MightyOhm » Microcontrollers

Geiger Counter Kits are (finally) in stock!

Jeff — Wed, 31 Aug 2011 23:50:31 +0000

Geiger Counter kits are now in stock! You can order one below or go visit the Geiger Counter kit page to learn more.

There are currently three ordering options:

You can buy the complete Geiger Counter kit with a tested, known good SBM-20 Geiger-Muller tube included (recommended).
You can buy the same kit with all parts except the Geiger tube (in case you already have one).
Or, you can purchase a bare PCB only (for experimenters).

You can select one of these options below:

Shipping is via USPS Priority Mail. Allow 1-2 weeks for order processing and delivery.

The Amp Hour #43

Jeff — Tue, 17 May 2011 13:58:04 +0000

The Amp Hour #43 — Audacious Arduino Arguments

Our first four-way podcast! Listen to me, Chris, Dave, and Jeremy chat about Arduino, high altitude balloons, hackerspaces in universities, the Google ADK, and the Maker Faire Bay Area.

Kudos to Skype for enabling us to actually pull this off!

Another guest appearance on The Amp Hour!

Sign up to be notified when my book is published!

Jeff — Thu, 14 Apr 2011 06:59:14 +0000

The “Soldering is Easy” comic book that was released on Monday will be included in a cool book that Mitch Altman (@maltman23) and I are writing about How to Make Cool Things with Microcontrollers (For People Who Know Nothing). It will be published by No Starch Press later this year.

If you would like to be notified when the book is published, please submit your e-mail address below.

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Announcing the “Soldering is Easy” Complete Comic Book!

Best book to learn C?

Jeff — Mon, 04 Apr 2011 06:14:27 +0000

If you could recommend one book to a total beginner who wants to learn how to program in C, what would it be?

It shouldn’t be microcontroller-specific (more general is better), but it does need to make sense to someone with zero programming experience (in any language).

(Myself, I started with K&R, although I had some experience with BASIC (on the C64 and Apple II), Logo, and shell programming before that.)

Jan’s Wifi Radio has a modern look

Jeff — Thu, 24 Mar 2011 21:16:25 +0000

Jan Wante made this gorgeous Wifi Radio with a modern look. It is based on my original Wifi Radio tutorials.

Not content to simply duplicate my work, he added a few creative twists of his own, including a custom handmade case made of alucobond, MDF, and real wood veneer that gives his finished radio a nice, modern look. Inside, a hacked WL-520gU wireless router running OpenWrt runs the show and an ATmega microcontroller programmed with BASCOM interfaces with a rotary encoder and graphical LCD display.

The very impressive result is shown in this video:

Nice work, Jan!

HV Rescue Shield now works with the Arduino Mega

Jeff — Wed, 16 Mar 2011 21:38:38 +0000

Thanks to John, of the ATX Hackerspace, who loaned me his Arduino for testing, the HV Rescue Shield now works with the Arduino Mega.

I had to create new byte read/write functions for digital lines 0-7 because they are implemented very “differently” (and I don’t mean that in a good way) in the hardware for the Mega. If you’re interested in how I did this, check out the new version 2.12 Arduino sketch and the new mega_data_read and mega_data_write functions.

To use the HV Rescue Shield with the Arduino, first download the revised sketch here. Set the MEGA #define to 1 and compile/upload the sketch to your board. Make sure you have the Arduino Mega selected in the Arduino Board menu, or the sketch won’t compile.

The Mega has more pin headers than the Rescue Shield, so be sure to install the shield all the way to the left, as shown here:

If you experience any problems with the HV Rescue Shield and the Arduino Mega, please report them in the support forum.

The Amp Hour Episode 29

Jeff — Wed, 09 Feb 2011 03:37:37 +0000

I’m happy to announce that I have again been given the privilege of co-hosting The Amp Hour, this time with Dave Jones of the EEVblog! Chris Gammell is away this week recruiting bright young engineers ~~into slavery~~ to join his company, so I was given the guest spot. This is my third time on the show.

If you haven’t heard of it before, The Amp Hour is “an off-the-cuff radio show and podcast for electronics enthusiasts and professionals.” I listen most every week and would recommend it to anyone who wants to hear a humorous and off-beat take on electronics engineering.

Check out Episode 29 – DJ and Jazzy Jeff and all the rest of the episodes at The Amp Hour.

