An Open Source Lead Tester

If you’ve ever needed an example of colossal failure of government actors, you need only to look at Flint, Michigan’s water crisis. After the city of Flint changed water supplies from Detroit to the Flint river, city officials failed to add the correct corrosion inhibitors. This meant that lead dissolved into the water, thousands of children were exposed to lead in drinking water, a government coverup ensued, [Erin Brockovich] showed up, the foreman of the Flint water plant was found dead, and the City Hall office containing the water records was broken into.

Perhaps inspired by Flint, [Matthew] is working on an Open Source Lead Tester for his entry into the 2016 Hackaday Prize.

[Matthew]’s lead tester doesn’t test the water directly. Instead, it uses a photodiode and RGB LED to look at the color of a lead test strip. These results are recorded, and with a bit of a software backend, an entire city can be mapped for lead contamination in a few days with just a few of these devices.

One problem [Matthew] has run into is the fact the Pi does not have analog to digital conversion, making reading a photodiode a little harder than just plugging a single part into a pin header and watching an analog value rise and fall. That really shouldn’t be a problem – ADCs are cheap, especially if you only need a single channel of analog input with low resolution. [Matthew] is also looking into using the Pi webcam for measuring the lead test strip. There are a lot of decisions to make, but any functional device that comes out of this project will be very useful in normal, functioning governments. And hopefully in Flint, Michigan too.

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USB-less WiFi For The Pi Zero

Since the introduction of the Raspberry Pi Zero, the hacker, maker, and hobbyist electronics world has been thrown into turmoil. ‘The Raspberry Pi Foundation is corrupt,’ the detractors said, ‘and the Pi Zero is just a marketing ploy to get their name out.’ Others chimed in that the Raspberry Pi Zero doesn’t even exist. Despite what a million monkeys on a million keyboards say, the Raspberry Pi Zero does exist and is very cool, despite how limited it is. There’s only one USB port, but that doesn’t mean you can’t have WiFi. [ajlitt] came up with a WiFi hat for the Pi Zero that goes right through the GPIO pins, and shouldn’t cost more than a few dollars to implement on any Raspberry Pi.

There is no Ethernet port on the Pi, and apart from a single USB OTG port, no apparent high-speed interfaces to the outside world. On the other hand, there’s a few things hidden deep down in the SoC on the Pi including two MMC controllers. One of these controllers is used for the SD card, but the second can be broken out on a few GPIO pins. By tapping into those pins and configuring the kernel just right, SDIO is available on the GPIO pins, giving the Pi WiFi through a cheap ESP8266 module.

We’ve seen [ajlitt]’s work on SDIO devices on the Pi before, but he’s slowly been reworking this build with the Pi Zero in mind. It didn’t begin as a project for the Hackaday Prize, but already it’s one of the more popular entries so far. Of course there are thousands of projects on Hackaday.io that aren’t entered into the Hackaday Prize this year, and if you’re behind one of those, this is your call to step up.

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Introducing the Raspberry Pi 3

TL;DR: The Raspberry Pi 3 Model B is out now. This latest model includes 802.11n WiFi, Bluetooth 4.0, and a quad-core 64-bit ARM Cortex A53 running at 1.2 GHz. It’s a usable desktop computer. Available now at the usual Pi retailers for $35.

News of the latest Raspberry Pi swept around the Internet like wildfire this last weekend, thanks to a published FCC docs showing a Pi with on-board WiFi and Bluetooth. While we thank the dozens of Hackaday readers that wrote in to tell us about the leaked FCC documents, our lips have been sealed until now. We’ve been doing a few hands-on tests with the Pi 3 for about two weeks now, and the reality of the Pi 3 is much cooler than a few leaked FCC docs will tell you.

The Raspberry Pi 3 Model B features a quad-core 64-bit ARM Cortex A53 clocked at 1.2 GHz. This puts the Pi 3 roughly 50% faster than the Pi 2. Compared to the Pi 2, the RAM remains the same – 1GB of LPDDR2-900 SDRAM, and the graphics capabilities, provided by the VideoCore IV GPU, are the same as they ever were. As the leaked FCC docs will tell you, the Pi 3 now includes on-board 802.11n WiFi and Bluetooth 4.0. WiFi, wireless keyboards, and wireless mice now work out of the box.

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Raspberry Pi Zero – Turning the Pi into a USB Gadget, over USB

[gbaman] has figured out a simpler way to program the new Raspberry Pi Zero over USB without modifying the board. Why is this useful? One example which appealed to us was setting the Zero’s USB port up as a mass storage device. Imagine plugging in your Pi powered robot, dragging and dropping a Python script into the mass storage device that shows up, and pressing a button on the robot to run the new script. Pretty fancy for $5.00.

