What is “Ask an engineer”? From the electronics enthusiast to the professional community – “Ask an Engineer” has a little bit of everything for everyone. If you’re a beginner, or a seasoned engineer – stop in and see what we’re up to! We have demos of projects and products we’re working on, we answer your engineering and electronics questions and we have a trivia question + give away each week. Previous chats can be viewed at http://www.adafruit.com/ask
And don’t forget, 30 minutes before the show we’re doing our weekly show-and-tell. If you are on Google+ and want to join, just add/follow +Adafruit’s page and post a comment so you can be added to the show and tell circle. At 9:30pm ET you will see a link to the hang out. Just keep your mics muted until we call on you and have your project ready.
For those who just want to watch, you’ll be able to watch it live on Ustream here and we usually have a recorded version posted later.
In the United States, Flag Day is celebrated on June 14. It commemorates the adoption of the flag of the United States, which happened on that day in 1777 by resolution of the Second Continental Congress. The United States Army also celebrates the Army Birthday on this date; Congress adopted “the American continental army” after reaching a consensus position in the Committee of the Whole on June 14, 1775.
Happy Flag Day! June 14th is an American holiday that celebrates its flag. Usually, this isn’t a major holiday, but I thought it’d be interesting to make a flag for Flag Day. I remembered there was something called the Cicada Design Principle, that I wanted to try, and I thought I’d apply it to making non-repeating waves to a flag.
The Cicada Design Principle is a way to make seamless non-repeating backgrounds (for all intents and purposes) with just a few parts and some prime numbers.
NEW PRODUCT – Inductive Charging Set – 5V @ 500mA max. Inductive charging is a way of powering a device without a direct wire connection. Most people have seen inductive charging in a rechargable electric toothbrush: you may have noticed that you recharge it by placing it into the holder, but there’s no direct plug. These chargers work by taking a power transformer and splitting it in half, an AC waveform is generated into one, and couples into the second coil.
This is a basic charger set, and it does work, providing 5V DC output from the output half when the input half is powered with 9V to 12VDC. You can draw as much as ~500mA if the coils are 2 or 3 mm apart. If you only need 100 or 200mA you can be up 7mm apart. For 10mA draw, the coils can be up to half an inch (12.5mm) apart. Any non-ferrous/non-conductive material (eg air, wood, leather, plastic, paper, glass) can be used between the two coils. The material doesn’t affect the distance or efficiency. The coils do need to be fairly co-axial, try to get them to be parallel and have the circles line up for best power-transfer. (This is why the electric toothbrush must fit into the plastic holder, it’s lining up the two coils for best efficiency)
Because its an air-core transformer, it’s fairly inefficient. Only about 40% of the energy in shows up on the other end, but for low power or charging project. If you draw 5V 100mA on the output side (0.5W), you’ll need 0.5W * 2.5 / 9V = ~150mA from the input end. The quiescent current is about 70mA at all time, even when the other coil is not anywhere near by.
These are basic modules, probably used for some low cost toy. We don’t have any datasheets or specifications for them. We do see a feedback resistor divider on the output side using 0603 SMT resistors so an advanced user could solder in different values to turn it into a 3.3V output.
While I’m less and less allergic to float where performance is concerned, it does and always will have a significant precision problem since float is inherently ‘lossy’. When precision and performance matter with decimal values, there’s still no substitute for fixed point math. Using Fixed-Point Math for Embedded Applications by Steve Hageman has a lot of excellent advice on getting the most out of your MCU for the least amount of work, and contains some generally excellent tips for signal capture and manipulation.
NEW PRODUCT – FLORA Budget Pack. Get started with the fabulous Adafruit Flora platform with this lovely budget kit, just enough to get you started with this fun wearable computer. Included are enough parts to make your first wearable electronic project. There’s a Flora motherboard, four ultra-bright chainable RGB pixels, a 3xAAA battery holder and batteries, a battery extension cable, our high quality stainless steel thread, alligator clips to help you test out your parts and connections and a USB cable for reprogramming the Flora. Over $55 worth of goodies, for under $45.
These are just 2 of our distributors in the Asia region, make sure to visit the Adafruit distributor page to view all! We will be spotlighting Adafruit resellers from around the world on a regular basis!
We recently updated our distributor, reseller and hackerspace pricing! Now, 1 quantity has UP TO a 30% discount off many items, this is allows you to get a great discount by just ordering 1 of something. Great for folks who just want to try 1 item of each of something out in their store, etc. As always, once you order 50+ or more of something the discount goes UP TO 40% off many items as well. Note! *Not ALL items have reseller pricing, reseller pricing is for items we can discount for our resellers. We are adding more all the time! Remember, the minimum order is $250 per order, not including shipping.
We have a very easy reseller program and would love to have more great people & companies as a distributors/resellers/hackerspaces. Our products are high-quality and we think they’re the best engineered & designed in the market. How can you be a distributor? Just fill our form here, keep in mind the following questions!
Are you an online store, a physical store or a hackerspace that would like to distribute our products? Please include a link.
Can you place orders $250 and over (Not including shipping) each time?
Can you pay via paypal or credit card? For international large orders, can you pay via wire transfer?
Do you have a UPS account? (This is not required, but helpful).
We’ll be adding more features for resellers in 2013 enjoy! To become a distributor, click here.
Raspberry Pi E-mail Notifier Using LEDs Prepare Python: Raspberry Pi’s popularity make things so easy that it is almost scary. I set forth on a simple starter project of having the raspberry pi show me when new gmail messages arrive. After some searching it seems that lots of people are already talking about how to do this and there are some great examples. Michael over at MitchTech had the most ready to go code which I pilfered from. Adafruits Cobbler Breakout Kit makes the bread board experience even easier with the clearly labeled pins for each of raspi’s GPIOs. (read more)
Adafruit 16×2 Character LCD + Keypad for Raspberry Pi: This new Adafruit Pi Plate makes it easy to use an RGB 16×2 Character LCD. We really like the RGB Character LCDs we stock in the shop. Unfortunately, these LCDs do require quite a few digital pins, 6 to control the LCD and then another 3 to control the RGB backlight for a total of 9 pins. With this in mind, we wanted to make it easier for people to get these LCD into their projects so we devised a Pi plate that lets you control a 16×2 Character LCD, up to 3 backlight pins AND 5 keypad pins using only the two I2C pins on the R-Pi! (read more)
Good news to the OpenSprinkler Pi users: the same interval program firmware that runs on the latest OpenSprinkler has now been ported to OpenSprinkler Pi! This is due entirely to the generous contributions by Dan Kimberling, who ported the OpenSprinkler’s Arduino code to Python. The code is available for download at:
NEW PRODUCT PACK – Onion Pi Pack – Make a Raspberry Pi Tor Proxy. Feel like someone is snooping on you? Browse anonymously anywhere you go with the Onion Pi Tor proxy. Using this pack of parts and a free weekend you can build a project that uses a Raspberry Pi, a USB WiFi adapter and Ethernet cable to create a small, low-power and portable privacy Pi.
After it’s built, using it is easy-as-pie. First, plug the Ethernet cable into any Internet provider in your home, work, hotel or conference/event. Next, power up the Pi with the micro USB cable to your laptop or to the wall adapter. The Pi will boot up and create a new secure wireless access point called Onion Pi. Connecting to that access point will automatically route any web browsing from your computer through the anonymizing Tor network.