Let's talk of possible new accessory boards

[DrM]

Should add high performance DAC (also, not audio focused).

High performance (probably at least 16 bits up to 20 bits, and 1MSPS) means you also need some analog circuitry on the board.

For range it should probably be 0V to 4V. So add an LDO, voltage ref and one of those small negative voltage ICs.

To really get performance close to 16 bits (or 20 bits) requires a pretty detailed design effort. But we can certainly do that.

On the other hand, there are cheap 16 bit boards. They seem to be just a bare ADC, they are slow (under 1KSPS) and actual performance could be 8 to 10 bits with the noise. But they sell for $6.

Are there enough customers for a board that really does give 16 bit performance, at 1MSPS? And would they buy it if it costs say.. $60?


I have a few designs that go futher, +/-4V range, very high impedance, 16 bits at 1MSPS. It is posted to github, and it is fantastically useful for a lab. But I am not aware of it getting a lot of traffic. I know that there are many people who use cheap usb modules and dont really appreciate the difference.

For those who are interested, here is the github. The CCD boards (Hamamatsu and Toshiba) , instrumentation input have all been built.

https://github.com/drmcnelson

I am thinking to build the photon tagging system next. That would enable researchers anywhere to be able to do fluorescent lifetime studies. A sponsor for parts would help.

 

[BlueSun]

The project I am working on now has become something of a Teensy 4.1 motherboard. Specialized for what I need, but a generalized one might be useful in several ways. Teensy 4.1 has a large number of IO, but a single accessory could preclude using any others. So why not make an accessory that permits multiple accessories without requiring jumper wires.

Basically what I'm describing could be as simple as a PCB with header locations (with or without headers pre-soldered, but ideally not) positioned and organized to permit a Teensy and several accessory boards to be attached. Not a typical breakout board. Not an Arduino form factor. Instead, header location(s) for specific functions like I2C. And one for WiFi/Ethernet. One for Power/Li battery management. One for Qwiic connectors. And so on. Maybe some headers are incompatible for use at the same time, but users can decide what accessory mix they want.

Some possible benefits:

• As a simple PCB with no components, it would be CHEAP. More than one version is possible if there is uncertainty what would be the ideal board design.
• The benefit for Sparkfun would be an increased compatibility with existing accessories and maybe make development of a new accessory less dependent on the existing pin-out or form factor of the current Teensy. i.e. A board each for T4, T4.1, and eventually T5. And one for Arduino Nano? ESP? RPI Pico? Micromod?
• Simple system development for some users. Instead of having to simultaneously run wires correctly for power and IO AND find code snippets to work with that accessory hooked up that way, online instructions and code snippets can include comments that indicate how to just plug and go.
• A more advance board could include some simple components. i.e. USB-C port for power and power management/battery charge chip. Level shifters?
• People could design custom boards derived from the base PCB design with some confidence on performance and accessory compatibility. My use case is a good example: I use OctoWS2811, level shifters, and an RTC with battery, but need these functions physically in particular locations. Intial prototypes with a standard board permitting all of these as plug in accessories would have been great (jumper wires worked, but was chaotic). Then leveraging the standard board and accessory designs, I could have created a production board that fits my particular use case much faster.

As for particular accessories, I would love to see:

1. USB-C power with power/charging management chip + Lipo battery connector
2. 802.11ah Wifi HaLow module