23
votes
Accepted
ESP8266 eLUA (NodeMCU) vs MicroPython
Here's a slightly different approach in stead of a Lua vs. Python shootout:
Six of the most popular ESP8266 "runtimes":
AT Command SET. Popular when the 8266 is paired with another MCU.
Communicates ...
- 1,845
20
votes
Accepted
Is this a sensbile way to switch a 12V line with 3.3V logic
Lots of problems with your circuit:
T1 is used as a emitter follower. Its output will therefore be less than the 3.3 V input. Figure 700 mV for the B-E drop, and the maximum the gate of Q1 is ...
- 315k
15
votes
Accepted
ESP8266 - is it used in real industry?
The ESP8266 chip is relatively new to the market (circa 2014, I think). So it's short market availability has limited its adoption somewhat -- some early adopters have chosen it, but that's usually ...
- 709
15
votes
Accepted
How to drive 700mA LED cheaply?
XY problem.
Your best efficiency solution from a power and cost point of view to drive a 1A LED load is to use a LED driver IC. There are many to choose from; the Diodes Inc PAM2804 seems likely to ...
- 58.1k
14
votes
Accepted
ESP32: how to keep a pin high during deep sleep (RTC GPIO pull-ups are too weak)?
Well, sorry to revert my acceptance to the answer by Harry Svensson! And I shouldn't really be adding to a question that is 14 months old by now.
However I just found the perfect software solution, ...
- 5,497
14
votes
Accepted
Is it better to use a MOSFET with a gate driver IC or a MOSFET with a lower VGS,on?
which is best for fast switching do I need to use MOSFET driver IC such as ICL766 with IRFZ44n or is it better to use lower VGS MOSFET such as AO3400
You don't want fast switching to drive LED strips!...
- 81.6k
12
votes
Accepted
Do I really need diodes to receive MIDI?
The diode is there to protect the opto-LED in the event of a reverse polarity connection.
The HF11L datasheet states that the absolute maximum reverse voltage for the emitter (meaning the IR emitter,...
- 180k
11
votes
Accepted
How is the esp8266 is able to generate 2.4 GHz wifi signals?
The radio contains a voltage controlled oscillator that is locked to an external reference oscillator using a phase locked loop (PLL). This results in a very precise high frequency signal for the ...
- 41.6k
11
votes
Low pass filter with two capacitors?
It's simply an AF (audio frequency) coupling capacitor, removing any DC that is on the signal.
- 39.2k
10
votes
Accepted
Low pass filter with two capacitors?
The first RC does indeed act as a low pass filter.
The second capacitor (the one on the right), combined with the load impedance presented by whatever is connected to the audio out, acts as a high ...
- 5,611
10
votes
How to drive 700mA LED cheaply?
I read about a method of limiting current using 2 transistors (schematic attached below).
All linear solutions, resistor or whatever, will have the same efficiency.
If you run the LED at 1A, it will ...
- 81.6k
10
votes
Controlling Relay using ESP8266 Module
Here's what your schematic is (left) and what I would use (right):
simulate this circuit – Schematic created using CircuitLab
The left schematic will act like a (sort of) current source, where ...
- 81.4k
9
votes
Accepted
Replace AMS1117 5V-3.3V LDO on NodeMCU for LiPo with low quiescent current
You choice looks good to me, but only if your NodeMCU is going to spend most of its time sleeping. In that case I'd use a MCP1700 (quiescent current < 4 uA).
If it's going to spend a significant % ...
- 5,841
9
votes
433 MHz VS. Manhole Cover
There will be gaps around the manhole cover, either air due to sloppy fit, or in the concrete/bricks. The 2.4GHz exploits those gaps with its 100cm/(11 * 4) = 100cm/44 = 2.2cm quarter-wavelength to ...
- 35k
9
votes
Is ESP8266 an AVR?
ESP family isn't a AVR!
The Library you refere to is a Arduino IDE (Integrated Development Environment) library.
The Arduino IDE has a hardware layer that gives it the ability to utilize several ...
