Programmable Logic II – CPL

June 25, 2014 by Bil Herd 66 Comments

There is a wide assortment of cheap development (dev) boards for Complex Programmable Logic Devices (CPLD), the smaller cousin of the Field Programmable Logic Array (FPLA)

Using an inexpensive board and the development software that’s free to download from the major programmable companies such as Xilinx and Altera, the only additional thing needed is a programmer module. Cheap ones are available on Ebay but I am hoping that someone takes the time to teach an ARM/Arduino to step in as a programmer.

I have a small collection of dev boards including some Ebay specials and also designs I did a few years ago to choose from. For today I am grabbing a newer board that has not been fully checked out yet; an Altera Max V device. I have stuffed the CPLD, the clock oscillator, some LED’s and part of the onboard power supply along with the JTAG header needed to program the CPLD and that’s about it.

Herdware CPLD 5M570ZT dedicated PCB with SRAM.

CPLD Schematic showing an Altera CPLD 5M570T144

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Fingerprint Scanner Both Simplifies And Complicates Opening Garage Door

June 25, 2014 by Rich Bremer 48 Comments

Fringer Print Scanner Garage Door Opener

Opening a garage door by hand is a lot of work and a hassle, hence the advent of the garage door opener. Nowadays, some people may even say just pushing the button of a remote control requires too much effort. [nodcah] is one of those people so he came up with a fingerprint scanner that controls a pre-installed garage door opener. All kidding aside, it is a cool project that lets you into your garaage, keeps unknown people out and doesn’t require you to remember to carry a key or remote.

In the center of this project is an ATmega328 that runs a custom Arduino code. This ATmega328 is responsible for controlling a 16 character, 2 line LCD screen as well as communicate with an off the shelf fingerprint scanner from Sparkfun. The fingerprint scanner has a built in CPU, can store up to 20 fingerprints and does all its own processing of fingerprint scans. It then communicates to the ATmega328 with simple commands over serial Tx and Rx lines.

The ATmega328, LCD and fingerprint scanner are all mounted outside the garage in a 3D printed enclosure. If the wires for the internal-garage open/close button were just run straight into this outdoor module, anyone could open it up, short the wires and get into the garage. To prevent this, if the ATmega328 gets the ‘OK’ from the fingerprint scanner, then it sends a signal to an ATtiny85 that is inside the garage. If the ATtiny85 receives the correct signal, it will then actuate the garage door opener by shorting the open/close button contacts. This prevents anyone from sneaking into the garage.

[nodcah] did a great service to the community by making all of the part list, schematics, instructions and Arduino code available so anyone can easily put this project together.

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Bluetooth Security And Capacitive Sensing Tool Cabinet Handles

June 25, 2014 by James Hobson 13 Comments

Locking tool cabinet

[Andy] needed a new set of locks for his tool cabinets at work, but not wanting to carry around another key (or to remember a combination!) he decided to throw this little hack together — solenoid locking, capacitive sensing, tool cabinet door handles.

To do this he’s using a Bluetooth low energy breakout board coupled with an Arduino, two solenoid locks, and two capacitive sensors. He’s modified a pre-existing iPhone app to control the system, dubbed: The BlueLock Control.

When [Andy] is present with his phone, the system can be activated, allowing for automatic unlocking the moment you touch the metal handle. Usually he leaves it unlocked for the majority of the work day, but as soon as the day is done it’s just a simple swipe on his phone to engage lock mode for the night. And just in case he’s also added manual push-buttons for both solenoids in case anything goes wrong with the capacitive sensors. Cool hack [Andy!]

While you’re at it, why not make a keyless entry system for your car using Bluetooth too?

Electric Chainsaw Teardown

June 24, 2014 by Eric Evenchick 67 Comments

An electric chainsaw with its case removed

For his Beyond Unboxing series, [Charles] tore apart a Ryobi cordless chainsaw to get a better look at how this battery powered tool works.

Inside he found a three-phase motor and controller. This motor looks like it could be useful in other projects since it has a standard shaft. The battery pack was popped open to reveal a set of LG Chem 21865 cells, and some management hardware.

With all the parts liberated from the original enclosure, [Charles] set up the motor, controller, and battery on the bench. With a scope connected, some characterization of the motor could be done. A load was applied by grabbing the spinning shaft with welding gloves. [Charles] admits that this isn’t the safest way to test a motor.

While it is a very fast motor, the cut-in speed was found to be rather low. That means it can’t start a vehicle from a stop, but could be useful on e-bikes or scooters which are push started.

