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by InsertTitle
Thu Nov 23, 2017 3:01 pm
Forum: Compute Module
Topic: Op Amp / Power op amp help with CM3 audio
Replies: 24
Views: 3095

Re: Op Amp / Power op amp help with CM3 audio

could I not simply wired in the 50K pot under AIN3 which is my currently free pin Thinking about it; you might not need a physical pot on the op-amp and/or power amp as you can probably use the ADC pot to adjust the volume, the signal level to that, in software as you would for the bluetooth audio....
by InsertTitle
Thu Nov 23, 2017 9:42 am
Forum: Compute Module
Topic: Op Amp / Power op amp help with CM3 audio
Replies: 24
Views: 3095

Re: Op Amp / Power op amp help with CM3 audio

I already have an ADC (ADC1115) that does my ultrasonic sensors could I not simply wired in the 50K pot under AIN3 which is my currently free pin and have it feed into the I2C of the CM3?

Or would I be better off having a separate ADC for just the bluetooth audio?
by InsertTitle
Wed Nov 22, 2017 4:26 pm
Forum: Compute Module
Topic: Op Amp / Power op amp help with CM3 audio
Replies: 24
Views: 3095

Re: Op Amp / Power op amp help with CM3 audio

Ah I see. Fair enough. Iconsider thread more or less answered now. Any ideas on my bluetooth query if not. Just means will have to do some googling about.
by InsertTitle
Wed Nov 22, 2017 3:20 pm
Forum: Compute Module
Topic: Op Amp / Power op amp help with CM3 audio
Replies: 24
Views: 3095

Re: Op Amp / Power op amp help with CM3 audio

In your original specification it seemed you wanted stereo for the headphones, mono for the speakers when the headphones were not plugged-in. Has that specification changed ? If that is the case, then you'll need two LM386's (or equivalents - TDA2822M?) and a 3.5mm jack with additional switch conta...
by InsertTitle
Wed Nov 22, 2017 2:50 pm
Forum: Compute Module
Topic: Op Amp / Power op amp help with CM3 audio
Replies: 24
Views: 3095

Re: Op Amp / Power op amp help with CM3 audio

In your original specification it seemed you wanted stereo for the headphones, mono for the speakers when the headphones were not plugged-in. Has that specification changed ? Originally I was thinking stereo would be great for the headphones but I soon realised after watching a video on Mono vs Ste...
by InsertTitle
Wed Nov 22, 2017 2:02 pm
Forum: Compute Module
Topic: Op Amp / Power op amp help with CM3 audio
Replies: 24
Views: 3095

Re: Op Amp / Power op amp help with CM3 audio

I realised the error the C8 & C4 when I submitted the post as I had copied them from another capacitor and forgot to change the values so I changed the values in eagle and re-posted the image with the edit change. Didn't actually notice the R17 until you mentioned about it will change that now. So n...
by InsertTitle
Wed Nov 22, 2017 1:25 pm
Forum: Compute Module
Topic: Op Amp / Power op amp help with CM3 audio
Replies: 24
Views: 3095

Re: Op Amp / Power op amp help with CM3 audio

Following your suggestion of LM386. I assume this is what you're meaning? Correct me if wrong. The application examples uses a 10k Pot for gain but I've got a 50k Pot in my prior design would this work better for the circuit? Or will have to add on additional 15K resistor just to attenuate the signa...
by InsertTitle
Wed Nov 22, 2017 12:58 pm
Forum: Compute Module
Topic: Op Amp / Power op amp help with CM3 audio
Replies: 24
Views: 3095

Re: Op Amp / Power op amp help with CM3 audio

You appear to be shorting AUDIO_RIGHT to ground. Even without the short VR2 would be acting more as a balance control than gain. Either that or I'm missing some subtlety of your circuit. The feedback setup of a non-inverting op-amp circuit would normally have the right hand end of R28 connected to ...
by InsertTitle
Wed Nov 22, 2017 11:35 am
Forum: Compute Module
Topic: Op Amp / Power op amp help with CM3 audio
Replies: 24
Views: 3095

