Why LLaMa Is A Big Deal

You might have heard about LLaMa or maybe you haven’t. Either way, what’s the big deal? It’s just some AI thing. In a nutshell, LLaMa is important because it allows you to run large language models (LLM) like GPT-3 on commodity hardware. In many ways, this is a bit like Stable Diffusion, which similarly allowed normal folks to run image generation models on their own hardware with access to the underlying source code. We’ve discussed why Stable Diffusion matters and even talked about how it works.

LLaMa is a transformer language model from Facebook/Meta research, which is a collection of large models from 7 billion to 65 billion parameters trained on publicly available datasets. Their research paper showed that the 13B version outperformed GPT-3 in most benchmarks and LLama-65B is right up there with the best of them. LLaMa was unique as inference could be run on a single GPU due to some optimizations made to the transformer itself and the model being about 10x smaller. While Meta recommended that users have at least 10 GB of VRAM to run inference on the larger models, that’s a huge step from the 80 GB A100 cards that often run these models.

While this was an important step forward for the research community, it became a huge one for the hacker community when [Georgi Gerganov] rolled in. He released llama.cpp on GitHub, which runs the inference of a LLaMa model with 4-bit quantization. His code was focused on running LLaMa-7B on your Macbook, but we’ve seen versions running on smartphones and Raspberry Pis. There’s even a version written in Rust! A rough rule of thumb is anything with more than 4 GB of RAM can run LLaMa. Model weights are available through Meta with some rather strict terms, but they’ve been leaked online and can be found even in a pull request on the GitHub repo itself. Continue reading “Why LLaMa Is A Big Deal”

A Studio Condenser Microphone For A Constrained Budget

As the Internet has turned so many of us into content creators, we’ve seen the quality of webcams and microphones steadily increase to the point at which even a fairly modestly-equipped YouTuber now captures their wisdom at a quality far exceeding that you might have found in some broadcast studios not so long ago. Still, decent quality costs money, and for that reason [Spirit532] has built his own high quality condenser microphone for less expenditure.

The capsule and body are off-the-shelf items — what he’s produced is the bias voltage supply and preamplifier. In both cases these are the interesting parts of a condenser microphone, so their circuit bears a second look.

The condenser microphone takes a diaphragm and turns it into one side of a capacitor. If you apply a charge to this capacitor, the voltage over it changes minutely with the capacitance as the diaphragm vibrates. Thus to have a usable audio signal level a high-voltage bias supply is required to provide the charge, and a very high impedance preamplifier circuitĀ  to catch the signal without draining the capacitor.

His bias supply is a charge pump using a string of diodes and capacitors fed by a chain of CMOS inverters, with an RC filter and resistor chain to provide that super-high impedance. The preamplifier meanwhile is a unity gain high-impedance op-amp with an inverting stage to provide a balanced connection. For good measure the circuit also includes a phantom power supply.

This is an interesting project for anyone with an interest in audio. if you’re further interested in condenser microphones, how about also looking at electret microphones?

Icicle Patterns With Custom Gantry

[Cranktown City] uses a number of custom-built linear rails used as gantries for various tools in the shop. The first is on a plasma cutter, which is precise but difficult to set up or repair. Another is for mounting a camera, and while it is extremely durable, it’s not the most precise tool in the shop. Hoping to bridge the gap between these two, he’s building another gantry with a custom bearing system, and to test it he’ll be using it to create patterns in icicles hanging from an eave at his shop.

While this isn’t the final destination for this gantry, it is an excellent test of it, having to perform well for a long period of time in an extremely cold environment. The bearing system consists of a piece of square steel tubing turned 45Ā° inside another larger square steel tube and held in place with two sets of three bearings with V-shaped notches. To drive the gantry he is using a motor with a belt drive, and for this test a piece of drip irrigation is mounted to it which lets out a predetermined amount of water on top of the roof to create numerous icicles beneath with various programmed lengths.

After a few test runs the gantry system can create some icicles, although they don’t have the exact sine wave shape that [Cranktown City] programmed into it. They are varying lengths though, and with no more cold days in the forecast he’s called it a success. This isn’t the final destination for this robotic linear gantry, though, but it did help him work out some of the kinks with it beforehand. For other sources of inspiration, take a look at this linear rail system also used for driving various robotic tooling.

Continue reading “Icicle Patterns With Custom Gantry”