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by boyoh
Mon Feb 24, 2020 6:52 pm
Forum: Beginners
Topic: Non Contact Voltage Detector Mashup
Replies: 9
Views: 246

Re: Non Contact Voltage Detector Mashup

BoyOh, The mains are connected to two inverters so I do not have an outlet or circuit that is not always energized. I do not have a good place to put the relay. This has me looking at using a SCT013-000 but have not figured a circuit for that either. I am still learning electronics so am being care...
by boyoh
Mon Feb 24, 2020 11:37 am
Forum: Beginners
Topic: Non Contact Voltage Detector Mashup
Replies: 9
Views: 246

Re: Non Contact Voltage Detector Mashup

Might I suggest using a small mains relay connected to the mains power supply protected by a fuse This will be on 24/7 . Then using a pair of normally closed contacts to switch the 3.3v to the Pi in/put. When the power fails the relay will de-energize , the N / C contacts will make to switch the 3.3...
by boyoh
Wed Feb 19, 2020 11:31 pm
Forum: Beginners
Topic: Where could I find the online tutorials to match this kit?
Replies: 6
Views: 244

Re: Where could I find the online tutorials to match this kit?

Books on simple electronics to use for learning Try books by " Forrest M. Mims " There are a series of them

Basic Semiconductor Circuits. There are many to pick from ( Enter Books by Forest M. Mims )



Regards BoyOh
by boyoh
Tue Feb 18, 2020 11:42 pm
Forum: Beginners
Topic: Consumption raspberry pi zero w
Replies: 9
Views: 213

Re: Consumption raspberry pi zero w

Formulate your readings. You can use this chart to work it all out, . THE-PIE-CHART-FOR-OHM’S-LAW[1].png How many errors are in that chart? From BoyOh IF THERE ARE ERRORS IN the chart " POINT THEM OUT" I did not designee the chart, I think the designee would like to Know Regards BoyOh
by boyoh
Tue Feb 18, 2020 5:17 pm
Forum: Beginners
Topic: Consumption raspberry pi zero w
Replies: 9
Views: 213

Re: Consumption raspberry pi zero w

hello, I wanted to know the consumption of my system but I do not know how to calculate. I have a raspberry pi zero w, Raspberry Pi GSM/GPRS/GNSS , a V2 camera module and an accelerometer I Would do two tests On Load & Off Load Using a multi meter....Voltage test will be Parallel to the supply Curr...
by boyoh
Tue Feb 18, 2020 3:23 pm
Forum: Beginners
Topic: The energy consumed by a raspberry card
Replies: 18
Views: 571

Re: The energy consumed by a raspberry card

ohms-law.gif BoyOhTHE-PIE-CHART-FOR-OHM’S-LAW[1].png What Paeryn said. Plus, that graphic appears to have two incorrect formulae -- the ones involving square roots. Should be: P=√(PR) I=√(P/R) At least I think so. It's late :!: BoyOh You said the last chart was wrong, I hope this one is correct ,an...
by boyoh
Tue Feb 18, 2020 12:28 pm
Forum: Beginners
Topic: The energy consumed by a raspberry card
Replies: 18
Views: 571

Re: The energy consumed by a raspberry card

Ohm's Law concerns voltage, current and resistance. It is irrelevant if one has values for voltage and current and wishes to calculate power ("wattage"). from BoyOh The watt (symbol: W) is a unit of power. In the International System of Units (SI) it is defined as a derived unit of 1 joule per seco...
by boyoh
Mon Feb 17, 2020 11:00 pm
Forum: Beginners
Topic: The energy consumed by a raspberry card
Replies: 18
Views: 571

Re: The energy consumed by a raspberry card

from BoyOh The watt (symbol: W) is a unit of power. In the International System of Units (SI) it is defined as a derived unit of 1 joule per second, and is used to quantify the rate of energy transfer If you read the posters question you will see the Word ENERGY Regards BoyOh But as drgeoff said, O...
by boyoh
Mon Feb 17, 2020 8:40 pm
Forum: Beginners
Topic: The energy consumed by a raspberry card
Replies: 18
Views: 571

