usb

The Raspberry Pi makes a great USB webcam for $100

There are many Raspberry Pi projects where I spend a few hours (or dozens of hours) building something with a Pi, and realize at the end that not only could I have purchased an off-the-shelf product to do the same thing for half the component cost, but it would work better too.

But this is not one of those projects:

Pi Webcam on Tripod - Pi Zero W and HQ Camera

The Raspberry Pi and its HQ camera make a surprisingly potent webcam, and if you want to cover the basics, and rival the image quality of all but the highest-end dedicated webcams, you can do it for under $100.

Still frame grab from recording on Dell XPS 13 using Raspberry Pi Webcam

Above is a single frame from a recording I did with the HQ Camera on my Raspberry Pi Zero W connected as a standard USB webcam using the Camera app on Windows 10 on my Dell laptop.

USB 2.0 ports not working on the Compute Module 4? Check your overlays!

Out of the box, to conserve power, the new Raspberry Pi Compute Module 4 doesn't enable its built-in USB 2.0 ports.

Compute Module 4 IO Board USB 2.0 ports are disabled by default

You might notice that if you plug something into one of the USB 2 ports on the IO Board and don't see it using lsusb -t. In fact, you see nothing, by default, if you run lsusb -t.

To enable the USB 2.0 ports on the Compute Module 4, you need to edit the boot config file (/boot/config.txt) and add:

dtoverlay=dwc2,dr_mode=host

Then reboot the Pi. Now you should be able to use the built-in USB 2.0 ports!

How to flash Raspberry Pi OS onto the Compute Module 4 eMMC with usbboot

The Raspberry Pi Compute Module 4 comes in two main flavors: one with built-in eMMC storage, and one without it. If you opt for a Compute Module 4 with built-in eMMC storage, and you want to write a new OS image to the Compute Module, or manually edit files on the boot volume, you can do that just the same as you would a microSD card—but you need to first make the eMMC storage mountable on another computer.

This blog post shows how to mount the eMMC storage on another computer (in my case a Mac, but the process is very similar on Linux), and then how to flash a new OS image to it.

Preparing the IO Board for mounting

Before you can set the eMMC storage into 'USB mass storage' mode, you have to put a jumper over the first set of pins on the 'J2' jumper—the jumper labeled "Fit jumper to disable eMMC boot":

J2 jumper for fit to disable eMMC Boot Raspberry Pi Compute Module 4 IO Board

Raspberry Pi USB Boot - UASP, TRIM, and performance

In the past few weeks, I reviewed USB drive performance on the Raspberry Pi 4, and the importance of UASP support for USB drive performance.

Both posts generated great discussion, and there were three things I wanted to cover in this follow-up, namely:

  1. Which drives support UASP
  2. Real-world performance benchmarks
  3. TRIM support

For reference, here are all the products I'm testing in this post (product links are to their Amazon product page, starting from top middle, clockwise):

USB Performance testing - SATA SSD, NVMe, and Flash drives

Enabling TRIM on an external SSD on a Raspberry Pi

I've been doing a lot of benchmarking and testing with the Raspberry Pi 4 and SSDs connected via USB. I explored UASP Support, which USB SSDs are the fastest, and I'm now booting my Pis from USB SSDs.

Anyways, one thing that I have wondered about—and some people have asked me about—is TRIM support.

I'm working on a new video for my YouTube channel that will go into some more detail on which of the drives I tested support TRIM, but while I was researching for that video, I also found that TRIM support in Linux is not as simple as it seems at first glance—it's definitely not plug-and-play, in my experience.

While internal microSD cards seem to support TRIM out of the box, none of the external USB drives I tested supported it out of the box. They all needed a little help!

The fastest USB storage options for Raspberry Pi

For years, I've been maintaining benchmarks for microSD cards on the Raspberry Pi, but I only spent a little time testing external USB storage, due to historic limitations with the Pi's USB 2.0 bus.

But the Pi 4 cleared away the limitations with a full-speed USB 3.0 bus offering much better performance, so I've done a lot of testing with USB boot, and with all the USB SSDs I had at my disposal. You can see some of those results in this blog post and video on booting a Pi 4 via USB.

After posting my tests concerning UASP support in USB SATA adapters, I got an email from Rob Logan mentioning the performance of some other types of drives he had with him. And he even offered to ship a few drives to me for comparisons!

There's also a video that accompanies this blog post, for the more visually-inclined:

UASP makes Raspberry Pi 4 disk IO 50% faster

You can view a video related to this blog post here: Does UASP make the Raspberry Pi faster?.

A couple weeks ago, I did some testing with my Raspberry Pi 4 and external USB SSD drives. I found a USB 3.0 SSD was ten times faster than the fastest microSD card I tested.

In the comments on the video associated with that post, Brad Manske mentioned something I never even thought about. He noticed that I had linked to an Inateck USB 3.0 SATA case that didn't have UASP.

What's UASP, you might ask?

I'm booting my Raspberry Pi 4 from a USB SSD

September 2020 Update: USB boot is out of beta! Check out this video for simplified instructions. All you need to do now is run sudo apt-get dist-upgrade -y, then reboot, then your firmware should be up to date. Now, flash any USB drive with the latest Raspberry Pi OS, plug it into your Pi (unplugging any microSD card), and you're off to the races!

Recently, the Raspberry Pi Foundation announced a USB boot beta for the Raspberry Pi 4. For a very long time, the top complaint I've had with the Raspberry Pi is limited I/O speed (especially for the main boot volume). And on older Pis, with the maximum external disk speed limited especially by the USB 2.0 bus—which was shared with the network adapter, limiting its bandwidth further—even USB booting didn't make things amazing.

Flashing a Raspberry Pi Compute Module on macOS with usbboot

I recently got to play around with a Turing Pi, which uses Raspberry Pi Compute Modules to build a cluster of up to 7 Raspberry Pi nodes.

Turing Pi Raspberry Pi 7 nodes of Compute Modules

Interested in learning more about building a Turing Pi cluster? Subscribe to my YouTube channel—I'm going to be posting a series on the Turing Pi and Rasbperry Pi clustering in the next few weeks!

You can buy Compute Modules with or without onboard eMMC memory. If you don't have memory, you can attach a microSD card and boot from it, just like you would on any Raspberry Pi model B or model A. But if you have the eMMC memory, it's nice to be able to 'flash' that memory with an OS, so the compute module uses the onboard storage and doesn't require a separate boot device (either microSD card or USB disk).

Review: AUKEY 30,000 mAh USB-C Portable Charger (with USB A, USB C, Micro USB)

Jeff's Rating: 3/5

tl;dr: Slightly pricey, could use a better interface for charge status, and holds 20% less than the advertised capacity, but the still-plentiful amount of stored energy and the ability to charge via USB-C or USB-A makes this a versatile and potent power pack for the price.

Ever since the mid 90s, when I was able to lug around 'power bricks' with my then-amazing PowerBook 190 and 180c (hand-me-downs from relatives), I've been hoping for a reasonably-priced power brick that would double my laptop's battery life, affording me the ability to work all day even when I'm doing a ton of crazy things, like building a ton of VMs and Docker images.

AUKEY 30000 mAh Portable Charger