Let's talk of possible new accessory boards

Rezo said:
2. Another thing that I would find very useful is a general purpose carrier board for the MicroMods. The only way to use a MicroMod on a custom PCB is to obtain the M.2 carrier + standoff and have them shipped out to be soldered on, something that makes low quantity production very expensive
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I dunno'. If we are asking the Teensy to be a PC, why not just buy a PC, or an SBC, or a Raspberry?

I see the ARM MCU on a Teensy, as not quite a hard real time device like a DSP (because of the interrupt architecture), but still close enough to hard real time for usec time scale, and electronically it is bare access, essentially a carrier for the MCU with supporting circuitry to power it up and boot into a user program. Accordingly, Digikey lists the Teensy under evaluation boards.
 
Note some of these exist, but I’m thinking Teensy branded, and with dedicated libraries.

  1. Flash chip memory board
    1. a Winbond is fine but some board we can plug into PCB or solderless
  2. ADC expansion board (8 inputs)
    1. Offer low cost 12 bit board
    2. Offer precision 16 bit board
    3. Must have tri-state MISO built in (if needed)
  3. Wifi board
    1. One that can leverage WiFi.h, WiFiClient.h, WiFiAP.h, WebServer.h
    2. Connect via SPI or Serial?
    3. Basically a Teensy and this board and replace an ESP32
  4. Teensy with built-in Wifi
    1. Like #6 but a single board
  5. Offer a Teensy “Explorer” kit
    1. A box filled with 2 Teensy 4.0’s and a bunch of sensors, and things like a solderless breadboard and wires
  6. Teensy 4.0++
    1. 32 pin boards and change the 3v3 and GND pins on the end to 2 more analog/digital pins
    2. Still use the M7 chip
    3. DIP sockets cheap and easy to get
    4. gives us 6 more pins
  1. Cortex M7 based Arduino NANO
    1. Same pinout as a NANO
    2. Great for replacing Arduinos
    3. I get the 5v issue maybe built in level shifters
    4. I wonder how many would replace the crippled NANO for this 😊
    5. Maybe Cortex M7 based Arduino UNO as well?
  2. From a marketing perspective, contact (have an intern do this) every shield supplier on places like Amazon and make sure they list Teensy as well. Too many claim Arduino and STM compatible, but don’t mention Teensy.
 
Srx said:
Export hardware debugging.
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Yes, this!

It’s still OT, since it requires a change to Teensy 4.x and isn’t an accessory as such, but a jumper to temporarily disable the bootloader and some JTAG pads or castellations would be really useful.
 
Here's the list I was thinking of yesterday.
  • analog mux + pot-with-cable
  • high performance ADC chip (not audio focused)
  • higher quality audio
  • many channel audio
  • MIDI in / out
  • power over ethernet
  • battery power / management
  • single pair ethernet or ethercat
  • wifi
Now 27 replies later, so much more to think about.

Please keep commenting... about accessory boards. This isn't the place to talk of new or modified Teensy models. Please try to stay focused on accessory boards that would work for Teensy 4.0 and/or Teensy 4.1. We can and will talk of ideas for Teensy later this year, but right now the topic is accessory boards (which have been woefully lacking all these years).
 
KrisKasprzak said:
ADC expansion board (8 inputs)
  1. Offer low cost 12 bit board
  2. Offer precision 16 bit board
  3. Must have tri-state MISO built in (if needed)
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I'll volunteer for the 8 input 16 bit ADC expansion board on SPI. I have a design close to ready to go, just need a sponsor for parts and assembly.

It is based on the ADS8168, vref 2.5V to 5V (4V internal), 16 bit precision, SNR 92 dB, and it is avaiable in 250KSPS, 500KSPS and 1MSPS sampling rates.

Cost for parts is probably about $40 per board in low quantity, It is a 4 layer board about 40mm x 40mm.

Any volunteers to sponsor?
 
DrM said:
I dunno'. If we are asking the Teensy to be a PC, why not just buy a PC, or an SBC, or a Raspberry?

