This one's still a work in progress, but I figure I'm far enough along now to post some information about it.
I love nixie tubes. I also have made a few timepieces in the past and have been looking for a good project to familiarize myself with the efm32 line of microcontrollers (I just started here at SiLabs a few months ago, and have been working solely with em35x silicon so far). So I decided that my desk needed an efm32 based nixie clock as a piece of office flair
The first step to this project was getting the electrics managed. Each of those tubes requires 180V DC to ignite the filament, which is slightly higher than the an efm32 can tolerate as input voltage. I designed a circuit board that uses an inductor, a 555 timer, and a feedback resistor to take in 9V drom a wall wart and 1) boost it to 180V for the tubes and 2) pass it through an LDO to power the micro controller. I added a 16 pin 100 mil header for each set of two tubes, which in turn goes to a duplex daughter board.
Each daughter board contains all the tube specific hardware for two IN-12A tubes (the idea being I can make a different daughter board for different types of tubes in the future without having to re-spin the main board).
Once I had my circuits made, it was time to write the software. I used a wonder gecko starter kit, because it is roughly the size of my booster board and has enough GPIOs that I didn't have to rely on an external shift register to handle the tube control (please forgive the choice in case here, it was the best I could do in 10 minutes with an x-acto knife : )
I eventually want to use a Blue Gecko for this project so I can add some fun controls over phone via BLE. Once I get the software for that good to go, I plan on spinning either a version of the boost board that has the gecko on board or one that is compatible with the 100 mil headers on the Gecko kits, which will obviate the need for all the messy wires.
Once I had all the software done and the tubes working, it was time to make a housing. My goal is to have the tubes mounted on side lit etched acrylic, with all of the circuitry visually exposed behind the tubes. First step here was to do a quick design using the Silicon Labs logo and the Gecko emblem. I'm still considering making some changes here, so if anyone reading this has graphic design experience and can provide feedback, I'd be very open to constructive criticism or assistance. Once the design was made, it was off to the laser cutter to etch the design and cut out the acrylic. I was pretty happy with the results.
On a side note, I can not use a laser cutter without marveling at what a huge feat of engineering achievement they are.
I was unfortunately very rushed when doing the acrylic design (I was running at the end of a borrowed half hour's time on the laser cutter), so mistakes were definitely made with respect to sizing and boundaries. It was still good enough to get the tubes to fit in the holes, though, which was the primary objective.
For the prototype, I decided to use red oak to hold the acrylic. I cut a channel a bit bigger than the acrylic and will eventually be gluing everything together. I'm very happy with the results so far, especially considering this is the first attempt at doing an enclosure of this type. My WS2812b LED strips arrived in the mail over the weekend, so hopefully I'll have the software to drive them done soon. I also have better acrylics and a t-slot router bit on the way in the mail, which will (hopefully) allow me to get a better mounting solution in place. I'll update this post as I make more progress, but feedback is certainly welcome at this stage
What project are you working on this summer? A low-power game module run by the EFM32 microcontroller? A touchless optical switch using the Si114x sensor? Or a Rube Goldberg machine connected via the EM357 ZigBee chip?
Whatever it is, share your cool project with your fellow engineers here by posting a photo of your project using a Silicon Labs' part and a short description of what it is in the comments below. We’ll pick three best photos based on most kudos (50%) and a voting system by our in-house judges (50%). The winners will receive a free PEAK™ (Matte Black / Black, $199.99).
In order to be eligible, your entry must meet the following requirements:
Your entry will be judged by three or more employees of Silicon Labs and will be judged based on
Number of winners: 3 (only one entry per user)
Prize: 1 x PEAK™ (Matte Black / Black, $199.99)
Contest period: 27 July, 2015 – 21 August, 2015
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What do you get when you combine a 32-bit MCU, old computer parts, CD-ROM, a hanger and a stack of QFN64 chips? The Gecko Blaster (or basically, a high-speed product launcher!)
Watch a quick video on how it works:
Halfdan and Maximilian
The idea for this project came from a canon-like device built with Lego blocks. The goal was to launch chips using a brushless DC motor (from an old CD-ROM) controlled by a Giant Gecko. EFM32 Giant Gecko chips in QFN64 packages were one of the package types used as ammunition. The sample code for build-easy motors used is available on Simplicity Studio.
Fig: Hack-a-Gecko Project – The Gecko Blaster
Fig: The Gecko Blaster in action
Fig: The Project Overview
This project was intended as a fun activity and just goes to show how much scope there is to experiment with the Giant Gecko chips. For instance, the Gecko Blaster can shoot the chips at a speed high enough to make holes in paper! Its utility and applications may be limited at this point but should act as encouragement to experiment in fun ways with the Giant Gecko – it may invariably lead to something fun as well as an innovative application.
Fig: Chips shot at a high speed made holes in paper
To find the documentation, go to simplicity studio, enter “EFM32GG990F1024” in the field under product. Press “Application Notes”, search for “AN0816 Brushless DC Motor Control” and click open.
To read more about the Giant Geckos click here.
Silicon Labs provided our University design team with two free C8051F850 BLDC motor driver kits in exchange for a write-up on our project. Our team won second prize at the Electro-mobility 2015 student competition organized by Continental Iași on 8th-9th May at their location in Iași. We were then invited to showcase our project at the Euroinvent 2015 exhibition.
The goal of the project was to come up with a design of an autonomous car that satisfied the requirements as stated in the Electro-Mobility Contest design specification document. Mainly, this implied the design of a car driven by brushless motors with the ability to drive unassisted along a specified track.
Team of students and a teaching assistant from the Faculty of Electronics, Telecommunications and Information Technology of the "Gh. Asachi" Technical University of Iași, Romania participating in the Electro-Mobility Contest 2015.
The Dual Autonomous Motor design represents a wireless controlled 4 wheel drive car. The car steers by speed difference between left and right motors. A PiCamera records the car's movement and based on that information using the openCV image processing library the car can enter autonomous mode and drive itself under certain conditions (described in the contest track specification document).
The design can be broken down into three main parts: software, hardware and mechanical.
Mechanical Implementation: A 4-wheel design was adopted due to stability issues of the 3 wheel design (2 front and 1 back). For better steering results an all-wheel drive solution had to be implemented.
Fig: Final mechanical implementation
Hardware Implementation: Industry proven solutions were preferred here, so the BLCD motors are controlled by two SiLabs C8051F850 BLDC motor driver kits. The drivers are connected to a Raspberry Pi 2 model B. Also connected to the Raspberry Pi is the PiCamera for track recognition in autonomous mode. Two Servo motors are used for adjusting the camera view angle. All the components are powered by a LiPo battery through dc-dc converters, except for the motor drivers which are connected directly.
Fig: System model of 3-Phase BLDC Motor drive
Software Implementation: Consists of three parts:
This design can also be used for other purposes. With minimal addition to the image processing algorithms, a color object tracker can be easily implemented. Due to the video streaming feature the design can be used for access and vision in unfriendly environments. With the addition of some sensors (temperature, pressure, chemical) it can be used for collecting data from a specific environment. The design easily allows the addition of several I2C sensors.
See attachment for detailed design description.