Re: The energy consumed by a raspberry card

Ohm's Law concerns voltage, current and resistance. It is irrelevant if one has values for voltage and current and wishes to calculate power ("wattage"). from BoyOh The watt (symbol: W) is a unit of power. In the International System of Units (SI) it is defined as a derived unit of 1 joule per seco...
by boyoh
Mon Feb 17, 2020 5:34 pm
Forum: Beginners
Topic: The energy consumed by a raspberry card
Replies: 18
Views: 571

Re: The energy consumed by a raspberry card

Sorry, Boyoh, but you are misremembering what is Ohm's Law and what is Watt's Law. Ohm's Law concerns the relationship of voltage (V, in Volts), current (I, in Amps) and Resistance (R, in Ohms). V=IR Watt's Law concerns the relationship of power (P, in Watts), voltage (V, in Volts) and current (I, ...
by boyoh
Sun Feb 16, 2020 5:12 pm
Forum: Beginners
Topic: The energy consumed by a raspberry card
Replies: 18
Views: 571

Re: The energy consumed by a raspberry card

Ohm's Law concerns voltage, current and resistance. It is irrelevant if one has values for voltage and current and wishes to calculate power ("wattage"). from BoyOh The watt (symbol: W) is a unit of power. In the International System of Units (SI) it is defined as a derived unit of 1 joule per seco...
by boyoh
Sun Feb 16, 2020 11:13 am
Forum: Beginners
Topic: The energy consumed by a raspberry card
Replies: 18
Views: 571

Re: The energy consumed by a raspberry card

First is to check the voltage and the current , then using Ohms Law to give you the Wattage. Ohm's Law concerns voltage, current and resistance. It is irrelevant if one has values for voltage and current and wishes to calculate power ("wattage"). from BoyOh The watt (symbol: W) is a unit of power. ...
by boyoh
Sat Feb 15, 2020 11:37 pm
Forum: Beginners
Topic: The energy consumed by a raspberry card
Replies: 18
Views: 571

Re: The energy consumed by a raspberry card

First is to check the voltage and the current , then using Ohms Law to give you the Wattage. You do the tests on / load and off/ load . For testing on load use a high wattage high specs resistor . Make Shure the resistor you use will not take the current beyond the Pi full load Then the rest is up t...
by boyoh
Sat Feb 15, 2020 7:12 pm
Forum: Beginners
Topic: Switching from Arduino to RPi, what parts to buy
Replies: 5
Views: 224

Re: Switching from Arduino to RPi, what parts to buy

You are given the option of setting the GPIO I/P To a impedance level that the processor can respond to. In its high impedance state floating, It will not, sink or source a working level signal. This being a logic level 0 low or 1 high, So you must set it to a working impedance level by setting the ...
by boyoh
Thu Feb 13, 2020 11:36 pm
Forum: Beginners
Topic: Wiring inductive sensors in series
Replies: 38
Views: 734

Re: Wiring inductive sensors in series

You can't put optos in series. Not very many anyway as I explained in my first post. Or any optos at all in this case. Good points Peter. IIRC there was an upper limit to the resistance though. A huge improvement over that first diagram TecHnoGuy. We are definitely headed in the right direction. I ...
by boyoh
Thu Feb 13, 2020 11:35 pm
Forum: Beginners
Topic: Wiring inductive sensors in series
Replies: 38
Views: 734

Re: Wiring inductive sensors in series

You can't put optos in series. Not very many anyway as I explained in my first post. Or any optos at all in this case. Good points Peter. IIRC there was an upper limit to the resistance though. A huge improvement over that first diagram TecHnoGuy. We are definitely headed in the right direction. I ...
by boyoh
Thu Feb 13, 2020 4:34 pm
Forum: Beginners
Topic: Wiring inductive sensors in series
Replies: 38
Views: 734

