Nixie Clock Uses Ingenious Software RTC

May 31, 2015 by 19 Comments

There’s something about Nixie Tube Clocks that keeps drawing hackers to build their own iterations, even if its been done a gazillion times before. Their depleting supply, and the high voltage drivers to control them, makes it all the more interesting. [Pete Mills], a veteran of several interesting projects, many of which we have featured here, is no exception and decided to build his own version of a Nixie Tube Clock, but with several nifty features.

To put it in a nut shell, his Clock uses Nixie tubes for display, has USB serial communication, temperature measurement, AC frequency measurement, time and date keeping with a software based RTC, software driven boost converter for the 175V DC nixie tube supply and a windows app for clock configuration.

The software based time keeping is pretty interesting. It is essentially a method to calibrate the crystal to more closely match real time, and some code to keep track of the time and date.  This obviously leads to a reduction in components and the spin-offs that comes with that; increased reliability, cost reduction, real estate savings. The RTC code can easily be ported to other clock projects irrespective of the display used. Besides keeping track of time and date, it can also account for leap years, and report the day of the week. A zero-crossing detector connected to the low-voltage transformer supply that powers the clock can also be used as an alternative way of keeping time.

When connected to a serial console over UART, the clock can report back many variables depending on the queries it receives. The high voltage DC needed to drive the Nixie tubes is generated using a simple boost converter controlled by the micro controller. An important “gotcha” that [Pete] deduced after blowing off several fuses, was to disconnect the micro controller port connected to the PWM timer and explicitly set it to output low via software. There’s a couple of other issues that he ran into – such as board layout, power supply, incorrect pullups – that make for interesting reading. The clock enclosure is still work in progress, but [Pete] hopes to get it done sometime soon.

He also wrote a Windows application – Nixie Clock Communicator – to help with time setting and calibration. Finally, he describes in detail the process of calibrating the clock’s software based RTC. Based on his calculations, the clock will drift by about 48 seconds over an 8 month period. Since he will be adjusting for DST much sooner than that, his clock ought to be off from correct time by not more than a minute at any given time. Not bad for a clock that does not use a dedicated RTC chip. [Pete] still has some of the prototype boards to give away if someone is interested. If you’d rather build it yourself from scratch, [Pete] has posted the software code, schematics and PCB, and a BoM.

Dual Pet Food Dispenser Is Doubly Convenient

May 31, 2015 by 21 Comments

Does your dog or cat wake you up every morning, demanding to be fed? Maybe you feed Sparky in the evenings instead. But doesn’t that limit your spontaneity? It sure limited [Jorge]’s after-work plans. He has two dogs that eat the same type of food, but in different quantities. This was a big factor in the design and execution of his dual pet food dispenser.

[Jorge] started by modeling his requirements in 3D. Dispensing takes place in two stages as food moves from the storage hopper to the bowls. A 12V printer motor turns the 3D-printed auger, which transports the nuggets to the staging area. Here, a servo controls a ramp in a see-saw motion, sending the food sliding sideways into one bowl or the other.

The dispenser is designed around a PIC18F2420. Although this micro was [Jorge] ‘s second choice, it ticks all the boxes in the design. His acrylic enclosure features four push buttons for navigation and selection through the 16×2 LCD. [Jorge] has an issue with the food getting stuck in the first stage. A friend suggested that he use vibration to agitate the food, but that didn’t work. [Jorge] ultimately added a stirring shaft with spokes that helps keep the morsels moving. Take the tour after the break.

If you want to dispense single doses of food on a timer, check out this automatic cat feeder made from scavenged parts.

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More GPIOs For The ESP8266

May 31, 2015 by 26 Comments

The ESP8266 is an incredible piece of hardware; it’s a WiFi module controllable over a serial port, it’s five freaking dollars, and if that’s not enough, there’s a microcontroller on board. Until there’s a new radio standard, this is the Internet Of Things module.

The most common version of the ESP, the -01 version, only has a 2×4 row of pins for serial, power, configuration, and two lines of GPIO. It’s a shame that module only has two GPIOs, but if you’re good enough with a soldering iron you can get a few more. It took a lot of careful soldering, but [Hugatry] managed to break out two more GPIOs on this tiny module.

According to [Hugatry] a lot of patience to solder those wires onto those tiny pads, but after finishing this little proof of concept he discovered a Russian hacker managed to tap into four extra GPIOs on the ESP8266-01 module (Google Translatrix).

As a proof of concept, it’s great, but there’s more than one ESP module out there. If you’re looking for a cheap WiFi module, check out the ESP-03, -04, or -07; they have nice castellated pins that are exceptionally easy to solder to.