- 778
9
votes
Trying to get (more) accurate readings from thermistor (electronics, math, and code inside)
The ESP8266 ADC is not really a very good one for instrumentation purposes. I believe it's not very linear (especially for voltages near 0V) and the internal reference voltage might be +/-10% or worse ...
8
votes
Accepted
Using MOSFET to turn on/off a sensor controlled by ESP8266
Using a P channel MOSFET to switch the power is reasonable, but the way you propose to drive the gate is not.
The microcontroller can drive the gate basically to ground, so turning the FET on is no ...
- 315k
8
votes
How to connect GPIO16 and RST of ESP8266?
The answer from A. Roy solved a similar problem for me. I'm prototyping a a circuit using a Nodemcu devkit board https://github.com/nodemcu/nodemcu-devkit-v1.0 with an ESP-12E. The board has an ...
- 81
8
votes
Accepted
ESP32 logic HIGH/LOW level voltage, not working?
The spec says that the input is guaranteed to be read as a Low below 0.25 Vdd, and as a High above 0.75 Vdd.
It does not specify where the actual switching threshold is - from the spec, we only ...
- 60.7k
8
votes
Accepted
FT232 stops being recognized after wiring ESP-01S on Ubuntu
The FT232RL chip data sheet says you can pull only up to 50mA from the internal 3.3V regulator for external purposes.
The ESP01-S module can take more than 50mA even when receiving a wireless packet.
...
- 172k
7
votes
Accepted
3,8 Volt to 1 Volt via Voltage Divider
The device you have does not provide an analog output- it is a simple resistance comparator (bridge circuit into an LM393 inputs):
Since the LM393 has an open-collector output, your loading it will ...
7
votes
Is there a way to trigger a 5V relay that is more robust than just feeding it with 5 V?
For critical systems, a failsafe circuit is used that has to be toggled continuously to activate the relay.
The GPIO pin is toggled in the main software loop (typically) after doing all the normal ...
- 3,751
7
votes
Is this a sensbile way to switch a 12V line with 3.3V logic
No this is probably not a sensible approach because the N channel MOSFET is wired as a source follower and cannot therefore produce a voltage output that is any greater than the gate drive voltage. In ...
- 473k
7
votes
Trying to get (more) accurate readings from thermistor (electronics, math, and code inside)
Unless you have a better than 1C temperature reference, I would not bother trying to get a higher absolute accuracy than what you get using nominal data sheet info. If you need a true high accuracy ...
- 3,586
7
votes
Accepted
Linear regulator doesn't keep the right voltage when connected to ESP8266
The datasheet states a the minimum Vin must meet 2 conditions, one of them being:
\$V_{in} >(V_r + 3\%) + V_{DROPOUT} \$
which for a 3.3V regulator becomes
\$V_{in} >(3.3V + 3\%) + V_{...
- 10.9k
7
votes
3.7v to 3.3v voltage regulator
A battery's voltage sags as it discharges and the LiPo type is no exception. A 3.7V LiPo battery falls to about 3.0V when fully discharged. You will want your project to continue operating over the ...
- 695
7
votes
ESP8266/ESP-12F gets damaged when powered by LDO (LD1117v33) every time
You NEED the capacitors, in particular the (recommended 10uF minimum) OUTPUT capacitor. A 10uF electrolytic- aluminum or tantalum (or a 22uF ceramic with a couple ohms in series) will do. The input ...
7
votes
How to measure voltage of a system with a different GND reference?
Measure the voltage of '?', and the voltage of GNDD, simultaneously, then subtract.
A way to do this with one channel rather than two is to measure the difference between ? and GNDD with a ...
- 174k
7
votes
Accepted
MOSFET driver: Totem Pole or NPN Self-Biasing Turn-Off Circuit
A couple of minutes on Mouser yielded these through-hole drivers which should work in your application:
UC3705 from Texas Instruments
MIC4426 from Microchip
In the spirit of the question, I think ...
- 47k
6
votes
Microcontroller hangs while switching off
When you hold the button down and the micro drives the ON/OFF line low, there's a low-impedance path directly from the battery, through the I/O protection diodes on ...
- 178k
Only top scored, non community-wiki answers of a minimum length are eligible