Hello. I am using this setup, as shown in the second image here (Compatible LED strips - WLED Project). The only two differences being:
- I am using an ESP8266 and therefore different GPIO ports.
- I am powering the ESP using the ground and 5V pins, using the same 24V Power supply that is powering my strip. With a step-down buck converter in between.
Now when plugged in, the LED strip lights up at with a bright white light (always at full intensity), regardless of what color I setup in the WLED web interface.
The ESP is running, the WLED interface is working as expected, changing color or brightness just doesnât do anything.
On the input ports of the LED-Amp, there is a voltage of 0V to a maximum of 3.3V on each channel. When I set blue for example the first channel has an input voltage of 3.3V, channel 2 and 3 a voltage of 0V. Therefore, I assume that the ESP is working correctly.
However, the output voltage is always at 24V on every channel, regardless of the input voltage.
@Jinx the WEMOS D1 Uno R2 shield at 4USD go from 9-24V input on the Boardpower
I use them all on Car Battery 14.4V Stable working on timer for 1Month Timed on and off for the X-mas display show .
THE D1 MINI Board Alone do only cope with 5.2V on the 5V Pin
Hello, thank you for your reply. I tried bridging the ESPs GND to the PSUs GND (I hope that is what you were suggesting).
I added an image below, the red wire is the one I added. However, that did not change anything. Feel welcome to correct my sketch if I wired up anything incorrectly, or misunderstood your advice.
a few things to consider, your buck-converter most likely already bridges the two grounds, no extra wire needed there. your RGB-amp maybe using a 5v control signal. do you have a serial or part-number? maybe we can deduce some more info from that.
If I go off the info in the other forum post link you gave you have to adjust to the following:
link the rgb-amp + to the 3.3V (detach from PSU) ( this is so the V+ on the esp side can be compared to the + signal)
detach the rgb-amp V+ from the strip.
link the strip directly to the psu 24V
This only works if the RGB-amp is designed to handle the low voltage. otherwise you need a step up between the esp and the controller box.
The OP did not say anything about that âunoâ board, nor did you when you told them to send 12v to their Esp8266.
-Please try to be clear because if the OP is using a regular Esp8266 and if someone tells them to send 12v to a 5v pin they are VERY likely to end up with broken hardware and or a fire. Not trying to bash you. Just trying to keep everyone from having a possible bad outcome.
@Elius For the heck of it, try powering the Esp from the USB port and see if it works like the pic shows. If it works, then maybe you do need the ground isolation on the controller side.
In the non-addressable led section it shows a picture with the mosfets then it shows the picture using the led amplifier, which from what I can see is just the mosfet diagram solution with some extra protection in the form of the octocoupler?
But but it mentions a required version in between the two solutions/offerings.
The basic issue with non-addressable vs addressable LEDs is that the data line on addressable LEDs needs no appreciable current and just talks to the âsmartâ LED and tells it what to display for colour. The smart LED takes what ever current it needs from the power supply connections.
In contrast, analog LEDs require the âdata driving outputâ (a GPIO pin on the ESPâs) to supply them with the actual current they need to light up. With more than 1 LED the ESP just canât handle that kind of current load.
The MOSFETs will allow the LEDs to draw what current they need while at the same time switching on and off very rapidly as required by the WLED softwareâŚ
The âAmplifierâ devices shown are just MOSFETs that are connected to the ESP board via optocouplers vs a direct connection. The direct connection will also work well as long as you choose the proper MOSFETs - they need to tuirn on fully with only a 3.3V input from the ESP.
The WLED version requirement applies to all the non-addressable approaches. You want to be on V 0.13-1 (thatâs quite old now) or more recent.
Wow thank you for taking the time to reply so thoroughly.
It was the clarification around the version of wled and the 2 solutions. I suspected it wasnât material to the solution.
The challenge I have is my LEDs are 5v and the led amplifiers all seem to assume you want to work with 12.
Some of the boards on Amazon for example claim to be 4 channel mosfet (with optocoupler) and with a trigger of 3.3v but in the reviews people are saying it doesnât work with esp and actually the trigger is more like 5v and hence doesnât work.
Currently eyeballing this⌠which seems to be the ticket ln the TRIGGER side but seems to prefer 9v or higher - I donât see how it cares really what goes through the gate once triggered so likely fineâŚ
The general issue with MOSFETs is their Vgs - the minimum voltage needed to trigger the Gate of the device to turn fully on. When on full, the MOSFET has very small resistance from Drain to Source, it acts like a pretty good switch. Unfortunately, thereâs a region of operation just before it switches on full where it acts more like a resistor and will draw lots of power, drastically reduce the brightness of your LEDs and heat itself up.
The trick is to find a device that operates well with a lower Vgs. Many of the Ali devices you see will use a higher âSupply Voltageâ to create a higher voltage Gate drive circuit from a low voltage input (sometimes using optocouplers).
One other thing you can do is add one of the levelshifters designed for addressable LEDs to the PWM analog GPIOs. That will boost your Gate drive to 5V, which can make your MOSFET search a little easier.
Some food for thought. I have purchased the ali item as it will take time to arrive and consider the level shifter.
Something that occurred to me, one imagines this led strips varies the intensity of the red, green and the blue and therefore sets the colour by drawing a range of juice for each of them.
Not really sure how that might work, as according to the track it is 5v and RGB so 4 pins total suggesting the colour pins are the âgroundâ essentially and the 5v is the fixed amount.
Assuming there is more nuance nuance than that, is there danger that would get lost in translation with a mosfet or even a level shifter (although that feels like it can be more nuanced)
Youâre bang on about RGB analog LEDs. The strip ties all the LED Anodes (V+) to the 5V line and you control the amount of current for each of the R, G, and B channels by connecting them to ground as needed.
The MOSFET acts as a switch that does the connecting to ground. The brightness you get comes from the amount of âOnâ time vs âOffâ time (the duty cycle) when you switch it rapidly. 25% On with 75% Off gives you (approx) 25% brightness.
All the choosing and specs for MOSFETs are done based on the âworst caseâ requirements of the entire strip at 100% bright White. That way youâll be covered for the full range of scenarios youâll see with the strip and you donât need to worry about the nuances getting lost in the shuffle.
