I recently acquired a LilyGO T-Deck, printed a cyberpunk-inspired case for it, and installed a 2000mAh battery so that I could run uLisp on. It works well enough, though I much prefer the PicoCalc's formfactor. That being said, it's nice to have a well-supported known-good platform to develop against. I also really like the visual doc-browser somebody on the forum posted.

One thing I thought would be neat would be to measure how long the battery life is. An extension I've been building in on every platform is the (now) function provided in the examples, and I found a forum post that includes a function for this. I wrote a quick "burnout" function (to burn out the battery) that looks like this:

(defun battery-status nil
 ; the t-deck is the only platform I have battery
 ; status working on.
 (if (eq *platform* :t-deck)
  (list
    (cons :battery (battery))
    (cons :time (now)))
  (list (const :time (now)))

(defun burnout nil
 "(burnout)
Burn out the battery: loop forever (until you run out of power)
running a benchmark cycle, then writing battery status and
run time."
  (loop
    (benchmark)
    (with-sd-card (str \"bench.txt\" 2)
      (print (battery-status) str))))

It returns an assoc list with :time containing how long the test ran for and on the T-Deck, :battery to show the final voltage. I probably should have made it append to the file, but as it is, I record only the very last entry. The burnout function loops, running a benchmark suite and writing the current battery-status to the SD card. Essentially, I want to know the battery life of a fully active uLisp machine. For the T-Deck, I turned on the keyboard backlight, and on the PicoCalc, I turned on the backlight to level 2 and added two levels of brightness to the screen. Not surprisingly, with a pair of 3200 mAh INR18650-33v batteries, the PicoCalc lasted quite a bit longer.

• T-Deck: ((:battery . 2.92059) (:time 5 33 56)): roughly 5h35m given the time it took to get the benchmark started.
• PicoCalc (overclocked to 200MHz): (:time (16 0 41))