This chainsaw a $200 motor, controller, and battery set that could be the basis of a DIY scooter. It sounds great too, as the video after the break demonstrates.

[Thanks to Dane for the tip!]

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Rooting The Nest Thermostat

June 24, 2014 by Brian Benchoff 57 Comments

nest-300x293 A few months ago, Google bought a $3.2 billion dollar thermostat in the hopes it would pave the way for smart devices in every home. The Nest thermostat itself is actually pretty cool – it’s running Linux with a reasonably capable CPU, and adds WiFi to the mix for some potentially cool applications. It can also be rooted in under a minute,

As [cj] explains, the CPU inside the Nest has a Device Firmware Update mode that’s normally used for testing inside the Nest factory. This DFU mode can also be used to modify the device without any restrictions at all.

With a simple shell script, [cj] plugs the Nest into his laptop’s USB port, puts the device into DFU mode, and uploads a two-stage booloader to enable complete control over the Linux-powered thermostat.

As a bonus, the shell script also installs an SSH server and enables a reverse SSH connection to get around most firewalls. This allows anyone to remotely control the Nest thermostat, a wonderful addition to the Nest that doesn’t rely on iPhone apps or a cloud service to remotely control your Internet enabled thermostat.

Video of the rooting process below.

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Drones And Robots Come Out To Play At Sparkfun’s 6th Annual Autonomous Vehicle Competition

June 24, 2014 by Adam Fabio 9 Comments

Sparkfun AVC 2014

Sparkfun Electronics held their 6th annual Autonomous Vehicle Competition last weekend, and this year was bigger than ever before. The action was at Boulder Reservoir in Colorado, but anyone could follow along (with a few technical difficulties) on the YouTube LiveStream. (Part 1), and (Part 2).

The story of the day was Team SHARC’s Troubled Child, which won the ground vehicle doping class. Rather than mess around with miniature cars, Team SHARC built their ‘bot out of a freaking Jeep, a 1986 Jeep Grand Wagoneer to be exact. Troubled Child had no problem getting around the course. One could say it carried the entire team. Literally – the rest of Team SHARC’s robots are riding along on top of Troubled Child in the picture up there.

There was also plenty of action in the aerial competition. Sir Crash-a-Lot was the first drone to find a watery doom at Boulder Reservoir. The last we saw of it on the stream, the team was looking for some divers.

Aircraft can not be hand launched at the AVC. Not a problem for rotary-winged vehicles, but this rule has led to some interesting solutions for fixed wing aircraft. The disguised “Team Falcon” showed up with an incredible compressed air launcher, which used a gallon water jug to fire their delta-winged plane to a clean run. Team Karma550 wasn’t quite as lucky, with their helicopter crashing hard, and throwing up quite a bit of smoke.

We’re still waiting for more detailed results, but if you want the full scores, they are available on Sparkfun’s AVC scoreboard page.

Programmable Logic I – PLA/PAL

June 24, 2014 by Bil Herd 25 Comments

Yeah I am still a little pissed that the competition is still around and we aren’t, and by “we” I mean Commodore Business Machines (CBM). It was Commodore that had the most popular home computer ever in the C64 (27 Million) and it was a team of MOS engineers after all, that had the idea to make a “micro” processor out of a 12 square inch PCB.

MOS Technology in King of Prussia/Norristown

Of course they did work at Motorola at the time and “Mot” did not want anything to do with a reduction of the profit margin on the pie-plate size processor. Of course MOS got sued by Motorola but that was an average Tuesday at MOS/CBM. I absolutely credit CBM with buying the MOS Technologies chip foundry, as together we could make our own processors, graphics chips, sound chips, memory controllers, and programmable logic.

With this arsenal at our call we didn’t have to make compromises the way other companies did such as conforming to the bus spec of an industrial standard 6845 or having to add extra logic when a custom extra pin would work. We could also make sprites.

6502 Design Team (EE Times 1975, archive.archaeology.org)

The compromise we did have to make when designing was cost, and I mean the kind of cost reduction where finding a way to save a dollar ($1USD) saved millions in the production run. I knocked $.90USD out of a transformer one day and I couldn’t focus the rest of the day due to elation.

Cost reduction is a harsh mistress however as you can’t just do it a little some of the time or only when you want to. The mental exercise of multiplying anything times a million was always there, it made it hard to buy lunch — I’d be blocking the lunch line while figuring the cost of a million tuna sandwiches FOB Tokyo Continue reading “Programmable Logic I – PLA/PAL” →