Op Amp / Power op amp help with CM3 audio

Trying to get audio running on the CM3 using GPIO40(PWM0) & 45 (PWM1) and convert the stereo output into a Mono output. Then I want to amplify the audio signals using an differential amp op circuit whilst using a potentiometer (pot) to control the volume (gain) which will be pushed into a 3.5mm head...
by InsertTitle
Tue Nov 21, 2017 8:15 pm
Forum: Compute Module
Topic: WiFi chip for Compute Module 3
Replies: 22
Views: 21691

Re: WiFi chip for Compute Module 3

Here's some good news for you I ended up looking into this for my own project and I came across the ESP-WROOM-32. I've managed to fabricate the package/footprint part on Eagle if you're using eagle then I'll happily supply it for you to use. Below is the schematic I did for mine. You can power it us...
by InsertTitle
Tue Nov 21, 2017 10:34 am
Forum: Beginners
Topic: What are amp op / differential amp op? - What would be best for my project?
Replies: 10
Views: 1201

Re: What are amp op / differential amp op? - What would be best for my project?

Okay so let me get this straight everything before the the output of the op amp is fine. However this output would then go directly into a power amp which would then output directly into the headphone jack / speaker? Or should I look into just having a single chip which is a Power OP amp such as a O...
by InsertTitle
Tue Nov 21, 2017 9:23 am
Forum: Beginners
Topic: What are amp op / differential amp op? - What would be best for my project?
Replies: 10
Views: 1201

Re: What are amp op / differential amp op? - What would be best for my project?

A few extra things to consider. Do you want the headphone jack to be Stereo (left and right might have different signals) or mono (left and right will be exactly the same). If you want to have stereo in the headphones then the headphone jack needs to be before the circuit that makes the signal into...
by InsertTitle
Mon Nov 20, 2017 8:18 pm
Forum: Beginners
Topic: What are amp op / differential amp op? - What would be best for my project?
Replies: 10
Views: 1201

Re: What are amp op / differential amp op? - What would be best for my project?

I see I understand now. Extra question I'd like to ask. What general size resistors / capacitors would be used in such a design? Also I've noticed online including hippy's own design an singular op amp and then I've noticed ones with 2-3 in them. What's the difference in the increased number of 3 op...
by InsertTitle
Mon Nov 20, 2017 5:07 pm
Forum: Beginners
Topic: What are amp op / differential amp op? - What would be best for my project?
Replies: 10
Views: 1201

Re: What are amp op / differential amp op? - What would be best for my project?

Okay so if I get this right. The two pins from GPIO 40 & 45 would act as the 2 differential inputs which would go through an amplifier circuit and deliver a single output. This output would then attach itself onto the 2 pins of a headphone jack to produce the audio for the headphones? Then I simply ...
by InsertTitle
Mon Nov 20, 2017 9:43 am
Forum: Beginners
Topic: What are amp op / differential amp op? - What would be best for my project?
Replies: 10
Views: 1201

What are amp op / differential amp op? - What would be best for my project?

Before anything, I'm a newbie I do not have the best of knowledge and I'm going off what I've found so far but have got confused and need help. So I'm trying to wrap my head around analogue audio to use on the CM3. Now I know after some digging about that PWM (Pulse Width Modulator) particularly PW...
by InsertTitle
Wed Nov 15, 2017 5:52 pm
Forum: Networking and servers
Topic: Custom Compute module 3 - How can read in serial without USB?
Replies: 23
Views: 3286

Re: Custom Compute module 3 - How can read in serial without USB?

Okay I have a sense of understanding now from what you're talking about. The reason I'm talking bluetooth is for the likes of bluetooth headsets you the type like taxi drivers or businessmen wear on 1 ear. Part of my project is to detect objects and then feedback this back to the user via either hap...
by InsertTitle
Wed Nov 15, 2017 5:37 pm
Forum: Networking and servers
Topic: Custom Compute module 3 - How can read in serial without USB?
Replies: 23
Views: 3286

Re: Custom Compute module 3 - How can read in serial without USB?