Re: Wiring inductive sensors in series

My advice is stick to your first circuit and use the opto Isolaters transistors in Series Using 5v instead of 3.3v through the opto transistor chain.. Use a Opto Isolator from the last opto isolator in the chain as a voltage leveler 3.3v to the GPIO IN / PUT. No need for Potential Dividers This mean...
by boyoh
Tue Feb 11, 2020 11:24 pm
Forum: Beginners
Topic: Wiring inductive sensors in series
Replies: 38
Views: 734

Re: Wiring inductive sensors in series

Thanks for the reply. I hadn't heard of opto-isolators before so never would have thought of it. Just to check that I have understood correctly I have made a circuit diagram where the symbols labelled IC are the opto-isolators. Pi_Senssor-Circuit_1.png (Edit: And also I assumed resistors would be n...
by boyoh
Tue Feb 11, 2020 9:09 pm
Forum: Beginners
Topic: Wiring inductive sensors in series
Replies: 38
Views: 734

Re: Wiring inductive sensors in series

Thanks for the reply. I hadn't heard of opto-isolators before so never would have thought of it. Just to check that I have understood correctly I have made a circuit diagram where the symbols labelled IC are the opto-isolators. Pi_Senssor-Circuit_1.png (Edit: And also I assumed resistors would be n...
by boyoh
Tue Feb 11, 2020 8:17 pm
Forum: Beginners
Topic: interfacing multiple components with Raspberry pi
Replies: 3
Views: 95

Re: interfacing multiple components with Raspberry pi

how to interface an ultrasonic sensor, moisture sensor and gsm module with Raspberry-pi 3 B+ and how to write the program? From BoyOh Do you understand basic Electronics ? Do you understand how the Raspberry Pi In /Put & Out/Put's work The Raspberry Pi is NOT PLUG & PLAY You have some research to d...
by boyoh
Fri Feb 07, 2020 11:55 am
Forum: Beginners
Topic: Fitting a fan without using GPIO?
Replies: 20
Views: 425

Re: Fitting a fan without using GPIO?

Pi Board.jpg
Pi Board.jpg (60.13 KiB) Viewed 101 times

You could use this board for building your projects on , I fitted 4 slotted Opto Isolators for voltage leveling
and projects control .All built on Vero Board .Good project for learner

Regards BoyOh
by boyoh
Thu Feb 06, 2020 9:32 pm
Forum: Beginners
Topic: Fitting a fan without using GPIO?
Replies: 20
Views: 425

Re: Fitting a fan without using GPIO?

You could fit the Fan in the Pi box , and having it temperature controlled just using the 3.3v rail and 5volt for the fan , Using a NTC Thermistor switching a transistor to switch the fan on and off , The thermistor is Temperature controlled resistor If you do use a Thermistor use a preset in series...
by boyoh
Tue Feb 04, 2020 3:57 pm
Forum: Beginners
Topic: Powering a RPi 3B+ through GPIO vs USB
Replies: 14
Views: 390

Re: Powering a RPi 3B+ through GPIO vs USB

The Pi is not designed to be used as a power house. If you want to run power hungry projects ,you must use buffer stages , and let the Pi control them with low power signals The USB connection is the one to use . Using GPIO to feed the power to the Pi is asking for problems ,and also bypassing the s...
by boyoh
Sun Feb 02, 2020 10:23 am
Forum: Beginners
Topic: Using different sensors wiring
Replies: 11
Views: 887

Re: Using different sensors wiring

These are examples of how to use both a potential divider circuit and an opto isolator to connect the sensor to your pi. I would consider the opto isolator circuit the better option especially if you are going to be using a sensor voltage nearer the 36V maximum. https://i.imgur.com/Ww07eGK.jpg You ...
by boyoh
Sat Feb 01, 2020 8:42 pm
Forum: Beginners
Topic: Raspberry Pi control Relay with momentary switch
Replies: 27
Views: 1814

Re: Raspberry Pi control Relay with momentary switch

You've got more patience than me, drawing diagrams that way! As long as the resistors are high enough (10K) the diodes should be unnecessary. There are still two minor issues for the OP to iron out: 1. If the Pi fails with the GPIO high, the lights will be held on. 2. If the Pi fails with no 3V3 su...

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