You can get the PI to emulate a whole range of devices from a USB MIDI controller to a simple USB serial interface. We’re excited to see what uses people come up with. Unfortunately the Pi Zero is still out of stock most everywhere as we wait for the next production run to finish. Though if you’ve got one, why not check out a few of our thoughts and experiences with the device!

[gbaman] based his work off the work done by [Dave-0] and others over at the Raspberry Pi forums. [LadyAda] also has a version of this hack, which we covered, that involves soldering a header to the pi and using a UART adapter.

[via Hacker News]

Yet Another Pi Zero USB Hub

The Raspberry Pi Zero was back in stock at Adafruit this week – for about eight minutes. That means a few more people get Pi Zeros, many more will put them up on eBay, and everyone is working on their own version of a Pi Zero USB hub. The latest version of a Pi Zero hub comes from [Nate], and he’s doing this one right. His Pi USB adapter adds four USB ports and features not found in other DIY USB hubs like fuses and ESD protection.

As with other Pi Zero USB hub add-ons, this build relies on a USB hub controller, a few passives, and not much else. The chip used in this hub is the FE1.1s chip, a highly integrated 4-port hub controller that can be found through the usual Chinese resellers. This hub controller doesn’t require much, just a 12MHz crystal, a few passives, and four USB jacks.

Of particular interest is how [Nate] is connecting this hub to the Pi Zero. He’s left the option open for using either a USB cable, or soldering the USB’s differential pairs directly between the Pi and the hub. In either case, the hub should work, and with the addition of the zeners, fuses, and other parts that keep the hub from frying itself, [Nate] might have a very nice project on his hands.

Turning The Pi Zero Into A USB Gadget

The Raspberry Pi Zero is limited, or so everyone says, and everyone is trying to cram a USB hub and WiFi adapter on this tiny, tiny board. One thing a lot of people haven’t realized is that the Raspberry Pi Zero comes with a USB OTG port, meaning it can function as a USB device rather than a USB host. This means the Raspi can become a serial device with just a USB cable, an Ethernet device, MIDI device, camera, or just about anything else you can plug into a USB port. Adafruit has your back with a tutorial for using the USB OTG port as a serial and Ethernet interface, and the possible applications are extremely interesting.

The only requirement for using the USB OTG port for device applications is an update to the kernel. This is easily installed by dumping a few files on an SD card and a employing bit of command line wizardry. The simplest example is setting up the Pi Zero as a USB serial device, allowing anyone to log into a serial console on the Pi with just a USB cable.

A slightly more interesting application is setting up the Pi as an Ethernet gadget. This effectively tunnels all the networking on the Pi Zero through a USB cable and a separate computer. The instructions are extremely OS-specific, but the end result is the same: you can apt-get on a Pi Zero to your heart’s desire with a new kernel loaded onto the SD card and a USB cable.

This experimentation is just scratching the surface of what is possible with the OTG port on the Pi Zero. MIDI devices are easy, and with a ton of GPIOs, the Pi Zero itself could become a very interesting musical instrument. Want the Pi Zero to be a storage device? That’s easy too. The USB Gadget will end up being one of the most exciting uses for the Pi Zero, and we can’t wait to see what everyone will come up with next.

Turning a Pi Into a PDP

There’s no better way to learn how to program a computer than assembly, and there’s no better way to do assembly than with a bunch of blinkenlights and switches. Therefore, the best way to learn programming is with a PDP-11. It’s a shame these machines are locked up in museums and the garages of very cool people, but you can build your own PDP-11 with a Raspberry Pi and just a few extra components.

[jonatron] built his own simulated version of the PDP-11 with a lot of LEDs, a ton of switches, and a few 16-bit serial to parallel ICs. Of course the coolest part of any blinkenlight simulator are the front panel graphics, and here [jonatron] didn’t skimp. He put those switches and LEDs on a piece of laser cut acrylic with a handsome PDP11 decal. The software comes with a load of compiler warnings and doesn’t run anything except for very simple machine code programs. That’s really all you can do with a bunch of toggle switches and lights, though.

If this project looks familiar, your memory does not deceive you. The PiDP-8/I was an entry in this year’s Hackaday Prize and ended up being one of the top projects in the Best Product category. We ran into [Oscar], the creator of the PiDP-8, a few times this year. The most recent was at the Hackaday SuperConferece where he gave a talk. He’s currently working on a replica of the king of PDPs, the PDP-11/70.

Video below.

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