Viswa found this online video course, “Embedded C Programming with ARM Cortex-M.” The series of videos from Modern Embedded Programming is designed to acquaint beginners with C programming with modern MCUs such as the ARM Cortex-M. The examples use the Stellaris Launchpad and the IDE is the IAR embedded workbench toolset evaluation version (code size limited, but not time limited.)
Via the contact form.
Today we recorded and edited the solder paste dispenser video.
Work continues on the Bus Pirate v4 UART debugging mode. We fixed yesterdays bug and after some code cleanup it will be committed into our SVN tomorrow. There will be two modes available. One is activated at compile and completely disconnects USB communication. While the other is accessed by sending command ‘q’ while in HiZ mode. This will enable parallel communication through both USB and UART.
Meet Powah, a little power on/off toggle with an indicator LED. It uses a pair of Schmitt triggered inverters to debounce the button, and a P-channel MOSFET to switch the power on and off. The board is designed to be plugged into a breadboard.
It is designed to mount on one end of my breadboard, so as to reduce the wear and tear caused by excessive insertions of power bus leads. The board is approx 1 cm^2.
While circuits can’t be copyrighted, they can be patented. Mats spotted this simple undervoltage indication circuit that is supposedly covered by a patent. As always the devils are in the details, so a specific non-obvious aspect of the circuit may be the patented component. Imagine how difficult innovation would be if there were a patent war over simple stuff like this though. Ugh.
Without a doubt the solder paste dispenser is a cool tool. Compressed air hisses and solenoids crackle while precise amounts of solder paste extrude into beautiful droplets on a PCB. A few minutes with a paste dispenser saves $15-$25 (or more) on stencils, a life saver if you want to pick and place a one-off prototype. Only Akiba’s CNC milled stencils seem to beat it in speed and convenience.
Our dispenser is a random-name 986A, which seems identical to the more widely available 983A. There’s dozens of brands that all look similar, and generally use the same model number as a Hakko tool. Qwik, Best, Aoyue, Gayoue, Qinsi, Gold, the list goes on and on. Check it out in the video above, and continue reading about it below.
Continue reading “WORKSHOP VIDEO #54: 983A/986A Solder paste dispenser”
Matthew Zaleski found this resource posted by National Instruments. It’s a fairly detailed whitepaper titled “Understanding and Characterizing Timing Jitter”. This looks like a good resource for anyone doing high-frequency communications.
Via the contact form.
After two DIY Li Ion chargers this week (first, second), here is a lithium iron phosphate (LIFePO4) battery charger. These batteries are a safer cousin to the standard Li-Ion batteries, but sacrifice some of it’s energy density for the safety. The charger above is designed around the PIC12F510 microcontroller which implements a rudimentary USB powered pulse charger.
We designed Sick of Beige cases and the accompanying PCB standard sizes because we were sick of plain beige boxes. If you, however, are not sick of them, here is a beige box that fits the DP5031 standard PCB size. It will need an extra central hole in the PCB for the enclosure to be screwed shut.
You can get Sick of Beige cases in 13 different standard sizes for $3 at Seeed.
Prepared for Thursday’s workshop video. We’ll cover one of the new tools each week in detail. This week is the solder paste dispenser, followed by pick and place (hopefully), then reflow oven, hot plate, board preheater, and on down the production line.
Boards and stencils from Hackvana arrived just a few days after leaving the post office in Hong Kong. We’ll try that out and pop it into the reflow oven soon.
Had the US embassy add 48 pages to a couple passports. Crossing Hong Kong into China takes about 2 pages each time and there wasn’t room for a new Chinese visa for out Maker Faire trip to Shenzhen in April.
Speaking of Maker Faire China. Every flight was so expensive we ended up on Aeroflot, the Russian airline. It’s supposed to be quite improved, but we avoid it because Americans are stuck in the visa-free part of the airport if there is a cancellation or delay. To help compensate we’re grabbing 3 year multiple entry visas to Russia, just in case. This is not a fun process.
Work continues on Bus Pirate v4 menu selectable UART debugging mode. Today we hit a snag, as once the mode is activated communication seems to hang. We’ll revisit it tomorrow and try to debug the debugging mode.
UEFI secure booting has been on the minds of many hackers and open sources advocates. Some believe that it will lock out certain operating systems in favor of vendor’s proprietary systems. (There have even been recent reports of bricking Samsung laptops just by trying to boot Linux.)
In this video from last Summer’s DEFCON 20 conference, Dan Griffin, President of JW Secure, Inc., demonstrates trusted boot in action, and releases his Measured Boot Tool which allows you to view Trusted Platform Module (TPM) boot data and identify risks such as unsigned early-boot drivers.
Today we announce the winner of the NU-Xtal packages! These boards are quartz crystal and load capacitance breakouts, designed for breadboard prototyping by Mats. There were lots of great ideas, thanks for your submissions.
