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Building your own custom Teensy

Phillip Schuster 27 Comments

UPDATE (November 24, 2016):

While this blog post still is very popular, it’s a bit old now. It still uses the old Teensy bootloader chip that is meanwhile deprecated and is not available anymore in larger quantities. However, I have been part of the dev team of the new Printrbot Simple 2016 and I have developed the display component which also uses the Teensy. Printrbot made everything open source.

If you are interested in building your own Teensy hardware, have a look in my Behind the scenes report and the Hardware explained report which makes the schematics and PCB available for download. This new PCB features the latest Teensy bootloader chip.

Although the bootloader chip is old that is described here, everything else like routing USB traces is not! Have fun reading it and let me know what you think!

UPDATE (December 15, 2015):

As you are reading this you might be interested in my custom built Teensy project named Little Helper. I made it Open Source under the MIT license including Schematics, Layout, BOM, 3D models of enclosing, and the complete Source Code. Have a look: Appfruits LittleHelper.

UPDATE (June 26, 2015):

Due to popular demand I have created a “reference board layout” and the schematics in EAGLE CAD (7.2) format. I created it by removing all components that were specific to my project. I just left in the Teensy part, the USB-port and a 3.3V regulator and rearranged the components so they fit in a small footprint. I have never produced the board but it should work (also it doesn’t do anything useful) as the components and layout have been working flawlessly in my own application.

This should speed up your development time for your own project. The board layout contains a switching regulator for the 3.3V which might be overkill if you are running your board of an USB-port as the provided regulator is mainly used with LIPO battery based projects and is hard to hand solder (I use a reflow oven which works quite well with QFNs). Use a simple LDO if you are just running your board with USB power. I have left the board layout for the switching regulator as it has been quite hard to get a good board layout with nearly no noise (switching regulators tend to be very noisy due to it’s nature) and should get you up and running quickly if you intent to do a LIPO-based project (of course you will need to add a LIPO charging circuit which can be found for example in Sparkfuns Power Cell product (see board and schematics for details).

All parts have an attribute named MPN for Manufacturer Part Number and MF for manufacturer. This way you can just use EAGLEs BOM-ULP script to export a BOM that you can directly upload to Mouser of DigiKey to get your parts.

Please note: Don’t order the MINI54TAN at DigiKey or Mouser. You will need to order the MINI54TAN at PJRC.com as this IC contains the core Teensy functionality!

You can find the EAGLE board layout and schematics in our Github repository: Custom Teensy 3.1 board layout and schematics. Please make sure to read this blog post before using parts or the whole “reference board” in your own project as there are quite a few things to consider which is largely documented and described below.

If you are reading my blog you might know that I really love Teensy. Teensy is an ARM powered very little Arduino compatible development board. It does one thing so damn good and I think that is very important for a development board and one of the keys to the success of Arduino: Easy programming. You do not need to connect wires and fancy boxes (JTAG programmers), just connect with USB and click on the program button.

But I am not a big fan of using development boards within final products. Although Teensy is really small it’s too high to pack two PCBs together. Using headers for easier soldering and it gets worse. If you really want to build small products you will often have to build your own PCB. Paul Stoffregen, the creator of Teensy enables these efforts by providing the bootloader MCU in his own store. They are very professionell. I had a few issues with german customs and they immediately sent out new ones and I received a refund for the first package that did not make it through.

Of course it’s not Pauls business model to help you out building your own Teensy, although he was very helpful in the forum. You will have to rely on the great Teensy community or blog posts like this one.

As I had a bit of trouble to get my custom Teensy board up and running I will try to give you some advice on how to build your own. (more…)

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Custom LCD Controller for Printrbot Simple (Metal)

Phillip Schuster 19 Comments

In order to print with the Printrbot Simple Metal you have to connect your computer with your printer via USB and make sure that the computer continuously sends data to the printer. If your computer crashes, your printer stops and your maybe long hour print is a piece of chunk. If your computer goes into stand by the result is the same. And there are various other reasons like energy consumption. The way to go is untethered printing.

The Printrbot Simple Metal is capable of that in two ways, both of them require a Mini-SD card inserted into the printer. The first way is to write the G-Codes generated by your Slicer, typically Repetier Host and Slicr to the SD-Card. Name it auto0.gcode, insert the card into the printer. Shut it down and on again. The printer should now start to print. But you will not know if it works for a couple of minutes as it’s first heating up. Nothing moves, etc. I tried that a couple of times and found the procedure to be very annoying.

The second method is using the Addon LCD Controller sold by Printrbot.

Getting your hands on a LCD Controller

Your Printrbot is already capable of displaying a nice LCD-Menu with all kinds of options and the option to browse the SD-card and run any print from it untethered from your PC. All that is needed is a Standard 20×4 LCD Display and a rotary encoder. A rotary encoder is a special kind of input sensor that sends signals when it is rotated.

Printrbot sells these LCDs for $65 in their store. But they still have that wood look. It does not match the Metals Design. And, as I am living in Germany you will have to wait a few days for it to arrive and you will likely have some issues regarding customs. I did not found a german distributor a few weeks ago so I wanted to built my own. A few days ago I have found 3ddinge.de selling the LCD Controller in Germany for €70. That’s a lot of money and by doing it yourself you will end up with 30-40 Euros for the LCD Controller.

(more…)

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