[Mr. Carlson] Fixes A Fridge

September 21, 2019 by Dan Maloney 28 Comments

A dead refrigerator is an occurrence determined to frustrate any homeowner. First there’s the discovery of hundreds of dollars in spoiled food, and then the cost of a repair call and the delay of the inevitable wait for parts. It’s clear to see why a hacker like [Mr. Carlson] would seek another way.

Now, normally a fridge repair video would by unlikely fodder for a Hackaday article. After all, there’s generally not much to a fridge, and even with the newer microprocessor-controlled units, diagnosis and repair are usually at the board-level. But [Mr. Carlson] has had this fridge since 2007, and he’s got some history with it. An earlier failure was caused by the incandescent interior lights welding relay contacts closed thanks to huge inrush currents when starting the cold filaments. That left the light on all the time, heating the interior. His fix was a custom solid-state relay using zero-crossing opto-isolators to turn the bulbs on or off only when the AC power was at a minimum.

That repair kept things going for years, but when the latest issue occurred, [Mr. Carlson] took a different tack. He assumed that a board that has been powered 24-7 for the last twelve years is likely to have a bad capacitor or two. He replaced all the caps, threw in a few new relays to be on the safe side, and powered the fridge back up. It whirred back to life, ready for another decade or so of service.

Kudos to [Mr. Carlson] for his great repair tips and his refusal to surrender. The same thing happened when his solder sucker started to give up the ghost and he fixed it by adding a variable-frequency drive.

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Minivac 601 Replica Gets A Custom Motorized Rotary Switch

July 13, 2019 by Dan Maloney 2 Comments

One of the joys of electronics as a hobby is how easy it is to get parts. Literally millions of parts are available from thousands of suppliers and hundreds of distributors, and everyone competes with each other to make it as easy as possible to put together an order from a BoM. If you need it, somebody probably has it.

But what do you do when you need a part that doesn’t exist anymore, and even when it did was only produced in small numbers? Easy – you create it yourself. That’s just what [Mike Gardi] did with this unique motorized rotary switch he needed to complete his replica of a 1960s computer trainer. We covered his build of the Minivac 601, a trainer from the early computer age that let experimenters learn the ropes of basic digital logic. It used mostly relays, lamps, and switches connected by jumpers, but it had one critical component – a rotary control that was used for input and, with the help of a motor, as an output indicator.

[Mike]’s version of the switch is as faithful to the original as possible, at least in terms of looks. The parts are mostly 3D-printed, with 16 reed switches embedded in the walls and magnets placed in the rotor. The motor to operate the rotor is a simple gear motor mounted to a hinged bracket; when the rotor needs to move, a solenoid pulls the motor’s friction drive wheel up against the rotor.

The unique control slots right into the Minivac replica and really completes the look and feel. Hats off to [Mike] for a delightful replica of a lost bit of computer history and the dedication to see it through to completion.

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A Faithful Replica Of An Early Computer Trainer

June 17, 2019 by Dan Maloney 11 Comments

Turn the clock back six decades or so and imagine you’re in the nascent computer business. You know your product has immense value, but only to a limited customer base with the means to afford such devices and the ability to understand them and put them to use. You know that the market will eventually saturate unless you can create a self-sustaining computer culture. But how does one accomplish such a thing in 1961?

Enter the Minivac 601. The brainchild of no less a computer luminary than Claude Shannon, the father of information theory, the Minivac 601 was ostensibly a toy in the vein of the “100-in-1” electronics kits that would appear later. It used electromechanical circuits to teach basic logic, and now [Mike Gardi] has created a replica of the original Minivac 601.

Both the original and the replica use relays as logic switches, which can be wired in various configurations through jumpers. [Mike]’s version is as faithful to the original as possible with modern parts, and gets an extra authenticity boost through the use of 3D-printed panels and a laser-cut wood frame to recreate the look of the original. Sadly, the unique motorized rotary switch, used for both input and output on the original, has yet to be fully implemented on the replica. But everything else is spot on, and the vintage look is great. Extra points to [Mike] for laboriously recreating the original programming terminals with solder lugs and brass eyelets.

We love seeing this retro replica, and appreciate the chance to reflect on the genius of its inventor. Our profile of Claude Shannon is a great place to start learning about his other contributions to computer science. We’ve also got a deeper dive into information theory for the curious.

Thanks to [Granz] for the tip.

Moped Turn Signals, Now With More Cowbell

June 7, 2019 by Dan Maloney 14 Comments

Cue up the [Christopher Walken] memes, it’s time for moped turn signals with more cowbell. Because moped turn signals with less cowbell are clearly the inferior among moped turn signals.

It seems that [Joel Creates] suffers from the same rhythm recognition disorder that we do. The slightest similarity between a rhythmic sound such as turn signals, and any song in our seemingly infinite intracranial playlist cues up that song for the rest of the day. [Joel] heard “(Don’t Fear) The Reaper” in his turn signals, and that naturally led to a need for More Cowbell. So with a car door lock actuator, a relay, an improvised clapper, and a lot of hot glue and cable ties, the front of his scooter is now adorned with a cowbell that’s synchronized to the turn signals. The video below shows that it’s of somewhat limited appeal in traffic, but at least [Joel’s dad] was tickled pink by it.

Kudos to [Joel] for marching to the beat of his own [Gene Frenkle] on this one. It may be a little weird, but not as weird as an Internet of Cowbells.

