Oben_Komplett

Little Helper

If you have read one of my previous blog posts about building a custom Teensy you already know I have been working on a device based on the Teensy design.

Working in my lab with electronics I came across different little challenges once in a while, and noticed that I am missing tools to handle them efficiently. Just a quick list, I am sure you could add various items to the list:

  • What is the I2C address of a chip? (yeah, you can work through the Datasheet but the Datasheets I know don’t have an outline topic for this. It’s somewhere hidden deep in text somewhere)
  • What is the voltage range of the analog sensor in my current environment (take a photo sensor)?
  • Generating PWM or DAC signals
  • Does this circuit do anything?
  • Does this circuit do anything specific?
  • Reading serial output of your Microcontroller/Arduino project

Of course these aren’t any issues that you could not handle with the tools you have. But each of these take time. Checking an IC for it’s I2C address is easy: Connect it to your Arduino Uno, firing up the I2C Scanner sketch and you are good to go. That is 10 minutes minimum finding your Uno, wiring it up, firing Arduino IDE, uploading the sketch. And everything while your workspace is full of components, wires and stuff for the actual project you are working on.

I had been working on wireless sensors for a while that should take the least amount of power possible. You cannot add status LEDs as they draw way too much power. I had those PCBs lying around and had no clue if they do anything. I had to carry my laptop around, connecting it to the PCB to read the serial port to see what it does.

Why, the heck did I learn all that programming and electronics stuff and not using it to solve that issue. I thought of a small, portable device featuring some ports to connect stuff like sensors and other circuits and some menu driven user interface to trigger various modules doing tests, reading data, you get it.

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copper

Announcing Copper Beta

It all started with quite a complex PCB that I have been developing with Eagle CAD. A 4-Layer PCB with a lot of parts (>100) and quite a few ICs with a lot of pins. All these traces, all this pins and pads. There are so many possibilities to screw it up, that I always thought about this sentence all of you interested in this kind of stuff know well: “Hardware is hard”. It is.

And after triple checking every pin and trace, working through dozens of data sheets and controlling pin layouts I had it in front of me: My very own awesome PCB and hundreds of parts lying in front of me. I have a reflow oven and had to place parts on the board, prepared with solder paste. As you perhaps know, solder paste dries out after some time, so I had to be quick. I knew, that I had to place the 0.1uF capacitor on C1,C2,C3,C5,C6,… Searching for these parts on the boards silk screen drove me crazy. I had printed out assembly plans, etc. I had my MacBook running Eagle and started to search for each Part to get it selected in the board to know where to place it.

In these hours the idea of Copper took shape. At first, I only wanted a software that renders a simple representation of the PCB with a parts list. Select one or multiple parts and they are highlighted on the board. I fired up Xcode and a few days later I had it up and running. And it worked great. Whenever I discovered issues and shortcomings in Eagle CAD or my workflows and didn’t find a solution I added my own solution to “EagleCAD Viewer” (that’s been the name for quite some time).

Although I just did write this application for my own use, I invested quite some time to get rendering right, make the App look great and ironed out any bug I could find. Why? Because I just hate buggy, bad looking software, especially when it’s my own software.

A few months ago I decided to commercialize my Application and named it Copper. I think you will love it, and I really hope it will make your life easier. But before I sell this Application I must be sure it works great on all Mac OS X versions and with your PCBs. I don’t want you to buy into a beta test.

Update: Copper is available now for purchase (24,99 USD/Euro). There also is a free, fully functional Trial for Mac OS X 10.10+ available.

More Info and the Trial is available at our Copper product page.

Please report any questions to: support@copper-app.com.

Smarthub_Rev_1.8

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Little Helper working for the first time

Building your own custom Teensy

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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Rigol DS1074Z

Do I need an Oscilloscope?

If you are interested in Electronics, you will likely ask yourself sooner or later if you need an oscilloscope and especially what to buy if you have decided to do so. As I have been in the same situation a few months ago I likely know what’s going on in your head. Give me a minute to save you a few more sleepless nights thinking about this topic.

You can find a lot of infos about scopes. You will find hundreds of hours of video reviews of scopes, just look at the amazing EEVBlog. But non if these videos really gave me an answer to my question: Do I actually need a scope and what can I do with it.

