Great to see there’s already been a couple of posts regarding suggestions for new smôl products. Also very interesting to hear about products yet to come.
Paul, we’ve chatted a bit about this and here are some of my suggestions as promised:
smôl microSD
This would enable a smôl-based project to log data to a microSD card. Ideally, power to the microSD could be controlled on-board via a P-MOSFET similar to the OpenLog Artemis and not an additional AP2112 regulator, like the MicroMod Data Logging Carrier Board.
smôl Inertial Measurement Unit (IMU)
A natural choice for the smôl ecosystem, though a particularly daunting one given current global chip shortages. In my opinion, this IMU board would not be based on the ICM-20948 or the BNO055/80, given the long history of issues, lack of support, and the number of grey hairs I’ve gotten dealing with these sensors. A more popular alternative could be STMicroelectronics’ industrial-rated ICM330DHCX and LIS3MDL, which I know have been working extremely well for some users.
smôl Real-Time Clock (RTC)
While many of the microcontrollers have on-board RTCs these days, not all of them are overly stable. Micro Crystal has released a very attractive RTC in the RV-3032-C7, which I also hope will be the successor to the Qwiic RV8803. This RTC has just about everything you’d need and only draws 160 nA. It supports charging circuitry, so the smôl board could incorporate the same supercapacitor as the RV1805 and ZED-F9P.
smôl Babybuck Voltage Regulator
Perhaps my greatest curse is needing to work with battery voltages greater than 6V (AP2112’s max input voltage). It’s great to see there are AA and LiPo power boards and I think a smôl board that allows users to make use of 9V and 12V batteries would be icing on the cake.
smôl u-blox ZED-F9P
A man can dream!
Happy to get feedback on any of these suggestions!
Thanks for all the great feedback - please keep it coming.
smôl microSD - yes this is definitely coming. I’m not sure yet if that board will be Artemis-based or STM32-based, or maybe we’ll do both.
smôl IMU - yes, this is definitely coming too. I haven’t ruled out the ICM20948, despite its complications. I haven’t ruled out the BNO08x either as we’ll be using SPI and most of the pitfalls with the BNO are related to I2C and clock-stretching. Thanks for the advice about the ICM330DHCX and LIS3MDL. I will have a good look at those.
smôl RTC - this would be a nice addition. I’ll put it on the list - thanks! The time-keeping (sleep duration) on the power boards will drift and it would be great to be able to periodically re-sync to RTC without needing to power up a GNSS.
smôl Buck - another good suggestion - thanks! The challenge will be keeping the sleep / quiescent current low, but we’ll see what we can do.
smôl ZED-F9P - not unless we cut the chip in half!
Thanks for your reply! Very exciting to hear of what’s to come.
Out of curiousity, do you have any thoughts on how to mount smôl boards? I’m trying to think of the best approach to secure several smôl boards, say inside an enclosure.
The brief for smôl was to keep the boards as small as possible. Adding any kind of mounting hole would have increased the size of the boards.
For wildlife tracking, the boards will almost certainly be encapsulated or potted. Mounting holes would be redundant there.
For some applications, quite seriously, 3M VHB double-sided tape would be the perfect solution. For others, a 3D-printed bracket or support might be more appropriate.
We will be adding two new FPCs shortly that will allow the boards to be stacked end-to-end (in a long daisy chain - think collar for animal tracking) or side-by-side (for reduced height).
On the mounting hole issue, it isn’t clear that something can’t be done. I’ve attached a photo showing a size comparison between Smol ESP32, ESP32 Thing Plus, and two boards from a competitor named “TinyCircuits” and their Atmega328P-based TinyDuino.
It’s not my purpose to shill for TinyCircuits, and indeed I can’t since they have skipped (and continue to skip) the whole ESP32 bandwagon, but their boards are small and have mounting holes.
There are several Atmega328P processor boards, one version has a USB-A connector, another version replaces the USB-A port with a battery connector and a slide power switch. This latter board has no circuits on the back side but does require purchase of a separate board for uploading code.
The TinyCircuit boards stack vertically, and the USB-A board doesn’t need to be part of the final stack. Some of the boards are larger than the processor board, like the OLED, audio output, etc., but most are the same size, and the stack is held together with the rectangular connector and little screws through the mounting holes.
Remove the USB-C port, replace with a detachable separate board.
Also, use a smaller LED.
Replace the antenna with a u.fl connector.
In the above photo, the area of the Smol as-is is approx the same as the TinyDuino boards. Remove the USB-C and there should be plenty of room for mounting holes.