Daft question regarding the flow control. If I wanted to be able to turn on / off the ESP via a button would booting it up be the same thing as the CTS/RTS as in I press the button to turn on the ESP and it will allow the data to flow into RTS/CTS whilst if I press the button again it will do the op...
by InsertTitle
Wed Nov 15, 2017 5:04 pm
Forum: C/C++
Topic: CTS & RTS UART
Replies: 2
Views: 1448

Re: CTS & RTS UART

Don't know if you found an answer to this yet but this might give you some aid
viewtopic.php?t=37203
by InsertTitle
Wed Nov 15, 2017 4:21 pm
Forum: Networking and servers
Topic: Custom Compute module 3 - How can read in serial without USB?
Replies: 23
Views: 3286

Re: Custom Compute module 3 - How can read in serial without USB?

Cheer, so simply put I connect TXD0 & RXD0 from the ESP into the the TXD0 & RXDO pins relative of the Pi Zero and of the CM3 when moving over to the CM3. What should I do about pins like IO13 & IO15 these would of originally gone into the CP2102 as RTS & CTS. Likewise Pin IO0 would work round into p...
by InsertTitle
Wed Nov 15, 2017 2:35 pm
Forum: Networking and servers
Topic: Custom Compute module 3 - How can read in serial without USB?
Replies: 23
Views: 3286

Re: Custom Compute module 3 - How can read in serial without USB?

Would that possibly the same GPIO pins as being reported on the ESP8266 link I posted? I don't know. That link appears to describe connecting a module in SDIO mode. Is that what you meant by "serial" ? Having mentioned CP2102 I assumed you meant UART-style serial. Yes CP21202 as in UART-style seria...
by InsertTitle
Wed Nov 15, 2017 1:41 pm
Forum: Networking and servers
Topic: Custom Compute module 3 - How can read in serial without USB?
Replies: 23
Views: 3286

Re: Custom Compute module 3 - How can read in serial without USB?

What I'm currently at the the moment is I'm developing the prototype on Pi Zero W & Pi Zero 1.1 but I'm also developing the custom board using Eagle. That should be fine. Once you have the ESP-WROOM-32 working when connected via the serial pins on the Pi Zero it should simply be the case of your CM...
by InsertTitle
Wed Nov 15, 2017 11:41 am
Forum: Networking and servers
Topic: Custom Compute module 3 - How can read in serial without USB?
Replies: 23
Views: 3286

Re: Custom Compute module 3 - How can read in serial without USB?

What I'm currently at the the moment is I'm developing the prototype on Pi Zero W & Pi Zero 1.1 but I'm also developing the custom board using Eagle. I'm aiming to get the circuit board completed on eagle so I can plan for when I move the design over from the Pi Zero to CM3. The only things left in ...
by InsertTitle
Wed Nov 15, 2017 11:06 am
Forum: Networking and servers
Topic: Custom Compute module 3 - How can read in serial without USB?
Replies: 23
Views: 3286

Re: Custom Compute module 3 - How can read in serial without USB?

I'm currently in the works of creating a custom I/O board I already have power supply (this connects to my sensors and the CM3 directly) and I2C completed. I have no need for HDMI nor Analog video as I'm not using any form of monitor display and currently working on audio working with op amp circuit...
by InsertTitle
Wed Nov 15, 2017 9:43 am
Forum: Networking and servers
Topic: Custom Compute module 3 - How can read in serial without USB?
Replies: 23
Views: 3286

Re: Custom Compute module 3 - How can read in serial without USB?

I'm just confused now. First and foremost I'm newbie coming into electronics simply put. All I want to achieve is to get wireless and bluetooth from the ESP-WROOM-32 working with the compute module 3 without the need to add in USB connectors nor use a UART to USB convertor such as the CP2102. Can th...
by InsertTitle
Wed Nov 15, 2017 8:44 am
Forum: Networking and servers
Topic: Custom Compute module 3 - How can read in serial without USB?
Replies: 23
Views: 3286

Re: Custom Compute module 3 - How can read in serial without USB?

Update. So I spoke with an electronics buddy of mine who came back with something like this:

https://oshlab.com/esp8266-raspberry-pi-gpio-wifi/

Would I be able to apply this in a similar fashion to the ESP-WROOM-32?

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