Did you love playing with your dads HIFI-system and turning the knobs? Well, I know a scope is kind of a sexy tool with it’s knobs for you… But do you really need one? (more…)

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Compiling Qt 4.8.5 for Arietta G25

Arietta G25

On my way building an automated wireless home automation system I have been finally been drawn to Embedded Linux. It just makes sense. Driving Internet of Things devices based on Arduino or other directly programmed MCUs is not very efficient. You will have so much work with just building up a network stack for example based around a CC3000 (Available as a nice breakout board from Adafruit). And you will just redevelop what is available for linux for decades. But: Embedded Linux is a beast of a monster. It’s just a whole different universe.

There are so many devices to choose from, the most prominent example being the Raspberry Pi of course. But I wanted a solution that I can use for a final product. For my work I need a very small device and I don’t need all these connectors (Ethernet, HDMI, etc) so I have been searching the large catalog of SoMs (System on Module) and found “Arietta G25” by Acmesystems. I really love this little device and Acmesystems provides a lot of tutorials and help documents to get started quickly.

Find more infos about their great product line-up here: acmesystems.it.

After I had attached a 3.5 TFT (acmesystems has a well written tutorial on how to do that) I wanted to use it for a great User Interface. As you don’t want to build your own UI-System you will most likely find Qt. Qt is more than just a UI frameworks. It’s awesome as it features more or less the same as the whole Apple iOS system. It features it’s own (great) IDE, Interface-Builder for doing design work the WYSIWYG way and features an almost complete Framework with hundreds of C++ classes for all kinds of stuff. They even have a well written network stack helping a lot in doing IoT stuff.

But: Getting Qt to run on an embedded linux device is not that easy. It’s hard work. Requires hours of hours of your time building stuff. Of course there are systems like Yocto and Buildroot – I just got started with them and so far I don’t see it’s easier. As acme systems provides a few images to get started, I wanted Qt installed based on the acme systems solution.

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Teensy 3.1 PCB

Teensy – Arduino on Steroids

I love the Arduino Eco-System. Although I do not really like the IDE, the whole system is awesome. And it allows to quickly prototype ideas. And, as everything is Open Hardware, it also allows you to build your own PCBs with the same components used by Arduino. I am not in the business for creating a large-scale electronics product. But it’s very important for me that I could.

While working on my DIY Home Automation System I noticed some limitations with the current Arduino Hardware Offers. I have created my own Atmel 328p based PCB for my sensor nodes. The Atmel 328p is the MCU that drives Arduino Uno, Nano, Micro Pro, Sparkfuns Redboard and various other Prototype Systems. This MCU is quite fast (up to 20 MHz), can be run on batteries for a long time (if you care about your current consumption) and is easy to use program with the Arduino IDE. But there are limitations. You only get about 2K SRAM and 32K of program memory. That is enough for devices that only connect to a few sensors, driving a few motors, etc. But it’s not enough for more complex projects.

My DIY Home Automation Network needs a hub, that acts as a bridge between the Internet and the sensor nodes. Sensor Nodes are using nRF24L01+ Radio Modules. The Hub also hosts such a radio module, but has to send the signals in to the cloud. Although I wanted to have nice devices in the end I tried an Arduino Yun as a hub. The hub does not have to be very pretty as it will be placed in a small room that is not exposed. A small enclosure will do it. Arduino Yun is a great device that hosts both an Arduino MCU and a full-fledged Linux on the same device, connected with a bridge. Using the bridge you can run shell commands from the Arduino MCU on the Linux side and receive the results. You do not have to build a whole HTTP-client, as Linux already has one. I have written a small tutorial about that: Running Node.js on Arduino Yun.

All of that worked fine – in the lab. Using the sensor networks in the wild (well, in my house), I found it very difficult to debug the system. In order to save power the nodes do not have any LEDs, Display, whatever. I added some LEDs to the Arduino Yun that showed it’s state and if sensor data came in. But all in all it did not really help. I found sensor data in the cloud, but not from all nodes. And I could not really see the routing in the nRF24L01+ network. Attaching displays to the sensor nodes has not been an option due to power restrictions. I had to add a display to the hub. That would give me the option of adding some sort of user interface to it. But Arduino Yun only has 2K SRAM, and adding a display and it’s quite large driver code I ended up with not enough SRAM left. I could optimize everything so it perhaps would fit, but I would not have any room to add a UI to the hub later on. I have been quite disappointed about this limitation. I think the Yun should have built with a beefier Arduino-MCU. It should be possible to drive a display trough the bridge from the Linux side, but that would be way to slow. Although I really liked the idea of the Yun, it did not fit my needs.

