Unanswered Questions

13
votes
1answer
491 views

What does a “sad face with a bow tie” represent?

Some trains in the Madrid metro network have small metal boxes with this sign on them: There are no other signs on the box and some signs only have the "bow tie". I'm guessing it's two Zener ...
8
votes
0answers
148 views

Antenna matching network topology

In tuning an antenna, there are multiple possible topologies that will take it to the middle of the smith chart. Some differences that I can see between them are: Component ESR (losses). Effect ...
6
votes
0answers
288 views

Unable to get bootloader working on custom PCB with AT32UC3L

I have designed a PCB for a client recently, everything is fine with the hardware and software (application is working as it is supposed to). Now we are facing the need to update the program inside ...
5
votes
2answers
374 views

Safe shutdown/restart Raspberry Pi due to a power loss

I am a total beginner in electronics so I need your advice. Does this simple circuit provide for a safe shutdown, with two super caps of 10F? (Original image)
5
votes
0answers
123 views

Implementation of AES algorithm using Systolic architecture

I need to generate a VLSI Systolic array to implement the AES encryption algorithm with key length of 128 bits. Following are the possible ways : Systolic for Key expansion Systolic in MixColumn ...
4
votes
0answers
33 views

Designing an optimal BPSK and/or QPSK transciever in SDR

I'm currently working on writing firmware for the modem on a cube satellite for my university's satellite team. My primary goal is to implement the data uplink & downlink. The RF system, ...
4
votes
1answer
97 views

Is there any pattern or standard to through-hole resistor sizes?

I've long been under the impression that a quarter-watt resistor has a standard package, and a half-watt resistor has a standard package, etc. But I've recently gotten through-hole resistors which are ...
4
votes
1answer
44 views

How appropriate are the open source licences currently in use for inclusion of HDL cores in a commercial product?

HDL IP cores targeted towards ASICs, FPGAs or both are often very useful for adding functionality to a project quickly. Commercially licences cores are available from many sources for a range of ...
4
votes
0answers
109 views

History of the MSP430

This question crossed my mind today. What is the history of the MSP430? When did it start, what did it evolve from, why was it made (i.e. what goals was it trying to achieve/what technical ...
4
votes
2answers
176 views

How to convert files from Cadence to Eagle CAD?

Is there any free software that can convert Cadence files (.dsn, .opj, .brd) into Eagle CAD files (.brd, .sch)?
4
votes
2answers
163 views

Stuck codes in samples from ADC

I am currently testing a 16-bit DAC and a 18-bit ADC. In many tests I have found the ADC to get "stuck" at codes, especially at the ends of the input range. Both the DAC and ADC operate in bipolar ...
4
votes
0answers
246 views

AHRS algorithm under continuous linear accelerations

I have tried several algorithms to get pitch, roll and yaw under continuous linear accelerations and vibrations (smaller than 0.4g, frequency lower than 10HZ). None of them give good results because ...
4
votes
1answer
219 views

Difference between virtual and ground plane

Ive created two PCBs, a power board to output a +-5V supply and a midway voltage reference (using the TLE2426) at 0V. This PCB powers a biosignal acquistion board shown in the spice diagram below. ...
4
votes
3answers
703 views

DIY NFC boosting antenna for a mobile device

I am very new to this. I'm a dentist trying to improve client flow in a busy office. I would like to develop a cheap proof of concept for an NFC enabled client tracking system using a hacked mobile ...
4
votes
1answer
225 views

Miniature wireless distance sensor

I am novice in electronics, so please bear with me. I am searching for a small distance sensor (as small as possible) that I can use to measure a distance between 0 and 30 cm precisely (precision ...

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