Sunday, March 31, 2013

LED Matrix Link: Last day of fundraiser

Today is the last day to get in on the LED Matrix Link. You can get yours on Tindie:

If you are unable to get one today, they will be in stock in about 2-3 weeks. After the fundraiser you can sign  up to be notified on the Tindie product page.

Tuesday, March 19, 2013

MAX7219 and eBay fakes

I have been receiving feedback that I can use eBay suppliers to lower my price on the MAX7219. I had previously considered that option, but after some research I have found that a lot of people are receiving counterfeits on eBay. While some counterfeits may work, their reliability is questionable and that would make my product unreliable. I do not believe that it is “good business” to support businesses and companies which pirate technology and sell it as if it were legitimate. I sincerely hope everyone understands why I am skeptical about using an unknown supplier for parts. Here is a good forum post about coming across the fake variety: The more units I can sell initially will increase my per-part discount, which allow me to lower my selling price.

For example if you look at the picture above, the line across the top is inline with pin 2. f you do a search on eBay or even Goole image search you can see that they lines up with pin 3. Also mine has a notch and the eBay ones all have a dimple. Not to mention there is no way someone can go to Maxim and get a price much lower then their lowest price they have.

LED Matrix Link on Tindie

The LED Matrix Link is now on Tindie. You can find it here:

Sunday, March 17, 2013

LED Matrix Link: Prototype

Update: I have listed the LED Matrix Link on Tindie as a fundraiser to get this started. You can support it here:

This prototype stems from another project\product to be that I haven't posted about except for this sneak peak: Project Sneak Peak. I noticed that most LED Matrix drivers on the market use shift registers to give a microcontroller the ability to control more LEDs than would be possible. Last year I came across the MAX7219 from Maxim Integrated. This cool little IC does all the work for you to drive a LED Matrix or LED Segment display. It uses a variation of the SPI protocol and can be daisy chained.  The other cool feature is you only need 1 resistor to set the max current and therefore the brightness. The best part is there is an Arduino library already.

MAX7219 LED Driver from Maxim Integrated

Sunday, March 10, 2013

USB Tester and Sick of Beige

From the beginning I designed the USB Tester to use the Dangerous Prototype Sick of Beige (SOB) standard PCB sizes. 50x31mm being the smallest rectangle and most ideal for the USB Tester. One of these reasons was that in doing so it would fit their standard acrylic cases which can be found at for $3. After waiting many days, my order has come in and I can show you one way you can use the case.

When you order the enclosure it comes with the following:
  • 4x Long Screws
  • 4x Short Screws
  • 4x Tall Stand offs
  • 4x Short Stand offs
  • 2x 50x31mm Acrylic cut with mounting holes

I found what worked is to use one acrylic sheet, all eight hex stand offs and the four long screws.

Needed parts