I see the ARM MCU on a Teensy, as not quite a hard real time device like a DSP (because of the interrupt architecture), but still close enough to hard real time for usec time scale, and electronically it is bare access, essentially a carrier for the MCU with supporting circuitry to power it up and boot into a user program. Accordingly, Digikey lists the Teensy under evaluation boards.
Click to expand...

Sorry, but where did I ask for a PC?
How is a T4.1 with PSRAM different to a T4.x with SDRAM? Its just a faster memory base suitable for more advanced usage with things like frame buffers for larger displays, image and audio processing.

I have a project that uses SDRAM for audio buffering and visual rendering - couldn’t do it on a T4.1 as PSRAM is way too slow
 
I second Paul's item
  • high performance ADC chip (not audio focused)
  • battery power / management
  • power over ethernet
lower priority
  • single pair ethernet or ethercat
  • wifi
 
One of the "use cases" I'm really hoping to address is the people wanting to build huge MIDI controllers with tons of analog pots, rotary encoders, switches. Or similar for audio synth projects where a large number of knobs or buttons control various audio settings rather than sending MIDI to a PC.

I'm pretty sure everyone on this forum has seen these messages where someone ran out of analog input pins and has trouble using a board like SparkFun's CD74HC4067 Analog/Digital MUX Breakout. That's why I'm hoping for something Teensy specific that requires less guesswork, and maybe has pot+wire+connector assemblies available so it's mostly "plug and play" to get a huge number of knobs wired up successfully.

If anyone has ideas about how to best meet this common need, enabling people with a lot of music background but struggling to get electronics working to successfully wire up many more pots than the limited analog inputs, please chime in. We get this question pretty regularly here. And long-term, I'd really like to write more tutorials and example programs around an easy-to-use piece of hardware that helps anyone easily connect more pots/knobs/switches.
 
I write as a relative novice. I would like:
1. A microcard that slots into the SDCARD hole and gives me access to all the extra pins.
2. Something to give me easy access to the underneath pins. [As a member of the International Organisation for The Emancipation of Disadvantaged Pins, I demand a better deal for Underneath Pins!]
3. Anything that will give me easy access to many more digital pins.
 
Rezo said:
Sorry, but where did I ask for a PC?
How is a T4.1 with PSRAM different to a T4.x with SDRAM? Its just a faster memory base suitable for more advanced usage with things like frame buffers for larger displays, image and audio processing.

I have a project that uses SDRAM for audio buffering and visual rendering - couldn’t do it on a T4.1 as PSRAM is way too slow
Click to expand...

Sorry, I was referring to the micromod.
 
Narrowboater said:
I write as a relative novice. I would like:
1. A microcard that slots into the SDCARD hole and gives me access to all the extra pins.
2. Something to give me easy access to the underneath pins. [As a member of the International Organisation for The Emancipation of Disadvantaged Pins, I demand a better deal for Underneath Pins!]
3. Anything that will give me easy access to many more digital pins.
Click to expand...

How about making underneath pins on top pins? There are custom teensy designs that do that, for example this one here: https://github.com/jenschr/Teensy-4.1-example

It is pretty fantastic.
 
Rezo said:
I have a project that uses SDRAM for audio buffering and visual rendering - couldn’t do it on a T4.1 as PSRAM is way too slow
Click to expand...

Actually, that happens to be super relevant for me at this moment. What sample rate are you able to reach for buffering with each of the two memory types?

Thanks

In case it is interesting, this is for acoustic holography, with lots of mems microphones.
 
PaulStoffregen said:
If anyone has ideas about how to best meet this common need, enabling people with a lot of music background but struggling to get electronics working to successfully wire up many more pots than the limited analog inputs, please chime in.
Click to expand...
Kinda thinking out loud here ... Major considerations would be minimal use of precious I/O, speed of scanning large numbers of controls, and CPU overhead. I've used the M5Stack encoder and pot modules, which provide 8 knobs plus RGB LEDs on the I²C bus. You could have a lot of those tomorrow, but I²C would be prohibitively slow for serious numbers. The idea most worth stealing adopting is that they're based around a small MCU (STM32 of some sort).