Congratulations to Kevin, his idea for a function generator scored him the NU-Xtal 20 Mhz package:
I have been thinking about making a function generator that is essentially the inverse of the Logic shrimp. Use a cheap micro to fill up serial SRAMs with whatever pattern is requested, then just continuously clock them to read out into an D2A converter.
Congratulations to Garrett, his idea for a ATMEGA1284 powered robot scored him the NU-Xtal 16 Mhz package:
That 16MHz crystal would also work very well on my new atmega1284 which will be going into robot making use of the frame of an old RC HUMMV (it had a rechargeable battery holder and the motors and wheels needed already together, so why not?)
And last but not least congratulations to Callen, his honesty gets him one NU-Xtal unpopulated PCB:
Well, nothing particularly… It’s for breadboarding, so I’d use it any time a breadboard was used and I needed it. I’ve got a lot of projects in the pot brewing and as my daughter gets older, I’m finding more time to work on them.
Thank you to Mats Engstrom for the free swag.
Thank you for participating, there were a bunch of great ideas. As always feel free to share your projects in the forum.
Nick designed re:load, a cheap 0-30A general purpose dummy load and posted it in the forum a few months ago. It’s got over-current, over-voltage, and over-temperature protection. While the circuit is similar to many other DIY dummy loads out there, the key to Nick’s safer solution is the usage of the BTS117 smart low side switch IC, which acts as a regular N-channel MOSFET, but has all of the above mentioned protection circuitry built in. This project is now available on Tindie.
Here’s another custom Li Ion battery charger and holder. Yesterday we ran a post involving a custom battery holder for cell phone batteries, today it’s a holder for a more conventional 18650 type Li Ion batteries.
To make a battery charger, just solder the red and black leads to the BATT+/- terminals on the charger board. I got this PCB on eBay for US $1.58 (£0.98). It can be powered by a mini USB cable and features a TP4056 chip which is a generic version of the LTC4056 Li ion charger chip.
We picked up some UltraFire brand Li Ion batteries in China. Seems like a poor name for a product that does have some reputation for sudden and intense explosions.
Via the comments.
Juanma built a USB IR Toy free PCB. With the USB IR Toy you can use a remote control with your computer, view infrared signals on a logic analyzer, capture and replay remote control buttons.
If you build a free PCB we’ll send you another one! Blog about it, post a picture on Flicker, whatever – we’ll send you a coupon code for the free PCB drawer.
Here’s how we mail free PCBs.
You can get IR Toy v2 for $22.05, including world wide shipping.
Via Twitter.
Today we worked on implementing the Bus Pirate v4 debugging mode, as a custom command you may enter even when connected over USB. This mode allows you to communicate with the Bus Pirate over UART in parallel to USB.
Every Tuesday we give away two coupons for the free PCB drawer via Twitter. This post was announced on Twitter, and in 24 hours we’ll send coupon codes to two random retweeters.
Don’t forget there’s free PCBs three times a every week:
Some stuff:
We try to stagger free PCB posts so every time zone has a chance to participate, but the best way to see it first is to subscribe to the RSS feed, follow us on Twitter, or like us on Facebook.
Mats has dazzled us with his board a week projects, and now one of them could be yours! Today Mats is giving away three NU-Xtal packages, a crystal breakout for breadboard prototyping. Each package has:
Leave a comment on this post with a project idea and this board could be yours!
We’ve been informed of the new MAKE publication by authors John Baichtal, Matthew Beckler and Adam Wolf entitled LEGO and Arduino Projects: Projects for extending Mingdstorms NXT with open-source electronics. The purpose of the book is to acquaint beginners with the both Mindstorms and the Arduino platform and how they can be interfaced using open source components through a number of example projects.
The book requires the Bricktronics shield created for this book by Open Source Hardware kit maker Wayne and Layne. The shield breaks out various Arduino pins into four sensor and two motor control connectors for the Mindstorm.
If you’re a LEGO enthusiast or know someone who is, you’ll want to check out LEGO and Arduino Projects, which lists for $34.99 (or less) on Amazon.
Via MAKE.
Free PCB builder extraordinaire Kenneth did an extensive teardown of an HP ProCurve 2824 Ethernet Switch. He analyzes the PCB piece by piece, explaining the smaller function blocks and how they fit together.
So that is how all of the internals of a 24 port managed switch interact with each other at the system level. The processor is surprisingly under-powered, but only handles clerical tasks with respect to switch configuration. The switch itself is a multi-layer tree consisting of physical transceivers, 1Gb switches linking 12 ports, and a 10Gb switching fabric back plane linking multiple switches.
Via Twitter.
An updated version of the QFP surface mount protoboard is now in the Seeed shop. This revision uses the Sick of Beige DP10080 standard. All footprints have been reworked and extended for easier hand soldering.
Sometimes we have the wrong size protoboard for a new chip. Now there’s a second 0.50mm footprint on the back side of the 0.80mm protoboard. That increases the chances it’ll fit whatever chip you’ve got.
You can get one for $10 at Seeed Studio.
