Second mirror laser alignment jig for Laser Cutter/Engraver

Recently I had some minor issues with my Shenhui 50W eBay laser machine. Laser beam was not reaching 3rd mirror in the center, so I had to re-align 2nd mirror to make corrections.  Normally this is a long and tedious process of moving laser head to different positions, attaching sticky tape, firing laser and then trying […]

April 7th, 2015|diy, How To, Laser machine|1 Comment

DIY Pin Table for laser cutter

If you just doing laser engraving, you don’t really need to worry much about supporting your objects, however when you cutting them, it’s another story. Laser beam slices thru material and continues to whatever lies beneath. If it’s just plain metal table it will reflect back scoring or melting your object from underneath. This is […]

March 13th, 2015|diy, How To, Laser machine|3 Comments

New Project: Small Solar off-grid system

About this article.
In this blog post I’m attempting to distill weeks of online research and my own experience of building small off-grid solar system into short and sweet blocks of information. I’m not going to go into excruciating details about how technology works (i.e. AGM batteries vs. flooded).  Instead I will provide links to very useful articles. If you don’t care about how and why parts, feel free to skip summary paragraph where I provide all the components I got to do build the system.


October 30th, 2014|diy, tips|0 Comments

Controlling Roomba 550 series w/ Arduino

I had my Roomba 551 for a long time (over 5 years). This model was only sold in Costco, but it’s basically a 550 model, slightly repackaged.  It was a somewhat lousy vacuum cleaner, as it would require preparing room for it by blocking access to shaggy carpet where it would get stuck and removing all cat toys on which it would usually choke. So it’s been collecting dust for a a while (passively). At some point few years ago before I learned about Arduino I’ve got a “Hacking Roomba” book and tried to … well hack my roomba. I wanted to turn it into a mobile camera. I bought a RooStick which was DIN8 to USB interface (no longer sold) which allowed to connect roomba to computer. I even built my own roomba interface cable from old keyboard cable. However it got me nowhere at the time.

Recently having some success with Arduino, I wanted to build a moving camera platform to watch over my cats while I’m on vacation. Plan was to use Roomba as mobile platform and power supply. Since it can supply over 16 volts, I should be able to power WiFi IP cam, Arduino and small wireless router.  Router would be used to control Arduino via internet. Because I already had ethernet shield and didn’t want to spend lots of money for WiFi shield I found this really cheap and small router TL-WR703n. With custom OpenWRT firmware it can serve as a bridge, but also because it has USB port I can connect WebCam to it (althought since I’ll be using motorized IP cam, it’s not really required).

But firs thing I need to do is to learn how to control Roomba with Arduino.


May 27th, 2013|diy|0 Comments

LM386 based portable audio amplifier under $3

If you project needs small battery powered audio amp nothing beats LM386.  It can work with voltage as low as 3V (battery powered) and provided pretty loud yet good quality sound.  We are talking around <1 Watt of course, but it’s sufficient for most little gadgets and/or toys.

And best part you build one for under $3. Instructions, part list and video after the break.


December 30th, 2012|diy|0 Comments