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Sniffing CAN To Add New Features To A Modern Car

May 9, 2019 by Tom Nardi 40 Comments

It used to be that there wasn’t a problem on the average car that couldn’t be solved with a nice set of wrenches, a case of beer, and a long weekend. But the modern automobile has more in common with a spaceship than those vintage rides of yesteryear. Bristling with sensors and electronics, we’re at the point that some high-end cars need to go back to the dealer for even minor repairs. It’s a dark time for the neighborhood grease monkey.

But for those of us who are more likely to spend their free time working with a compiler than a carburetor, a modern car can be an absolute wonderland. That’s what [TJ Bruno] found when he recently started experimenting with the CAN bus on his 2017 Chevy Cruze. Not only was he able to decode how the different switches and buttons on the dashboard communicated with the vehicle’s onboard systems, he was able to hack in a forward-looking camera that’s so well integrated you’d swear it was a factory option.

The idea started simple enough: using some relays, [TJ] planned on physically switching the video feed going to the Chevy’s dashboard between the stock rear camera and his aftermarket front camera. That’s all well and good, but the car would still only bring up the video feed when the gear selector was put in reverse; not exactly helpful when he’s trying to inch his way into a tight spot. He needed to find a way to bring up the video display when the car was moving forward.

With a PCAN-USB adapter connected to the car’s OBD-II port, he shifted into and out of reverse a few times and noted which messages got transmitted on the network. It wasn’t long before he isolated the proper message, and when he injected it with his laptop, the dashboard display switched over to the backup camera regardless of what gear the car was in. Building on this success, he eventually figured out how to read the status of all the buttons on the car’s dashboard, and programmed an Arduino to listen for the appropriate signals.

The final piece of the puzzle was combing bringing both of these capabilities, so that went the appropriate button was pressed on the dashboard the Arduino would not only send the signal to turn on the video display, but kick the relays over to switch the camera source. Now [TJ] has a front-facing camera that can be called up without having to kludge together some button or switch that would never match the modern styling of the vehicle’s interior.

A couple years back we saw a similar project to add a backup camera to a Peugeot 207 that was too old to have one from the factory, and more recently we saw how CAN hacking can allow you to fight back when your car’s touch screen interface robs you of simple pleasures like pushing buttons and turning knobs.

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Putting Some Smarts Into An Electric Car Charger

April 27, 2019 by Tom Nardi 22 Comments

Many electric cars feature a timer capability that allows the owner to set which hours they want the vehicle to start pulling a charge. This lets the thrifty EV owner take advantage of the fact that the cost of electricity generally goes down late at night when the demand is lower. The Renault Zoe that [Ryan Walmsley] owns has this feature, but not only does it cost him extra to have it enabled, it’s kind of a hassle to use. So being an enterprising hacker, he decided to implement his own timer in the charger itself.

Now controlling high voltages with a lowly microcontroller might sound dangerous, but it’s actually not nearly as tricky as you might think. The charger and the vehicle actually communicate with low-voltage signals to determine things like the charge rate, so it turns out you don’t need to cut into the AC side of things at all. You just need to intercept the control signals between the two devices and modify them accordingly.

Or do you? As [Ryan] eventually realized, he didn’t need to bother learning how the control signals actually worked since he wasn’t trying to do anything tricky like set the charge rate. He just wanted to be able to stop and start the charging according to what time it was. So all he had to do was put the control signal from his car through a relay controlled by a Particle Photon, allowing him to selectively block communication.

The charger also had an optional key lock, which essentially turns the controller off when the contacts are shorted. [Ryan] put a relay on that as well so he could be absolutely sure the charger cuts the juice at the appropriate time. Then it was just a matter of getting the schedule configured with IFTTT. He mentions the system could even be tweaked to automatically control the charger based on the instantaneous cost of electricity provided by the utility company, rather than assuming overnight is always the most economical.

We’ve seen a fair amount of electric car hacking, but with only a few exceptions, the projects always steer clear of modifying the actual chargers themselves. In general hackers feel a lot safer playing around in the world of DC, but as [Ryan] has shown, safely hacking your EV charger is possible if you do your homework.

Reverse Engineering A Telephonic Relay Device

March 23, 2019 by Lewin Day 20 Comments

The Plain Old Telephone Service, or POTS, doesn’t get a lot of love from the average person anymore. Perhaps once in a while a payphone will be of use when a phone battery has died, but by and large many people simply don’t have hardwired phones anymore. However, that doesn’t mean that the old landline can’t be put to good use. As [Felix Vollmer] shows us, it’s still possible to get useful hardware running over the phone line.

The YC-KZ02DN is a simple device which hooks up to a standard phone line. It’s capable of answering calls and responding to commands by switching its various relays on or off. [Felix] wasn’t quite happy with the stock functionality, however. Investigation showed the onboard STC15W202S microcontroller can be repogrammed over serial via an unpopulated header. Thus opened the door to hacking the device.

[Felix]’s alternative firmware has a couple of key features that make it valuable. Longer PINs are supported, decreasing the likelihood that malicious actors can gain access to the system. Additionally, the device is set to restore the last relay state after a power loss event. This makes the device far more useful for situations where it’s important to ensure consistent operation. It’s no use if an intermittent power loss stops your livestock’s water trough from filling, for example.

In this day and age of the Internet of Things, an old school telephony hack warms the cockles of our hearts. We’re suckers for anything that recalls the days of rotary dialing and speaking with the operator, after all.