Relay open drain output (allow esp32 to drive 5v relay modules) #3920
Conversation
|
I have exactly the same (visually) relays in daily use and never experienced any issues with normal OUTPUT setting. |
|
@blazoncek do you power it from 5V or 3.3V? Both problems are fixed when powered with 5V and controlled by a 5V logic level. |
|
5V. |
blazoncek
left a comment
blazoncek
left a comment
There was a problem hiding this comment.
I've checked my old notes and there was a problem with one particular relay (which I attached to pre-release prototype of Dig-Uno) that didn't work. Since then Dig-Unos include level shifter for relays as should any hardware that mixes 3.3V logic with 5V logic.
That does not mean anything though. 😄
Question: does it make sense to combine both inverted/non-inverted with open_drain? If not, then it might be better to have a drop-down with 3 options: normal/inverted/open_drain, instead of two independent checkboxes? |
|
@Suxsem Very good ,I have a lot of those exact relays and they would only work if powered from 3.3V ( which as you |
That is a very good observation! |
@softhack007 @blazoncek I think they should be kept separate: all 4 combinations of inverted / open drain are valid. 3.3V relay modules should not use open drain but some may have an active-low logic and others may have active-high logic. 5V relays should use the open drain option with the pull up resistor but some of them uses an NPN transistor and others a PNP one so open-drain and inverted could be useful |
wled00/data/settings_leds.htm
Outdated
| <div id="json" style="display:none;">JSON file: <input type="file" name="data" accept=".json"><button type="button" class="sml" onclick="uploadFile('/ir.json')">Upload</button><br></div> | ||
| <a href="https://kno.wled.ge/interfaces/infrared/" target="_blank">IR info</a><br> | ||
| Relay GPIO: <input type="number" min="-1" max="48" name="RL" onchange="UI()" class="xs"> Invert <input type="checkbox" name="RM"><span style="cursor: pointer;" onclick="off('RL')"> ✕</span><br> | ||
| Relay GPIO: <input type="number" min="-1" max="48" name="RL" onchange="UI()" class="xs"> Invert <input type="checkbox" name="RM"> Open drain <input type="checkbox" name="RO"><span style="cursor: pointer;" onclick="off('RL')"> ✕</span><br> |
There was a problem hiding this comment.
Can you move the X (span) next to input field and then I'll merge.
|
Something might be you could also fix if possible is the multi-relay usermod |
4 participants
This PR adds a new boolean option to the relay settings: open drain.
When select, relay pin mode is set to OUTPUT_OPEN_DRAIN instead of normal OUTPUT.
This allow driving 5v relay modules (cheap super common Arduino ones) just powering them with 5V and adding an external pull-up resistor between the module input pin and 5V, without risking the esp32 pins (that are not 5v-tolerant) and without additional level converters.
Fully tested