So perhaps a SPI-connected MCU, with multiplexers added, would do the job. Even if its onboard ADCs are a bit rubbish, for pots it may be possible to eke out a reasonable resolution, say 12 bits, by doing a bit of averaging. And the remaining GPIO could be used for buttons etc. - if the MCU code is open source, the world is the mollusc of your choice... An MCU with 4 ADC inputs and 4 16-way multiplexers would support 64 pots; that's (say) 64x16 bits of data to read, or 64µs at a modest SPI bus speed of 16MHz.

I would favour the RP2350 for this; the RP2040 has ADC problems, but I believe the RP2350 fixes those, and you also have the benefit of dual cores and the PIOs. It's also cheap and widely supported, including in Arduino.
 
PaulStoffregen said:
I'm pretty sure everyone on this forum has seen these messages where someone ran out of analog input pins and has trouble using a board like SparkFun's CD74HC4067 Analog/Digital MUX Breakout. That's why I'm hoping for something Teensy specific that requires less guesswork, and maybe has pot+wire+connector assemblies available so it's mostly "plug and play" to get a huge number of knobs wired up successfully.
Click to expand...

Paul, it seems pretty straightforward.

Some thoughts on the use case, a midi controller with lots of electromechanical controls, perhaps we could rapidly cycle through the lines and buffer the state of each channel in memory in the Teensy to create an array of virtual inputs.

For velocity sensitive controls, we need to look at the datasheet a little more closely, but it might be possible.

The other thing to think about, is that this particular analog switch/multiplixer gets you 16 analog lines at the cost of 4 digital lines plus one analog line. The Teensy of course already has 18 inputs, but just 10 on top.

A 32 line multiplexer gets you 16 more lines compared to that board that you mentioned, and at the cost of only one more digital line. Not bad. There are a few of those from Analog for example. So 10 lines from the Teensy can get you 64 inputs.
 
@PaulStoffregen

Unfortunately Paul my interest lies is not in MIDI/Audio. Most interested in graphics, robotics, imu's, data acquisition, speech and speech recognition, DSP - see the pattern, etc. ADCs/DACs are good since they can be used for other purposes than MIDI. Although wondering if a midi controller can be used for other purposes - maybe OSC?

Anyways, back to the question about add-on boards. A long time ago @brtaylor developed a series of add-ons or what he called backpacks for the T4 but could also be used for the T41 but they were a T40 form factor. Here is the link: https://forum.pjrc.com/index.php?threads/teensy-backpacks.53695/. From the first post:

Rich (BB code): 
Backpack Frame
Available in Solo and Double variants, the Teensy Backpack Frame allows you to easily mount your teensy and provide external power. Both variants have four 2-56 mounting holes and a screw terminal for accepting 16-28 AWG wire. The Double variant stacks two teensy footprints side-by-side, enabling you to use more backpacks with a lower stack height. Both frames have the option of adding power regulation, enabling you to use +6.5V to +36V input; perfect for powering your project directly from a 2S to 6S lipo battery.

Motion Backpack
Integrating an MPU-9250 inertial measurement unit and a BME-280 environmental sensor, this backpack enables you to easily measure your project's motion and altitude. You'll get 3 axis accelerometer, 3 axis gyro, and 3 axis magnetometer data along with pressure, temperature and humidity. Both sensors communicate over I2C, have integrated pullups, and you can select the I2C address for each sensor.

GNSS Backpack
Adds the uBlox SAM-M8Q multi-constellation GNSS receiver to your Teensy! The GNSS receiver features serial and I2C communication, a pulse-per-second (PPS) signal and LED, a CR1216 battery holder for extremely fast cold-starts, and can be mounted directly to the Teensy or detached to remotely mount the antenna with four 2-56 mounting holes.

ADC Backpack
Integrates two ADS1115 analog to digital converters for 8 channels of 16 bit analog input. Analog inputs are pinned at a 0.1” (2.54 mm) spacing along with power and ground for easy potentiometer integration.

