Search found 110 matches

by Archibald
Sun May 16, 2021 10:04 am
Forum: ESP32 Arduino
Topic: Wakeup mode
Replies: 2
Views: 4488

Re: Wakeup mode

Consider inverting electronically. The CD4049 CMOS integrated circuit has maximum quiescent current of 1μA, typically 0.02μA.
by Archibald
Mon Mar 22, 2021 10:24 am
Forum: General Discussion
Topic: ESP32 audio output
Replies: 10
Views: 46644

Re: ESP32 audio output

how to add volume ?
Do you wish to make the audio louder or do you wish to have control of the volume?

If you wish to control the volume, do you wish to control it with a knob or digitally such as by using 'up' and 'down' buttons?

Are you using DAC or I²S?
by Archibald
Thu Feb 11, 2021 10:20 pm
Forum: Hardware
Topic: Power supply schematic
Replies: 6
Views: 6348

Re: Power supply schematic

It may be better to use a 5V plug-in power supply instead of the item from Farnell and to use a 3.3V voltage regulator such as this example. Then you will simply need 2 capacitors and a barrel socket. This would avoid hazardous mains voltage.
by Archibald
Mon Dec 16, 2019 1:17 pm
Forum: General Discussion
Topic: ADC speed?
Replies: 29
Views: 81621

Re: ADC speed?

I tried running the example program of peripherals/adc and found that each conversion took about 40us. That mean, a sampling speed of 25K Samples/second. Is that really possible or I am being mistaken? As reported in an earlier post in this thread, I have measured 9.5μs (including the time taken to...
by Archibald
Mon Oct 08, 2018 11:05 pm
Forum: General Discussion
Topic: Bad readings from ADC
Replies: 10
Views: 20201

Re: Bad readings from ADC

Could be induced voltage on the connection between pot and pin. Put a 100nF cap as close as possible to pin and ground and use exponential filtering in software. Thanks, but as I get readings from a potentiometer on an Arduino Micro that only vary between adjacent values, I don't think induced volt...
by Archibald
Sat Oct 06, 2018 4:48 pm
Forum: General Discussion
Topic: Bad readings from ADC
Replies: 10
Views: 20201

Re: Bad readings from ADC

For realy serious ADC performance analyzes you should use some precision voltage reference source, not the potentiometer which can introduce errors by itself. Thanks for your comment. Voltmeter readings indicate that the ADC input voltage is stable to within 1mV over several hours. With no delay in...
by Archibald
Sat Oct 06, 2018 9:53 am
Forum: General Discussion
Topic: Bad readings from ADC
Replies: 10
Views: 20201

Re: Bad readings from ADC

The bottom line is that I don't know what to expect for noise with a measurement like you are doing. For a good ADC with constant input voltage we should expect successive digital readings to either remain constant or to waver between two adjacent digital values. The digital readings can reasonably...
by Archibald
Fri Oct 05, 2018 6:14 pm
Forum: General Discussion
Topic: Bad readings from ADC
Replies: 10
Views: 20201

Re: Bad readings from ADC

How are you powering the pot? Are you using a separate regulated supply? I also see a lot of noise on the ADC. So what you are seeing (<3%) isn't that bad compared to what I'm seeing. Although I'm reading a sensor with a lot of amplification. I'm powering the development board and pot by a 5V switc...
by Archibald
Fri Oct 05, 2018 4:47 pm
Forum: General Discussion
Topic: Bad readings from ADC
Replies: 10
Views: 20201

Re: Bad readings from ADC

fly135 wrote:Try putting a delay between readings.
Thanks for the suggestion. With 10ms in the loop, I still get a similar spread of rogue readings.
by Archibald
Fri Oct 05, 2018 10:53 am
Forum: General Discussion
Topic: Dev Kit C without the external pins
Replies: 2
Views: 4989

Re: Dev Kit C without the external pins

I have removed similar header pins from an Arduino one at a time using a soldering iron. The plastic melts sufficiently. I was holding the Arduino in a small vice along its sides and pulling each pin out with pliers.

Alternatively, shorten the pins using side (diagonal) cutters.