Chalked up reveries

Recently I bought a Nerf Retaliator for my son on his birthday. I was scouting thingiverse  for some accessories to print like Nerf Sight , then I came across  AmmoCounter Mk1 Scope Case  by  Nathaniel Deal . Ammo counter lets you specify the magazine size and it will count down as you fire each shot. It will let you know how many bullets are left at any point of time. It is particularly useful for rapid fire guns and guns with 12, 18 or higher capacity magazines. AmmoCounter Mk1 Scope Case  has a nice scope face which can accommodate two 7-segment displays, 2 push button switches and an on-off switch. It has a separate compartment for 9V battery, has openings to route the sensor wire and has removable tracks to put it on the tact rail. Over all a very well designed case.  I was really impressed with the counter and decided to build one for my son. Dart Counter mounted on top of the Barrel extension A small video with Dart counter in action ...

This is the first post of a series, the idea is to post about some easy to overlook things while designing and building embedded hardware and applications. This post in particular is about a relay board which is driven over I2C. I was getting unintentional spikes on my load which is connected to the relay. At office, we are moving from C to C++ and I am new to object oriented programming. Learning theory is all good, but from my experience, we learn something well when we try to use it solve real problems with real constraints. So I started a pet project to build an IoT board based on ESP8266. I know that if I need to get something done, I should aim for MVP (minimum viable product) but this being more of a learning exercise than a project which needs to be completed asap, I started designing a platform independent code base which I would be able to leverage for future projects. (more about this probably in a later blog) Coming back to the topic, this particular board i am working...

Turn around time as well as cost for getting PCBs made from a PCB house is pretty high, especially when you want to make a single board for a special project or as part of prototyping. Its even more frustrating when you realize that you have messed up some things in the design and you have to do another iteration. From some time now, i have started milling my own PCBs at home using a CNC machine which has worked our really well for boards with a reasonable track width. One of the things I struggled a bit in the beginning was exporting solder mask as SVG. I print the solder mask on a transparency paper and use UV curable ink to apply solder mask to the board. At home i dont have a way to put vias on double sided PCBs, I solder a small wire on both sides to make it act like a via. When exporting solder mask layer as SVG from KiCad, there is no option to tell it not to tent vias. It is available when exporting data as Gerber but not when exporting it as SVG.  Now this is a probl...