Video below.
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From Scrap To Sword: Casting Pewter

May 31, 2015 by 17 Comments

[TheBackyardScientist] has been living up to his name, this time by casting a pewter sword in his yard. Pewter is a soft alloy of mostly (85–99%) tin along with copper, antimony and bismuth. Older pewter castings often used lead as well. The great thing about pewter is its low melting point of 170–230 °C. At such low temperatures, pewter can be melted down on a common hot plate. Think of it as an easy way to get into the world of metal casting – no forge required. Of course, anyone who has been splashed with solder will tell you that hot molten metal always deserves a lot of respect.

[BackyardScientist] obtained his metal by hunting the local thrift stores. He used the “lost foam” method of casting, by carving a sword out of styrofoam. The sword was embedded in a 5 gallon bucket of sand with a riser to allow the mold to be filled. The pewter was melted on a cheap hot plate, and poured into the mold. The hot metal melts the foam on contact, simultaneously filling up the cavity left over in the sand mold. [BackyardScientist] was left with a solid pewter sword. It won’t hold an edge, but it is a great illustration of the technique.

Click past the break to see [TheBackyardScientist’s] video.

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rotary cell phone

Rotary Phone Converted For Mobile Use

May 31, 2015 by 15 Comments

As a society we are moving away from land line phones while mobile devices are becoming more and more prevalent. It is not uncommon for people to only have a cell phone and completely skip out on the corded home phone. While this move may be for convenience, there is one difference between the two phone types that didn’t ring well with [Stavros]. He’s an angry phone talker and misses the ability to slam down a phone handset. Now [Stavros] could just have a corded home phone but he wanted a mobile option for handset slams so he came up with a project called iRotary. It’s an old school rotary phone converted to be battery powered and uses cell phone networks for making calls.

At the heart of the project is an Arduino. The Arduino is a great choice as it can easily decode the phone’s rotary dial pulses. The Arduino code takes all of the individual dialed numbers and combines them into a phone number. The sketch is set up so that after the 10th digit is read, the phone call is placed using an off the shelf GSM shield and associated library.

Since a battery would be necessary to make this phone mobile, one was installed inside the case along with a charging circuit. [Stavros] hasn’t done any long-term endurance studies but he has had the phone on for several hours at a time without any problems. So, now he can rest easy knowing that an angry hang-ups are never out of his reach, regardless of where he may be. And since he’s a nice guy, he’s made the source code available for anyone wanting to make something similar.

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Transparent Alarm Clock Runs Linux

May 30, 2015 by 24 Comments

[Benoit] was using an extremely old alarm clock which normally ran on mains power, and he plugged it in to his computer’s UPS to keep it operational during power outages. He noticed that when the UPS switched on that the clock would run fast, though, and apparently it was keeping time by watching the power system frequency. To solve this problem he created his own feature-dense clock which runs Linux.

This alarm clock has everything: seven-segment displays housed in clear epoxy, a touch interface, battery backup, the ability to retrieve the time from an NTP server, and a web interface to change the clock’s settings over the network. That was a large part of [Benoit]’s decision to have the clock run Linux; the network capabilities add a lot of functionality to the clock like the ability to send commands to other devices at particular times. The clock runs on an Aria G25 SOM and has a custom case that looks very professional.

We’re suckers for a high-quality clock builds here, and [Benoit]’s most recent project hits all of our buttons. Even though it doesn’t currently drive people insane or tell confusing time, the Linux and networking capabilities could certainly open up options!

bike wheel wind turbine

Juice-Spewing Wind Turbine Bootstrapped From Bike Parts

May 30, 2015 by 25 Comments

Wind Turbines are great, they let us humans harness the energy of the wind. Wind is free and that is good, but spending a ton of money on a wind turbine setup begins to make the idea less appealing. [Ted] has spent many years building low cost wind turbines and this one is not only simple but can be made from mostly found parts.

It’s easy to identify the main rotor hub and blade frame which are made from an old bicycle wheel. The blades are standard aluminum flashing normally used in home construction and are attached directly to the spokes of the bike wheel. Mounted below the bike rim is a permanent magnet motor that acts as a generator. A belt couples the motor to the main rotor and uses the tire-less rim as a pulley.

[Ted] has strapped this beast to the roof of his car to measure how it performs. At 12 mph, he’s getting between 18-20 volts at 2 amps. Not too bad! Bikes and bike parts are cheap (or free) and there is no surprise that they have been used in wind turbine projects before, like this one that hangs from a kite.