HV Rescue Shield 2.1 Now Shipping

Jeff — Mon, 07 Feb 2011 07:27:20 +0000

I have good news. The latest and greatest version of the HV Rescue Shield is now available!

Version 2.1 contains a new and improved 12V switching circuit that resolves an issue reading/writing to parts with certain startup timer settings. This issue affects all previous versions of the Rescue Shield kit.

I have kits in stock and ready to ship this week. If you have been waiting for the new release, you can place an order now.

Note to HV Rescue Shield 2.0 customers: Because the startup timer issue was identified so quickly after version 2.0 was released, I am offering a free upgrade for all customers who purchased a version 2.0 kit. Please contact me to arrange for a replacement. This offer only applies to HV Rescue Shield 2.0 customers.

HV Rescue Shield Update #3

Jeff — Tue, 25 Jan 2011 19:46:15 +0000

A quick update on the HV Rescue Shield:

About a week ago, I completed testing on a new switching circuit that allows me to leave the DC-DC converter on full-time and switch the RESET signal very quickly (risetimes in the microseconds). Now there shouldn’t be any more issues getting parts with zero SUT to enter HVSP/HVPP mode.

It’s taken a lot longer than I expected to get to this point, but the results look very good. I have had 100% success reading/writing all parts I have tested.

PCBs are on order and due to ship by the end of the week. Assuming the layout is good and I didn’t just order a large batch of stylish (but small) coasters, I should have kits in stock again by the end of next week.

Watch here for updates, and my apologies to everyone who has been waiting on a kit – new and improved kits should be available soon.

Update 2/1: PCBs came in while I was away last week, and are currently being held at my local Fedex office, which is closed due to the power outages that are affecting Austin today. Apparently Austin does not handle prolonged sub-freezing temperatures very well. As soon as I can get my hands on the boards, it should only be a day or two before kits are available again.

HV Rescue Shield 2.0 status update

Jeff — Wed, 12 Jan 2011 18:45:07 +0000

Just before the holidays, an issue with the Rescue Shield 2.0 (which I have at times referred to as “2.x”) was identified. The issue involves problems reading/writing to parts that have certain startup timer (SUT) fuse values set.

There is some more information about the issue on the forums and in a previous post here and I created a Known Issues page on the wiki.

While this issue will not affect most users (this is why no one, including me, noticed it until now), I am currently working on a fix. Initially I had hoped that I could fix the problem in software, but after spending far too much time pursuing that approach, I have decided to address it with a hardware change instead. This should make for a much more robust solution. I’m in the process of revising the hardware this week and hope to release a new version of the shield in the near future.

As soon as I heard about the issue in December, I stopped taking orders for Rescue Shield kits. Kits and PCBs will show up as out of stock until I release the new version.

I’ll post another update when I have an estimate of when kits will be available again.

Thanks for your patience!

Issue with Rescue Shield and targets with SUT = 0ms

Jeff — Tue, 21 Dec 2010 21:01:55 +0000

HV Rescue Shield 2.0 customer Matthew Beckler has uncovered an issue that affects all variants of the Rescue Shield.

Long story short, if the target AVR is configured for a fast internal clock and zero startup time (eg. LFUSE=0×62 on the ATtiny13A gives a 9.6MHz clock with 14CK +0ms startup delay), then a slow rising edge on the 12V RESET signal from the Shield results in the target not entering or dropping out of HVSP or HVPP mode. The symptom is that regardless of the fuses stored on the target, the Rescue Shield fuse reads return 0xFF. In addition, the fuses can’t be changed.

I am currently investigating a solution. There is more information about the issue and updates regarding debugging in the HV Rescue Shield support forum.

New Product: HV Rescue Shield 2.0

Jeff — Mon, 13 Dec 2010 22:03:28 +0000

The HV Rescue Shield 2.0 is a high voltage parallel mode fuse programmer for Atmel AVR microcontrollers.

It currently supports a wide variety of AVR chips, including the 28-pin ATmega48/88/168/328 series, the 20-pin ATtiny2313, and many 8-pin ATtiny devices (such as the ATtiny25/45/85 and ATtiny13A). A list of supported devices is in progress, but the Rescue Shield supports many more devices than those listed on the wiki.

The HV Rescue Shield 2.0 is in stock and ready to ship today! Scroll down to place an order.

