McMaster-Carr Shipping Costs
It’s not easy to find concrete examples of shipping costs for McMaster-Carr online, and they don’t tell you what an order is going to cost to ship until after it’s already shipped — and that can be a little scary…
Tag geek
StickBot – Building the Right Eye
Well, I discovered that Popsicle is a brand name, so I’m officially renaming this little guy “StickBot” so the Popsicle police don’t come after me. To be clear, this little bot has nothing to do with Popsicle brand ice pops,…
A Hackable 12-Channel Bidirectional Logic Level Shifter/Translator
Here’s a video of my very hackable 12-channel logic level shifter/translator with a voltage regulator. This video demonstrates how it works. There’s more detail here at the post. In this example, it’s translating from 7.5V to 3.3V. In another example…
How to Trim 40-Pin Female Headers
40-pin female headers are inexpensive and easy to trim down to size, and with a dot of CA glue (super glue), you can even easily make other configurations, like 2×4. Sometimes they’re even described as “break-away” headers, although admittedly they…
J&M SCR Robot Test-drive
He we’re test-driving the our latest robot creation for the first time. It’s the boy’s design and made mostly of wood. The tires are o-rings, and there’s a 12V AA batter pack sandwiched between the two pieces of plywood. The…
DIY 12-Channel Bidirectional Logic Level Shifter
Here’s a 12-channel bidirectional logic level shifter with a 3.3V power regulator that I designed so I could easily interface 5V circuits with cool 3.3V widgets like the ADXL345 accelerometer, the NRF24L01+ wireless transceiver, and the Nokia 5110 84×48 LCD. For the…
KiCAD / eeschema “Component Load Error”
I used the excellent Quick KICAD Library Component Builder recently to build a new component for eeschema in KiCAD, but when I imported the library, I got an error dialog that said, “Library component load error error <error <pin only…
SeeedStudio PCB Turn-Around Time (Registered Mail)
Before I placed my order, I had questions about Seeed Studio Fusion PCB service turn-around time for shipping to the USA, and so I figure others might as well. Here are details of my order of the ten 5cm square…
Fun With Reuleaux Triangles
Math Monday came early this week, and we had some fun exploring Reuleaux triangles. Next to a circle, they’re the simplest curve of constant width you can make — that basically means you can roll a plank on top of…
Arduino-compatible GI-SP0256-AL2 Speech Synthesizer
Here’s an Arduino-compatible GI-SP0256-AL2 speech synthesizer module that I’m finishing up. It’s a great 1980’s-era allophone speech synthesizer chip that was used in Intellivision expansion modules and sold at RadioShack stores for years for about $12. You can still find…