PWM Backpack
Actuate your project with up to 8 PWM signals from Teensy with the PWM backpack! All channels are pinned for standard servo connectors. Power and ground are bused so you can use an ESC or BEC on one of the channels to provide servo voltage. Optionally, one of the signals can be used for SBUS input to receive input from any SBUS capable receiver.

SBUS Backpack
Same as the PWM backpack, but with 8 SBUS outputs with the option of using one of the output channels for SBUS input to receive input from any SBUS capable receiver.

CAN Backpack
Add CAN communication to your project with the CAN backpack! This backpack integrates the MCP2562 CAN transceiver with six 0.1” (2.54 mm) connectors including +5V power, signal, and GND.

RS-485 Backpack
Add RS-485 communication to your project with the RS-485 backpack! This backpack integrates the MAX485 RS-485 transceiver with six 0.1” (2.54 mm) connectors including +5V power, signal, and GND.

Flash Backpack
Add 128 MBytes of flash storage with the Flash backpack! This backpack integrates two Cypress S25FL512S flash memory IC’s. Perfect for high speed data logging and works with the Teensy SerialFlash library.

SD Backpack
Add a micro SD card with the SD backpack! This backpack integrates a micro SD card, power regulation, and level shifters to meet all your data logging needs.

Unfortunately they are no longer available but there are pictures in the thread - I do have a couple of them and they came in handy.


I know there has been interest in SBUS. Know there is some interest on IBUS as well. Know that he had plans for a HOPE transceiver module as well which would be could for transmitting data - which I know there are other options which would be nice to have a back pack for.

Mike


EDIT: Note sbus and gnss backpacks were really a add-on with connectors so devices could be attached.
 
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The backpack web site is "not found". it's really hard to compete in the same space as adafruit and sparkfun. The inexpensive boards are just too inexpensive.
 
mjs513 said:
@DrM
Yeah - unfortunately they are no longer available. Posted just as udead
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In terms of design, there is hardly any barrier at all to replacing them with something similar. But at $6/board and two other companies already dominating the niche, it is probably not a good use of anybody's time.
 
DrM said:
Paul, it seems pretty straightforward.

Some thoughts on the use case, a midi controller with lots of electromechanical controls, perhaps we could rapidly cycle through the lines and buffer the state of each channel in memory in the Teensy to create an array of virtual inputs.
Click to expand...
Or alternatively, put several cheap microprocessors, that each handle maybe 8 analog inputs, and each one communicates to the Teensy via a shared I2C, SPI, or UART line. Ideally you want communication only when something changes (sort of like the MCP23017 where there is a pin output that is raised when one of 8 pins had a state change). The idea is there is a signal that something has changed, so the Teensy doesn't have to keep polling.

I could imagine maybe a bunch of smaller boards, each with 8 inputs, and connected to the Teensy shield via something like a RJ45 or RJ11 cable. That way you can scale inputs, and if a particular set of 8 inputs is broken, you can toss it without having to rewire everything.
 
I know it's not a board, but TBH, selling Teensies with PSRAM already attached, simple as it is, would be a huge win for those of us with shaky hands
 
honey_the_codewitch said:
selling Teensies with PSRAM already attached, simple as it is, would be a huge win for those of us with shaky hands
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Good news, Proto Supplies sells Teensy 4.1 with memory chips and others parts added. Of course it costs more, but if you want those parts soldered for you, they do it.

In fact, PJRC's PSRAM chip page mentions the Proto Supplies soldering option near the top of the page (the 2nd blue link on the page), just below the link for the ApMemory APS6404L_3SQR datasheet.
 
What about something for industrial applications:
- 24V power input, (12-36 volts ideally) with lots of protection and filtering.
- RS485, with selectable 120ohms termination, for modbus
- CAN, with selectable 120ohms termination, for CANOPEN
- 24V I/O using ST chips
- connectors for stepper motor driver.
- connector for DC motor driver.
- connectors for encoders.
- connector for TFT display (ILI9341, ST7789,...)
- connector for touch
- connectors for remaining serial, SPI, I2C interfaces
- Ethernet

But mainly, a board where connector placement is not random, in order to fit a enclosure with rear connectors and front TFT/buttons/led/encoder
 
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