Tried simple microcontroller adc and mic peak level but it detect all sounds no discrimination between human and external sounds like TV, or other machines.
Looking for Recommendations – Practical Postgraduate Courses
I’m looking at postgraduate courses that are more practical and hands-on, rather than mainly theory-based.
Ideally, I’m looking for a course that combines:
\- Power systems and the electrical grid
\- Solar and other renewable energy sources
\- Inverters, batteries and energy storage
\- Data-centre electrical power systems
\- Electronics design and practical electronics.
If you have studied, worked in, or have experience with universities in these areas, I’d really appreciate your recommendations.
I’m more interested in real-world practical exposure and industry relevance than just the course title or university
I’m looking at postgraduate courses that are more practical and hands-on, rather than mainly theory-based.
Ideally, I’m looking for a course that combines:
- Power systems and the electrical grid
- Solar and other renewable energy sources
- Inverters, batteries and energy storage
- Data-centre electrical power systems
- Electronics design and practical electronics
Any suggestions.
am a beginner and want to build a simple spread-spectrum communication experiment using a 555 timer and microcontroller
My idea is to use the 555 as a carrier clock, use the Arduino to generate a pseudo-random (PN) sequence and XOR it with the data, then transmit the signal over a 12 V two-wire line.
At the receiver, I want to recover the carrier/timing and use the same PN sequence to despread the signal and recover the original data.
Is this a reasonable way to demonstrate the basic principle of DSSS? What would be the simplest circuit architecture for a beginner?
am a beginner and want to build a simple spread-spectrum communication experiment using a 555 timer and microcontroller
My idea is to use the 555 as a carrier clock, use the Arduino to generate a pseudo-random (PN) sequence and XOR it with the data, then transmit the signal over a 12 V two-wire line.
At the receiver, I want to recover the carrier/timing and use the same PN sequence to despread the signal and recover the original data.
Is this a reasonable way to demonstrate the basic principle of DSSS? What would be the simplest circuit architecture for a beginner?
When your mind starts saying things like:
\- “What if I had chosen differently?”
\- “I could have done this instead.”
\- “I would have been happier if I had taken that opportunity.”
\- “What if things had worked out another way?”
What is the counter-question you ask yourself to stop the endless hypothetical “what if” loop?
What’s your go-to question?
When your mind starts saying things like:
- “What if I had chosen differently?”
- “I could have done this instead.”
- “I would have been happier if I had taken that opportunity.”
- “What if things had worked out another way?”
What is the counter-question you ask yourself to stop the endless hypothetical “what if” loop?
What’s your go-to question?
1: Does neutral being grounded give the device any extra way to turn off, or does it just act as a normal low-impedance return path for fault current?
Trying to figure out if a zero-cross detector referenced to earth could give a false "off" reading. Anyone dealt with this?
Looking for simple things you genuinely enjoy doing when you have free time—hobbies, creative activities, learning, exercise, exploring, or anything else.
I have a solenoid coil connected in series with the load. If the coil develops shorted turns and its inductance decreases, what's the simplest and cheapest way to detect it using a microcontroller or a simple analog circuit?
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I'm trying to understand how releasing circuits supervise solenoid valves.
In many gas suppression systems, the solenoid is wired in series with an end-of-line (EOL) resistor. I understand that the panel can detect open circuits and wiring shorts.
However, what happens if the solenoid coil itself develops an internal short (for example, shorted turns that reduce the coil resistance but don't create an open circuit)?
- Will the releasing panel detect this as a fault?
- Or does the EOL resistor only supervise the field wiring, with internal solenoid failures managed through periodic inspection and maintenance?
- Are there any requirements in NFPA 72, NFPA 2001, UL 864, or common manufacturer designs that address this scenario?
I'd appreciate explanations from anyone with experience in releasing panels or gas suppression systems.
Codes and standards do not eliminate every possible risk. Their goal is to reduce risk to an acceptable level.
While critical hazards are addressed through design and testing, some risks are managed through periodic inspection, preventive maintenance, functional testing, and replacement of components throughout the system's service life.
Codes and standards do not eliminate every possible risk. Their goal is to reduce risk to an acceptable level.
While critical hazards are addressed through design and testing, some risks are managed through periodic inspection, preventive maintenance, functional testing, and replacement of components throughout the system's service life.
I tested a TRIAC controlled by a microcontroller without an optocoupler. It worked, but I noticed something surprising.
With the load connected through MT2 and MT1 referenced to neutral, everything worked.
When I reversed the load connection in series with mt1, the circuit failed and damaged components.
Theory says a TRIAC is a bidirectional device, unlike a normal diode, so why does MT1/MT2 load orientation matter in practice?
Is this related to gate triggering reference, parasitic paths, or dv/dt effects? I would like to understand the real-world behavior behind this.
Situation:
During troubleshooting of a conventional fire alarm panel, a ground fault indication appeared. I initially suspected common causes such as battery leakage, insulation failure, or an actual field wiring ground fault, but all field checks were normal.
During testing, I noticed the batteries were weak. To verify, I connected only one fresh 12 V battery to the panel, and surprisingly the ground fault indication appeared again.
This led to an interesting observation: Can a reduced or unstable battery voltage cause a fire alarm panel to report a ground fault even when no actual field ground fault exists?
Has anyone experienced a similar situation, and what is the technical reason behind this behavior? Could it be related to the panel's ground fault detection reference circuit, voltage thresholds, or supervision circuitry?
I am trying to make a low voltage DC circuit breaker using a microcontroller and want to understand the basic working principle for educational purposes.
I understand that a traditional breaker uses thermal or magnetic mechanisms to trip, but how does a microcontroller-based DC breaker detect faults and disconnect the load?
Does the microcontroller directly control the high-current path, or does it use components like MOSFETs, IGBTs, relays, or contactors?
What are the main building blocks I should learn about to design one safely?
Edit: low current detection like human touch.
Both AC mains and batteries have a voltage difference, so why does touching a single AC wire shock you while touching only the positive or negative terminal of a battery does not?
What is the actual path that allows current to flow through the human body in each case?