Simplight and prototyping

I started working on a new project tonight.  I’m going to build a compact, cheap LED light that runs on a single AA battery.  I’ll be using the MCP1640 voltage regulator booster from MicroChip.

I created the Eagle-Layout for it tonight and ordered a test board from OHSPark to verify the layout.  I also created a SOT23 to breadboard adapter and ordered 3 of those as well.  That will make it easier to prototype the chip and figure out how to set it up.

I also made a variant of the TO92 package for Eagle.  I find it annoying to bend the pins for transistors when putting them in boards.  I can’t think of a good reason it’s needed so I built a straight layout for the BC517.  I added it to the test layout board that I ordered.

MCP1640 breadboard adapter

MCP1640 breadboard adapter

Test board to verify component layout.
Test board to verify component layout.


TinyTimer-KS Developments

I spent some time tuning the TinyTimer design with the interface.  I realized I wasn’t happy with simple pins for the input and logic connection points.  I changed them to terminals which set off a cascade of space issues.  I wound up re-laying out the entire board this evening to deal with some space constraint issues.

Added a top layer ground plane to resolve some ground plane issues.  Incorporated some best-practices settings from Sparkfun to increase manufacturing tolerances by setting higher separation values.

The big change is that I put the LED driver at the top of the board to isolate all of it’s traces and get them out of the way.  The input buttons moved to the bottom of the board where they are easier to manage.  The run/program jumper moved to the other corner.  It will be important for people to disconnect the load before programming.

TinyTimer Candidate

TinyTimer Candidate

Yet Another Revision to TinyTimer-Classic

Found an issue with the ISP and while I was fixing it I realized I could free up a pin to add an input.  There is very little cost involved with adding the input which is a great thing.  It significantly increases the things you can do with the timer by allowing it to react to an external input.

Change Log:

  • added 2 pin terminal block for input via an Analog pin on TinyTimer.
  • labeled load and input terminal blocks.
  • connected input terminal block to VCC (5v) and a 100 ohm resistor -> ADC 3.
  • Moved RED led off the serial clock line. It was causing the ISP to not work properly.  Validated by cutting one lead on the prototype.
  • Adjusted some component locations for easier assembly.

Here are some images related to the changes and improvments:

board-layout-tiny-timer Tiny-Timer-board-layout schematic-tiny-timer-classic-v8