New in release 2.0:

Support for 8-pin ATtiny devices that use High Voltage Serial Programming (HVSP) mode!
Mode selection at startup so you don’t have to recompile the Arduino sketch to change parts.
More reliable HFUSE burning on all HVPP targets.
Numerous minor bug fixes and speed improvements to the code.
Reduced price, kit is now only $19.95 (was $24.95). This means the kit is lower cost, but with more supported parts!

Requirements:

A working Arduino (tested with Arduino Uno, Duemilanove and Arduino NG)
A computer with USB and the Arduino IDE installed (tested with Arduino 0021)
A soldering iron and basic electronics assembly skills

What you get:

A high quality printed circuit board with the DC-DC converter preassembled, as shown below.
All other components needed to build the kit
An Arduino sketch, assembly instructions, Eagle schematics and layout files.

Here is a snapshot of the components included with the kit.

How to Order:

Visit the HV Rescue Shield 2.x product page to place an order.

Microcontroller Mondays @ ATX Hackerspace

Jeff — Mon, 13 Dec 2010 17:18:07 +0000

I am hosting a weekly microcontroller study group at the ATX Hackerspace. If you are interested in learning about microcontrollers in a casual setting, come on by at 7:30pm tonight.

Tonight at 7:30pm we will hold our weekly evening of microcontroller exploration, otherwise known as Microcontroller Monday.

The idea is not to have a fixed agenda or format. This is not a class, though I’m pretty sure everyone who comes will learn something.

Some examples of things we might do on MM:

- start learning about the MSP430 and play with the MSP430 launchpads at the space
- have Danny and Christian teach us about the dsPIC
- build some USB devices and play with LUFA (the open source AVR USB library)
- corrupt Arduino users with the notion that there is something beyond analogWrite()
- discuss related topics, like circuit design, PCB layout, etc.

If any of this sounds interesting, consider stopping by tonight.

I plan to be at the space from 7:30 to around 10PM, but that doesn’t mean people can’t start hacking earlier or stay later. While this event is open to non-members, since a member needs to be present to keep the space open, non-members should adhere to the 7:30pm – 10pm schedule.

ATX Hackerspace maintains a calendar so you can stay up to date with this and other goings-on at the space.

HV Rescue Shield 2.0 update

Jeff — Fri, 03 Dec 2010 00:56:40 +0000

Version 2.0 of the HV Rescue Shield (I decided to drop the ‘AVR’ from the name) will add support for high voltage serial programming (HVSP) and 8-pin parts like the ATtiny13A.

Boards are due back next week, components are on order, but there is still code to write.

Back to work!

New Product: ICSPOV

Jeff — Wed, 01 Dec 2010 22:59:30 +0000

The ICSPOV is a 6-pin ICSP programmer adapter for the Adafruit Industries miniPOV3.

The miniPOV3 is a great kit, but it has one big problem – if you want to change the pre-programmed message to something else, you have to use a crude programming interface called DASA, otherwise known as ‘bit-bang mode’. This wasn’t a problem back when most PCs and laptops came with serial ports, because most COM ports could handle DASA just fine. However, these days, computers don’t come with serial ports. Instead, USB-serial adapters are the most common way to add a COM port to a newer laptop or PC.

DASA does not like USB-serial converters. What used to be a cheap, easy programming method is now so slow and unreliable on most USB-serial converters that it is almost unusable. What was a fun and easy kit is now much less fun when it comes time to change the displayed POV message. Programming a new message into the miniPOV can take over five minutes depending on your operating system and serial port setup. That is, if it works at all.

Introducing the ICSPOV:

The ICSPOV aims to solve the problem of programming the miniPOV3 by providing a way to connect a proper AVR programmer instead of using the DASA interface. The ICSPOV adapts the 9-pin serial connector on the miniPOV3 to a 6-pin ICSP header used by many other AVR projects and supported by most low-cost AVR programmers. After making one simple modification to the miniPOV3 and editing the project Makefile, an ordinary AVR programmer such as the Adafruit USBTinyISP can be used to program the miniPOV.

Programming times of several minutes are reduced to seconds.

The ICSPOV should work with most 6-pin AVR programmers. It has been tested with the Adafruit Industries USBtinyISP as well as the Atmel AVRISP mk II, as shown below.

The ICSPOV is completely open source. Schematics and layout files are available for download.

You can purchase a kit on the ICSPOV product page.