Nicola Cimmino

Since I released the PLC14500-Nano, I received several questions on the choice of adding a pulse generator to shape the MC14500 W line. I decided to collect here my thoughts on the issue. I hope it can help shed light and, perhaps, help others design a similar system. The Write line, quite unsurprisingly, plays a role in the execution of STOre instructions. When asserted, this line indicates the MC14500 wants to write the value in RR, available on the D pin, to whichever I/O address is currently selected by the instruction parameter. The principle is simple: drive any output latch so that it stores D when W is asserted. Let's see in detail how this is implemented on the PLC14500-Nano. Below you can see the program counter is clocked by X1. If we look at the datasheet of the 74HC590A, tying CPC and CPR together causes the output on Q0-Q7 to increase by 1 on each positive edge of the clock. Keep this fact in mind: the address on the A0-A7 lines changes on the positive edge of X1.  S...

I often infuse various types of Japanese green teas. High grade teas are usually steeped several times, using different amounts of water and temperatures at each infusion. For this reason I wanted to create a marker that would allow me to keep track of the infusions. This could prove particularly useful in tea-tasting sessions, where multiple teapots can be in use at the same time to compare different types of tea. In this scenario a marker for each teapot would make it much easier to keep tabs on the infusions. I made several prototypes and toyed with many ideas. At first I 3D-printed with PLA several variations of tiles, of various sizes, some of which could be stacked and even clicked together like construction blocks. Each tile had a number, from 1 to 5. I knew I wanted the final result to be wooden, but 3D printing was the fastest method to prototype, at least as far as my skills and tools arsenal go. The tiles felt cumbersome though, as those not in use would need to be scatte...

You might have made the mistake in the past, you built a webpage for a personal website or for a business one and, wanting to be contacted by your visitors, you included your email address. Soon after you started to receive a deluge of emails, of course not from visitors, but from spammers. The issue of bots scraping websites for email addresses is as old as the web and, throughout the years, various escamotages have been employed to prevent this. The effectiveness varied as did the user experience when the user wanted to use that email address. Some of the most common are to use an image that contains the actual email address text or to escape the @ with something like [at]. The first approach works well but leaves the user to painstakingly copy the address as, obviously, including it in a mailto link of the image would defeat that purpose of having an image. The second at least allows the user to copy the text, which is extremely helpful if your email contains something like fre...