Close

Setbacks and font stuff

A project log for Insulin Minder

Helps keep track of how hot or cold my insulin has gotten and when I last had an injection. Great for the absent minded diabetic!

Linus DillonLinus Dillon 12/31/2014 at 00:290 Comments

Had a go at putting together an assembled version of the minder. My plan was to sandwich the battery, LiPo backpack and temperature sensor between the Trinket and the OLED, with the navigation button to the side of the display. All of it would be wired together using fine wires (wire-wrap wire in fact) so that I don't have another layer of PCB bulking it out. All a bit fiddly and I ended up not getting very far. To make it thinner still I tried to desolder the JST connector on the LiPo backpack and solder the battery leads directly to it (maybe not the best idea, but those JST connectors are fairly thick compared to all the other components). Instead I managed to kill the LiPo backback by lifting tracks on the PCB.

As a result I have (i) ordered some additional LiPo backpacks and (ii) am rethinking my approach to packaging of at least the first unit and (iii) have ordered a cheap hot-air rework station from EBay (have wanted one for a while anyway). I might just go with the "natural" method of mounting the LiPo backpack on top of the trinket as intended (other than the output from the backpack to the Trinket). I'll end up with a much fatter minder, but there will be less risk of it not working too. Note for Adafruit: how about a fairly bare-bones breakout board for that charger chip? One with no JST connector...

As I'm waiting on bits to arrive before jumping into hardware again I have instead done a little software work. As usual rather than trying to take the shortest path to having something working I'm adding bells-and-whistles. In this case support for better fonts on the OLED. To that end I have grabbed a nice small true-type free-for-personal-use font (Bit Daylong 11), converted it to C code (I found a Windows application to do this), and have written a function to print the characters (yeat to be tested, but all pushed to GitHub).

Discussions