New hosting

We have moved teho Labs to a new host.

We know there are some bugs in the wiki/docs section with formatting. The backend for the wiki was updated and the old CSS scripts are no longer exactly compatible. A quick and dirty edit was made to get things 90+% functional, but there could be bugs. The contact link and form are toasted. We mostly got spam though these.

If you notice problems, leave a comment on this post for feedback. It will be left open to the spammer for a few months to allow for any bugs noticed to be corrected.

quietPower mk I beta

I’ve been working on this a while: a clean bipolar power supply. This is needed to supply power to things like amplifiers that require symmetric power rails to function. It is based on LT3439. Check out the video for a quick into. More information on this project is in the doc section at:

The main performance write-up is here:

Hopefully I will have time to finish the design soon. BOM, and design files will be released then.

Discussion of this design is over at Dangerous Prototypes.


End of development board era

As alluded to teho Labs is getting out of the low cost development board market at least for now.

As of today sales of the ARM development boards are being halted.

teho Labs will continue to be a source of information and projects, so feel free to check back in.

I have ideas for no less than 5 major projects at the moment. With the completion of my PhD there may actually be time to complete major projects again in the near future, so I hope to show off some interesting in early 2013!

Plans for the lab

Hello everyone. I thought I would take a moment to give you guys the scoop for the plans for teho Labs. I know this year as been horrible for updates.

We live in a golden era for micros, you guys out there have a lot of choice of development boards and good ones at that.

While my development boards remain excellent value compared to the official Ti ones, we now have a lot of choice in the ARM space that we didn’t have when I started releasing boards way back. As a result I’m not going to make development boards the focus of teho Labs going forward.

Instead the focus will be tools. This was always part of the plan. Eridani was actually designed to be a GPIB controller, but when I polled the community I found few people who knew what one was! Since then there was a thread at dangerous prototypes that showed that some folks did need one after all…

Nevertheless, tools are certainly the name of the game going foward. FPGAs, uC, and lots of analog probably. I have designs for lots of analog stuff in the works, but what I can release, how, and when will depend on my employment going forward. Analog design requires more care and knowledge to do well.

I also may move to a fulfillment model like dangerous prototypes uses once I can absorb the cost of possible failures or establish a good revenue stream to fund the lab.

Changes are coming. Things will be settled and headed in the new direction before the end of the year.


KiCAD libraries

We have had a number of requests for board files, but never felt comfortable releasing them because the KiCAD libraries they are based on were rather messy.

It is likely the old projects will never be released in full open format simply because we don’t think the board files would make any sense to anyone else.

To solve this issue, we have started new KiCAD libraries with some standardization on how things are named.

They will be updated to match the latest project that is released.

Essentially there are two classes of parts through hole (TH) and surface mount (SMD). There are two flavors of parts standard footprints (SOIC8, 0603 things like that), and not standard.

Therefore there are 4 libraries. If a part isn’t known to be standard it will go in the non-standard library. Most parts will have a default package for PCB-CV, other packages may exist but you are advised to check the pinout if you don’t use the default package

The non-standard part naming convention is:


e.g. opamp_Ti_OPA350


CPiLD is a CPLD board for Raspberry Pi, it also has an I2C buffer chip.

I would say the major points are:

  • 5 volt tolerance
  • breakout to breadboard
  • I/O expansion
  • Interface conversion (e.g. SPI to I2S)
  • education: learn HDL or logic circuits

The board is based on XC9572XL in a 64 LQFP package.

Check the docs section for a port of the XSVF player for Raspberry-Pi and more detail on the board.

The default image for the CPLD is a SPI bus expander buffer. It buffers all the I/Os and adds 8 inputs and 16 outputs.

If you think you would want one, leave a comment. If there is enough interest there will be a kickstarter for them.

Raspberry Pi Arrives

I ordered a Raspberry Pi back in March (or was it the last week in Feb.) the day it was put on sale via Newark. I actually did it while I was at a conference. After what was a rather lengthy wait, it arrived just about 3 months later.

To be honest Beaglebone is more open source than Raspberry-Pi, it is also faster probably at least for general purpose stuff. What it doesn’t have though is HDMI on board or a price point of 35 dollars. You’ll need a 10 dollar SD card also so really 45 dollars is what a R-Pi costs to deploy.

For some things having real time access is more important for that Procyon and the ARM boards I build are better. They have a lot of resources and can do complex things like FLAC decoding, and they have pretty high memory bandwidth for a single task, again taking Procyon as the example it does 50 MB/s to SDRAM.

However, not having to do much but download a package of some complex library is a lot easier so I fully expect R-Pi to become the dominate internet electronic project gateway device for the DIY community.

I will likely be doing some add on boards for R-Pi, so stay tuned.

If you want some more of my thoughts on R-Pi in relation to use and hardware check out my post on Dangerous Prototypes’ forum.

Die spamers

Although there haven’t been a lot of recent posts the spam bots are equally happy to crush all the old ones… This made the ratio of spam to real comments explode as of late.

Since everything still is manually moderated, this creates work. To help the situation comments have been closed on all the old posts. If you need to talk about one of them be sure to write using the contact form!

There are things cooking, but I’m not ready to talk about them yet. Stay tuned, it shouldn’t be more than a few weeks before I can give more details.


PCB builds

Among the PCBs I got back was a version of BasicUART V2 that uses FT232RL in place of MCP2200. The previous version of this design had a problem with a zone not connecting to a GND pin, which caused it to be flaky at best.

I built up one last night and it worked nicely. I will get to updating the docs and producing a few of these in the near future.

Another design in the PCB batch was a high speed DAC conversion board. This board had some issues. First the footprint for the DAC chip wasn’t correct (I needed the wide version but used the narrow version opps!). Second the opamp circuit was unstable. I was able to hack fixes for both onto the PCB to do some testing. After the fixes the output was not bad at all. It still needs improvement and that will likely require another 2 PCB iterations for what I have in mind to really test fully.

MSPism got a minor tweak to its design, which looks fine but still needs to be tested. I have some firmware written for MSPism but it isn’t what I envisioned as the final features which is why it still hasn’t been released and put on sale. If you feel strongly I should just release what I have done, sound off.

The other boards have yet to be built up for testing of any kind. One of them is for a contract and the other is a new design, for an old idea.

An update!

Yep I’m still here. Quite busy but still working on PCBs and designs as time permits. Just as a short update to wet anyone’s appetite, I got 60 PCBs in the mail yesterday with a few designs among them. In my disarray parts to complete some of them are not on hand this weekend but they will be by next weekend… Stay tuned!