo when I am using it.
Here comes the transistor in the picture. With a USB supplying 5V to the collector of the transistor, and a raspberry Pi supplying 2.5V to the Base. I thought the Emitter would pass through about 5V, but it is only passing 2V.

I need to power my server with roughly 5V and be able to control the power to this circuit with my Raspberry Pi.

Is this the right approach? What am I doing wrong

Thanks in advance for your help

Newbie Question: 12v led ?push button latching switch

I have a 12v led push button switch that I want to function like a regular push button that does not use any power, i.e. No led. I want to use the led, but when pushed I do not want to send power over the load, just close conductivity like a regular push button.

So, is there a way to drop the 12v that would normally be sent over the load to basically zero?

Thanks

How do constant current loads work and how to make one

Hi, I'm not the best at understanding electronics, how does a constant current load work and how can i make one, and what makes them have limits before they get fried?

Physical size of cap's

I have a cap on a board that is 405v 47uf 105'c and is 50mm long by 10mm (2" x 3/8").
Can I replace it with a cap of the same value but physically smaller ? Half the size.
It is in a switch mode psu.

window comparator help

I'm struggling on window comparator circuits.

I'm trying to build a game circuit that uses 6 wires. Each wire must go from point A to point B, C to D, E to F, ect. and only that wire can go in that relationship so if A to C nothing happens.

I thought a window comparator would have been the trick to make this work. using a voltage split and a lm324 but I can't get the lm324 to work properly. If anyone is interested I'm game for some assistance.