#06. Electronics Design

Redesigning Echo Hello-World

This week we had to add a LED and a button to a well knowned board named Echo Hello-World. But, because is always good to have more work them the one we were asked to do, i decided i should use not one but three LEDs. This way, my board wouldn't just blink, it would glow.

Started with understanding the board, and how it would work, what did what, what goes where, etc etc (picture above). Getting sure that the routes where correct was the first thing, and since there were a coupple of free pins on the Attiny45 i wanted to use them to add some extra LEDs. The components to add were 3x100ohm resistors for 3xGreen LEDs and a 10kohm resistor for the button. Below you can check the full list of components i used:

  • R1 100ohm
  • R2 100ohm
  • R3 100ohm
  • R4 10kohm
  • R5 0ohm
  • R6 10kohm
  • C1 1uF
  • LEDs Green
  • Button
  • Resonator 20Mhz
  • Attiny44
  • ISP
  • FTDI
After looking into the diferent circuit drawing softwares and ended up using Eagle from Autodesk, never used this sort of software but since one of my goals is to make my own 3D printer eletronics i believe this would be one of the most useful tools. Started with searching for some tutorials and found a couple of them who were very useful, here's the link to them. With just the first two i was able to learn all i needed to redraw the board as i wanted.


As seen in the image above i used the method of linking the components by the use of small links with tags, this way there isn't a mess of wires going all around. To do this first you need to create a small piece of wire (net), then change the "name" and lastly use "label" to make the name visible. Also, add the "value" and then use label again just to be more understandable. The main difference in my circuit is the 3 LEDs i've added and the 0 ohm resistor that will be used as a bridge without wish i wasn't able to make all the routes. After i switch to the board mode, in here i've used "route" to make the routes and basic move/rotate. It took some time (almost a day considering that i had to redo everything once due to a simple mistake) to get everything to work out correctly and all routes got to the right place, at the end i only had to space out some resistor pads since there wasn't enought clearance between. Here's the end result:


Finally used the Carvey with the Easel app and carved the board away, this time did only the outlines of the path (with 0.1mm of depth) to tryout and workout really good, clean look, a fraction of machining time as well as less stress on the tool, to cut to board i've used outline again but this time with 1.7mm depth. Afterwards i just sanded it a bit and brushed with some steel wool to make it shiny. Soldering came afterwards and all went well with just some dificulty of the resonator. Below there's an image of the completed board and the schematic i made to help me put all together.


Files to download:

Multiple files