The Celtic Engineer is a weekly newsletter produced by Celtic Engineering Solutions. We hope you enjoy it. If you have any suggestions for topics, would like to give feedback or want your email added to the distribution list please send an email to
If you can’t buy it, build it
Many times, in engineering, you need a little tool to make your life easier. Just as often that tool does not exist. Too often we muddle through with the best that we have to get the job done. That is fine if the task you are working on is unique, but if you are likely to do it again or if the task will be prolonged it might be worth your time to build your own tool.
I spend a lot of my time laying out schematics and then making printed circuit boards from those schematics. One of my favorite tools is Altium, no secret. If you know me at all, you probably already knew that. I like it because it makes my life easier. I am not suggesting that if you don’t have Altium you should go out and start writing code to make your own. You must know your limitations. But there are things we can do in our daily routines that will make things easier. And easier is more efficient which relates to dollars and worth and before you know it you’re valued by your employer.
Just how big does that connector need to be?
A few years ago, I started using microcontrollers from the Texas Instruments MSP430 family. Coming from the Atmel chips I was blown over by how big the JTAG connector was. Does it really need to be that big? Are we even using all those pins? Wow!
So many of the boards I find myself working on are tiny, so when your programming connector is a significant portion of the board size something is not right. It did not take me long to decide to make a small jumper board. The idea is that the TI programmer plugs into one side and then there is a smaller connector on the other that plugs into my target board. A flat ribbon connector running from my jumper board to the target board is adequate. I can select which signals I really need for my application and ignore the rest.

The photo in figure 1 is what I came up with. The gray connector on the left is the giant 0.1-inch 14-pin connector. The small black one on the right is the 0.05-inch 10-pin that I really like to use. I like it because it is easy to get a flat ribbon connector that plugs into it. It also is keyed so I don’t accidentally plug it in backwards when it gets towards the end of a long day of programming and everything is a bit fuzzy (I am sure that never happens to you). Mostly I like it because it is about ¼ the size of the normal TI connector.

Figure TI JTAG Adapter board

In a production board, there will be no JTAG connector because we will program the MCU chips before they are placed on the board. The time when I use these is when I am developing a new product, a prototype. Things are not optimized and space is really precious, so why waste it on a connector.

The square wheel
What repeated tasks do you face that could be made simpler by a small side project? I have one I have not gotten around to, I often need to do a rough calibration on a piece of equipment. This is a prototype and does not need high accuracy, no certificate please. What I need is a variable load that will allow me to pull somewhere between 500uA and 100mA. Now that wouldn’t be hard to do. I usually kludge something together around the lab and make it work. The point is, I have done this a dozen times and will probably do it again in the near future. It is time to make something or go and buy something.
Productivity can be increased dramatically by finding these bottlenecks and making them go away. It is probably not worth spending $1000 on something I will use once a year for an hour. But if it becomes a task that keeps coming up and it takes a lot of my time, then I should find a better way and do that from now on. You should too.
Final thoughts
This newsletter is sponsored by Celtic Engineering Solutions LLC, a design engineering firm based out of West Jordan, Utah, which can be found on the web at: You can find the newsletter on the company blog, LinkedIn or in your inbox by subscribing. Send your emails to The Celtic Engineer at:, with the subject line SUBSCRIBE.