Search found 107 matches

by Archibald
Sat Mar 10, 2018 1:13 am
Forum: General Discussion
Topic: What is the best most safe way to drive this Relay?
Replies: 18
Views: 8232

Re: What is the best most safe way to drive this Relay?

If you completely disconnect the relay board, do you still get that same 1.4V to 1.8V on the ESP32 development board output pin? If so, that proves the issue is nothing to do with the relay board. You seem to have data on that pin during setup and during I²S audio. Have you considered controlling th...
by Archibald
Fri Mar 09, 2018 6:48 pm
Forum: General Discussion
Topic: What is the best most safe way to drive this Relay?
Replies: 18
Views: 8232

Re: What is the best most safe way to drive this Relay?

I understand the visible LED is in series with the LED within the optocoupler and a 470Ω resistor. The three items are connected between the +5V supply of the relay board and the input connection to the relay board. So if the visible LED is dimming, either the 5V supply is reducing or the input from...
by Archibald
Fri Mar 09, 2018 2:59 am
Forum: General Discussion
Topic: What is the best most safe way to drive this Relay?
Replies: 18
Views: 8232

Re: What is the best most safe way to drive this Relay?

I have been under the impression from forum posts that the maximum GPIO output current from an ESP32 is 12mA whereas your relay board requires 15 to 20mA. That's partly why I have been suggesting the need to have a buffer capable of supplying up to 20mA. However, I have just checked the datasheet of...
by Archibald
Thu Mar 08, 2018 6:13 pm
Forum: General Discussion
Topic: What is the best most safe way to drive this Relay?
Replies: 18
Views: 8232

Re: What is the best most safe way to drive this Relay?

Yes, the octal buffer needs a 5V supply. I would expect you to use the same supply that you use for your relay board. I would be very apprehensive about using USB power. If you are using an ESP32 development board that requires a 5V supply, I would recommend using the same supply. When using separat...
by Archibald
Wed Mar 07, 2018 8:47 pm
Forum: General Discussion
Topic: What is the best most safe way to drive this Relay?
Replies: 18
Views: 8232

Re: What is the best most safe way to drive this Relay?

According to information from Amazon and directly from Elegoo, each channel requires 15 to 20mA drive current. It is not clear whether that is for input low or high, but probably low. The data you link to regarding the relay is irrelevant because there is evidently an 817C optocoupler for each input...
by Archibald
Mon Mar 05, 2018 7:53 am
Forum: General Discussion
Topic: ESP32 audio output
Replies: 6
Views: 18451

Re: ESP32 audio output

all I get is noise on the speaker that is connected to the Adafruit amp. For I²S your data needs to be signed in two's complement form. If not you will get extreme distortion that sounds rather like noise. (If you use one of the ESP32's digital-to-analogue converters, the data needs to be unsigned.)
by Archibald
Mon Mar 05, 2018 2:27 am
Forum: General Discussion
Topic: ESP32 audio output
Replies: 6
Views: 18451

Re: ESP32 audio output

Using I²S should give you really good sound quality so it's probably well worth trying to get it to work. If you find you can't make progress, I suggest you use one of the digital-to-analogue converter (DAC) outputs of the ESP32. For speech messages, I am using 8-bit samples at 8kHz stored in ESP32 ...

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