Use a triggered timer like -
https://www.aliexpress.us/w/wholesale-triggered-timer.html?spm=a2g0o.home.search.0
Check that timer will activate a load AFTER the time delay. Use a low voltage buzzer
for alarm sound.
Take a look over here at some videos of solutions done.
Regards, Dana.
It means cap still has its dielectric intact, at the LV that the meter uses.
Generally says cap may be OK,unless its actual capacitance has changed and circuit
no longer can function. Can your meter measure capacitance ?
Generally the scale with buzzer is a continuity indicator, low...
The grounds, the negative side of both V supplies, are isolated ? If so then use a SSR
or optocoupler. What is the current flowing in the 1.75 supply ?
If not isolated grounds then a N channel MOSFET, drain connected to - side 1.75, source to
ground, gate to switched side of 5V. Use a logic...
If you look at the Nodemcu schematic can you can see the pins that
need to be committed :
https://circuits4you.com/wp-content/uploads/2017/12/nodemcu-circuit-diagram.png
https://electropeak.com/learn/esp8266-pinout-reference-how-to-use-esp8266-gpio-pins/
Look at pin priority notes topics in...
Various circuit configurations to test opamp parameters :
https://www.analog.com/en/analog-dialogue/articles/simple-op-amp-measurements.html
Regards, Dana.
For future as you get more experience, the FFT approach in post #43 was minimal
components.
For filter approach same chip can do two filters/chip, using small number chip resources. Example
of 50 Hz and 60 Hz :
Filter just done with above wizard. Note I did not show 2'ond DAC, also onchip...
I went to A school there as well, used 260 but do not remember overload button.
We also used them on boat, SSN-583.
Still have one, use occasionally. Also have a VTVM version just picked up.
Quality materials, parts, great stuff.
Regards, Dana.
Assuming you have a driver you would :
driver >> LED strip >> NO contact on relay, GND of relay same ground as drivers
output. Is driver constant current or voltage ? Reason for asking what limits
LED current in the strip ?
But best if you post part number/link to driver and led strip...
D5 mounted on board with wrong direction ?
You met the input C ratings ?
Your layout does not seem to reflect the datasheet guidline layout ....?
Input C precautions, datasheet overall has a lot of precautions ....
Regards, Dana.
The SN74AHC1G14 should suffice, just the part no other passives needed other that a bypass cap
across its VCC and ground pins, say a 4.7 uF 10V tantalum :
https://www.ti.com/lit/ds/symlink/sn74ahc1g14.pdf
Note the transistor circuit, with 2 Rs and a cap, more parts but easier to build a...
Simple logic gate to invert would suffice. There are single gate logic families
that make life easy, cheap. low pin count.....
https://www.ti.com/pdfs/logic/littlelogicsg.pdf
If your Hall Sensor does not have noise rejection, eg. no hysteresis, then pick a gate with
Schmidt conditioned inputs...
With respect to filters or amplifiers :
1) We have Vin and Vout. Relationship between them is Vout = G x Vin.
or G = Vout / Vin (units are V / V). Eg. G is dimensionless. So if we have
Vout = 1V for Vin = .01V we have a G of 1 (V) / .01 (V) or 100 V/V or just
100.
2) db is G (decibels) = 20 x...