Teensy is here to help

Searching for an Arduino Compatible small device Google with tell you to have a closer look at: Teensy. Teensy is just an amazing piece of hardware, created by Paul J Stoffregen. Paul did an amazing job with Teensy, especially the latest version 3.1. Teensy ist very small. If you find an Arduino Nano or Micro Pro small, you will be amazed how small Teensy really is. And it’s very, very powerful. Teensy features an ARM Cortext MPU with 64 KB SRAM and 256 KB Program memory. That is a lot of space and enough to do a lot of cool stuff. What I really love about the Teensy is how bootloading it is solved. I had a few issues with programming Arduinos. Teensy features a tiny uploader software, that is either triggered by the Arduino IDE or by pressing the reset button on the device. And uploading new code always worked. I really love that. Just install the Teensy Hardware Plugin in your Arduino IDE 1.0.x (it does not support 1.5.x at the moment) and you are good to go.

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Custom LCD Controller for Printrbot Simple (Metal)

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.

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Getting started with Printrbot Simple Metal

Printrbot Simple Metal Black

My DIY-Wireless-Home-Automation-System requires various nodes to be placed around our house. Having kids and a wife, there is no way around building nice looking enclosing for my stuff. So I decided to invest into a 3D printer. It took me some time browsing the web to find what I was looking for. I really want good quality prints. And as my primary interest is electronics and not 3D printing, I wanted a machine that runs out of the box and does not need a lot of preparation before each print and various reprints until you have printed a piece that is ok.

As I did not want to spent too much money on a 3D printer I bought a Printrbot Simple Metal. As you browse the web you read a lot of very good things about this tiny (well, not really) machine. And I tell you the same. This machine is really very, very good. But there is a major fault with it: It’s not plug and play. But it’s so close! The software is good, and the hardware is very, very good, too. Even the Getting Started Guides on Printrbots Website is quite good I think. But there are some minor Bugs that prevent a hassle free start – well in my case, and as you are reading this I think you have problems, too.

I must admit that I purchased the assembled one. If you are having problems your job is harder as you could have built something wrong. Either way, perhaps you did everything correctly and now you are running into the same issues that you will have even with an assembled one.

What I really do not understand is that there are so many comments and forum posts with people running in the same problems over and over and it all comes down to faulty getting started guides and other minor documentation bugs. And they have not been updated till now. But I am here to help!

Here is my own getting started guide. But I will not write down every little step. Instead I will give links and will comment on the bugs, issues and solutions I have found while following the official guides.

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A DIY cloud centered, iOS controlled, Arduino based Home Automation System – Part 1

Wireless Node Prototype

There is a lot of buzz around things like “Internet of Things”, “Home Automation”, and “Smart Homes”. One reason for buying into commercial home automation systems is energy savings. At least that is often the main marketing message for commercial products. That is not true, as recent studies found out, and it is not my main motivation to build such a system.

A lot of commercial systems use Bluetooth (Low Energy) Systems zu drive their home automation solutions. You have a device, and an App that is connected to this device to control it. Sometimes, you have an array of devices, that are connected to a hub often with Zigbee based Mesh networks (so your Smartphones App only needs one connection). One example for that is Philips Hue Light System. Apple realized this is a problem as no one wants 10 Apps to control different aspects of their home and introduced HomeKit. While this really sounds interesting on iOS-Controller side, it remains to be seen how this works out on devices and compatibility (and price of course).

When I first got my Philips Hue System I have been impressed and loved it from day one and do so till today. But we have not installed it in every room. And controlling it with your phone is great, but it’s also tedious to pick up your phone to turn on light in a room you are just entering and turning it of when leaving the room. We often end up using the light switches on the wall, which kills that whole Home Automation thing as lights switched off on the wall cannot be turned on again wirelessly.

IFTTT  and Philips Hue: just magic

Things got really interesting when I tested IFTTT.com. What a great service. With “If This Then That” it’s possible to interconnect different web services and trigger actions based on data or triggers of other services. I created a very small receipt turning on my Philips Hue lights at sundown and turns them off at 1 o’clock in the night as a fallback if I just forget to turn lights off when I go to bed.

And it really works well most of the time. And that is really magic. If you have Philips Hue installed. Give it a try. It’s magic. Yesterday I have cooked and thought that it’s about time to turn the lights on, a few seconds later they turned on. Without pressing a key. Without picking my phone. On cloudy days, you sometimes have to turn lights on before sundown, because it’s just kind of dark. This is where large scaled systems like IFTTT have not enough details.

That’s been the moment where I decided to make my own DIY cloud centered, iOS controlled, Arduino based wireless Home Automation System.

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