I’m taking my loving, talented and overworked wife on a short road trip. We leave this morning and will return Sunday. Orders placed today, Friday, 28 January 2011 will ship Monday, 31 January 2011. If you placed an order yesterday, Thursday, 27 January 2011, your order is on its way to the Post Office, but you will not receive a shipment notification (from me) until Monday.
MAKE vol 25 features a little article I wrote about building a “Breadboard Arduino”. You can buy a kit that contains all the parts for $40. Click on the giant “Buy Now” button to order one today!
The kit includes everything you need: a solderless breadboard, jumper wires, a pre-programmed ATmega328P with pin label, USB adapter and basic components to perform the basic “software experiments” in the article. You need: a computer with a spare USB port that can run the free Arduino IDE software and a USB A to mini-B cable.
The first 99 buyers also get the “Li’l Larson LED Scanner Expansion Pack”, for free! OK, it’s just 5 red LEDs and some more jumper wires but you do get a really nice, custom laser-cut LED bezel for maximum Cylon (or K.I.T.T.) action!
What is a 12V Dimmer Kit V2, you ask? It’s an especially efficient PWM (pulse-width modulation) controller for 12V loads up to 60W. Use it to variably dim LEDs or control the speed of DC motors. It comes as a kit and you solder it together.
Have a look at the User Manual and Assembly Instructions (1MB PDF). I’ve also got a schematic diagram available for your inspection. The source code for the microcontroller is also freely available, if you’d like to tinker around with its innards, or just take a peek.
The 12V Dimmer Kit V2 is both new and improved. “How can it be both?” you ask. I’m glad you asked. This is a redesign of of my previous 12V Dimmer Kit and includes several improvements in both the hardware and the software. I’ve also added some completely new features that were not present in the original kit, so that makes it new as well. See? Aren’t you glad you asked?
This kit started out as a simple dimmer for one of my IR Spotlights. A customer in the UK wanted to photograph bats at night and needed a variable infrared source for his camera. I built two of those dimmers and they worked well for the intended purpose, but I was never really sure how well it would work in other applications. Another customer showed me a kit he was buying from overseas and I thought I might try making my own. It worked pretty well at about 25W and sold out every time I built a batch of them. Unfortunately, I had designed in a component that was once cheap & plentiful in the surplus chain but one day ran dry. It took a long time to find an adequate replacement that I could count on. Once I did, I sat down and started designing the new version, hoping to basically duplicate the success of the previous circuit and make a couple of small improvements while I was at it.
Then yet another client wanted a custom version of the dimmer that was operated by a simple push button instead of a dial. I could get so much work done if it wasn’t for these pesky customers! (tee hee hee) The push button version worked well enough, and it made me want to add that as a feature to the existing dimmer kit. That was kind of tricky! The upshot is that the new (and improved!) 12V Dimmer Kit V2 will work with either the dial adjustment (a potentiometer) or the push button – or both.
I also wanted to up the power-handling capacity to at least 50W. I added an extra amplifier stage to the output driver, and was able to get the new kit to handle up to 60W without a heat sink on the output transistor. It gets a little warm but not much (i.e., you can leave your finger on it).
Thanks to all my beta testers for helping me test the unit in the field, point out obvious bugs and even blow units up. Your help and attention to detail (and abuse of poor, innocent electronics) has made this a much better product than I could have possibly made by myself.
Let me know what you think in the comments.
Recently I’ve described myself as a “full-time freelance writer and part-time student”. This semester (Fall 2010) it turns out I’m a full-time student. I just counted up my hours and after exhausting all the available digits, I removed one shoe and discovered I was taking 14 hours, which most people consider full-time status. I have had the pleasure of knowing younger, more ambitious students who were taking 20 and 24 hours in a single semester, but I think we can agree those people are crazy. Or doctors by now.
After reviewing my scholastic accomplishments with one of the fine counselors at the local community college, it occurred to me that I could graduate in the spring if I just worked a little harder. I must admit that this idea holds a certain amount of fascination.
Wish me luck!
While waiting for my 12V Dimmer Kit PCBs to arrive, I spent a little time building yet another Cylon-style LED scanner. This time it has 12 LEDs! That’s more than 5! Quick, someone do the math!
Here’s a short video showing how it’s coming along so far. It’s still on a solderless breadboard at this stage. I’m thinking about a PCB that’s about 4 inches long and maybe one inch across, or perhaps slimmer. It should run on two AA batteries.
Let me know what you think in the comments!
Here is an actual photograph of an actual prototype of the long-awaited updated version of my ever-popular “12 Volt Dimmer”. It’s an especially efficient PWM controller for 12VDC loads up to 60W. The previous version was only rated at 25W, so this is a big improvement in capacity. Also, I’ve added an extra pushbutton to allow cycling through preset power levels, which are currently 1%, 10%, 25%, 50% and 100% and back to off again.
The 12V Dimmer kit will be available in two to three weeks (*crosses fingers for luck*) for only $14.95. The production version will be much more attractive than this prototype, with a real soldermask and silkscreen.
Since the power terminals are unlabeled on this prototype, I’ve included this photograph to illustrate the proper connections for both power and load.
You can control a *LOT* of LEDs with this kit, as well as motors and fans as a speed controller. There are actually a lot of applications for a simple circuit such as this.
All the design files, including the schematic and microcontroller source code will be released when the kits are ready to ship. I have several units in the field being evaluated by my trusty beta testers. Hopefully there will not be any big surprises between now and the launch date.
I’ll be closed for business from Wednesday, 30 June 2010 and back to work on Monday, 12 July 2010. Any orders placed during that time will not be shipped until I return.
We’re packing up the family and heading north to get out of this Texas summer heat, because we heard “it’s cooler near the lake”. See you in a couple of weeks!
Look what come in the mail today! It’s a bag full of Chibi Dale buttons from my friends at Kwartzlab, a hackerspace in Ontario, Canada. Thanks, guys!
I would like to be thought of as a “tool-using animal”. I have a deep appreciation for well-designed and effective tools. Likewise, I have a distinct aversion to low-quality or ineffective tools. I try not to be a “tool snob”. There is truth in the old saying “It is a poor craftsman indeed who blames his tools”. Yes it is also true that “You can build a doghouse out of anything”. So it’s important to me to use the right tool for the job, when it matters, as well as have a fundamental understanding of what constitutes its proper use.
My online store is open once more. Please feel free to visit and even buy an item or two, should the fancy strike you.