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There is also the need to properly load the phono cartridge of your turntable for flat response. The Moving Magnet (MM) cartridge may need 47K with 250pF termination. Does the audio preamp have the...

Many years ago I did a student 'work-week' for a quartz crystal (oscillator kind) manufacturer. My first task was to measure the resistance of these tiny bead thermistors that were to be placed...

The OP has an interesting project going that I'd like to learn from.


In an AudioXpress (April 2007) edition, Dennis Colin had a project that used a couple of LSK389 in parallel whose output was...

I too was looking for an R/C transmitter-receiver for a small rover. A friend uses one similar to this;...

I've worked on an organ that used a cylindrical magnet in the end of each pedal and a reed switch would close a contact when the pedal was depressed. Here is one idea;...

Ok, that project/link can help you. The link uses an UNO but you could also use a Teensy but the pin numbers may be different. I haven't used my Teensy yet thus can't guide you in substituting the...

Yes, a Teensy can do it.
Have a look here; https://learn.adafruit.com/midi-solenoid-drummer/overview

Yes, the series resistance can cause a slow start-up or "sleepy crystal". I found this article helpful, https://www.electronicdesign.com/analog/fundamentals-crystal-oscillator-design

Where did you see the 250ma current spec? On page 6 I found 25ma.(https://www.nxp.com/docs/en/data-sheet/K66P144M180SF5V2.pdf)
Not familiar with the Teensy regarding slew rate control.

The...

Somebody might be able to help, but first; "Always post complete source code & details to reproduce any issue!"

I wasn't able to make my circuit simulation malfunction using the pulse width values you gave. So, perhaps I'm not simulating it correctly? I wonder what your scope output does look like using this...

I'd be interest to see a 'scope shot of a data stream including your sync. Apparently LTSpice has a way of using a data file to stimulate the circuit so one can see what the output would be with such...

Before you connect a CD4050, try to see if there is a negative dc level in your output. My data sheet says not to go below 0.5V input. As Paul mentioned its possible to shift the dc point via...

Perhaps you have. How about using an AC coupled circuit with clamping diodes and an emitter follower, like below? You can fiddle with the values to get a good waveform. I use LTSpice for a quick...

I didn't do any testing, but drew the diagram to provide a proof of concept. Your selection of a high speed opto is better since it is designed to work with 3.3V.
The 330 ohm was an arbitrary value...

That opto is too slow. I was thinking of a 6N137M. You may need to fiddle with the resistor values to get the desired rise/fall times. Also, it is uncertain as to how much delay this circuit produces...

I wonder if a 6N137 optcoupler would work as your level shifter. It may work at 3.6V for Vcc, although the datasheet says 4.5V minimum. It would provide ground loop protection for your keyboard.

Glad to hear its working for you.
Further refinements could include an autoranging circuit to bring the shunt voltage closer to the maximum analog input of the Teensy, but you may not require such...

What voltage do you measure from either two wires and ground when the battery is charging, or when the equipment is run from battery only?
Your planned circuitry will need to compensate for this...

I still have one of those clocks.

You need to isolate the motor voltage or current that you wish to analyse. This can be done via a suitable transformer, or an isolation current to voltage transducer (hall effect device?), along with...

Does your tuner have a means to determine how many cents it's off, or be able to set it to x-cents off?

Years ago I worked with an organ technician who had a "home built" organ tuner that showed...

Hard to say with no actual hardware (or schematic) in front of me. If all the "ducks" need to be aligned precisely before it works I would expect a timing issue somewhere, or faulty code. Decoupling...

Thanks Theremingenieur.

What values do you recommend?

Sorry, ... beginner's oversight. I didn't scroll down far enough, where the pots are read and thus connected.

Looks like an interesting project. I don't see where you connect the pots to the Teensy in your code.

I was dabbling with PID V1 a couple of years ago using an Arduino UNO with a standard 16MHZ clock. My notes said that PID.compute() took 80 usec. The default myPID.SetSampleTime () is 100 millisec....

I'm interested in how you made/cut the panel for the switches and the labelling. I often don't get past doing "a proof of concept" because of a lack finishing details and equipment. Thanks.

Peter.

Also see this for a direct connection to an 8X8 RGB module, https://github.com/marcmerlin/LED-Matrix/

How about the CD4511? https://www.digikey.com/product-detail/en/texas-instruments/CD4511BE/296-2072-5-ND/67341

No, not yet. It may be awhile before I get to an audio teensy project, as I have a number of other projects on the go.

I use this unit for similar reasons for my headphone listening/testing of various audio devices. It has a gain switch for selecting High and Low to cover most situations.

The datasheet says minimum 3.5V swing, but typically 4V swing, for a 5V DC supply.
I'd use a 3.3V power supply and then evaluate what the MSGEQ7 is not doing so well at 3.3V.

Thanks, Paul.
I thought that it might have been removed due to some incompatibility with the new Lib, meaning that "NewPing" couldn't be used.

Libs removed: NewPing.
Is there a substitute for those wanting a "NewPing" function?
I am in the process of building a 2WD Arduino rover with an Ultrasonic sensor. I'm currently planning to use an...

I could only find this which is for an Arduino, but you may be able to use your Teensy 3.6 board too. I don't have the changes you would need to make.

Thanks for the link. I'll take a look.

Hmmm.... I may become interested in this project. Our church has an old Johannus OPUS 1100 organ that has a MIDI out only, which no one uses. I've often wondered what that port provides. Maybe just...

It isn't clear to me what you consider to be "a good idea", as I don't clearly know what this project is connected to. Simply connecting your 3.5 mm jack to an analog input is too simplistic, and not...

Could there not be a DC bias on the probes? I would agree that the right-side diagram of yannick's schematic uses AC coupling to avoid such a DC. The article I linked in a previous post (#48) also...

Jumping in here, rather late ....
I'm not fond of your electrode - Teensy interface. I would prefer using a "instrumentation amplifier" chip.
Also, this article...

Thanks.
No its not a serious issue, just an observation on my part. It wouldn't significantly change the total current as most of the current is consumed by the IC.

I'm not a frequent viewer here, but I don't know what a "chamberlain" filter is. I do know about the biquad.

Did your stepdad work on vacuum tubes?
The resistor values of your opamp circuit...