3D printed circuitry

3D printed circuit

Rhys Jones has been working on 3D printing circuits using a RepRap printer.  He has recently made enough progress to have a working circuit.

One of the main problems I previously had was solubility. Running molten metals were acting as solvents for my heated nozzle – resulting in the nozzle slowly dissolving during a print. At the end of my last post I’d just tried using anodising to create a strong oxide layer on the surface of an aluminium nozzle to protect it, and that the results were promising after little running – I’ve done hundreds of hours printing since and as far as I can tell no damage has been done and its still in its original condition.

Here is a stab at the Arduino compatible Sanguino board (albeit simplified). It’s pretty standard except we’ve removed the reset circuitry and alot of the pins. We still have 4 controllable pins, one for the LED and three spare for something fun in future. Once again the plastic was printed before dropping in pre-tinned components and finally printing the metal tracks.

While this method of making circuits is unlikely to be cheaper than other methods of circuit fabrication it offers some interesting opportunities not found in other methods.  These include complex multi-layer circuits with components embedded arbitrarily at any layer.

Propeller object: solar position calculator and almanac


Here’s a unique Propeller code object providing the functionality of a Solar Position Calculator & Almanac. Written in Spin by Prophead100, this object takes input including date, local/solar time, latitude, longitude and daylight savings time status, and calculates “a good approximation of the position (altitude and azimuth) of the sun at any time (local clock or solar) during the day as well as events such as solar noon, sunrise, sunset, twilight (astronomical, nautical, civil), and day length. Derived values such as the equation of time, time meridians, hour angle, day of the year and declination are also provided.” This could be useful in designing a solar tracking system.

A demo program is included in the download and the heavy commenting is welcome, making these complex calculations easier to follow.

Via the Propeller Object Exchange.

Free PCB Sunday: Pick your PCB

We go through a lot of prototype PCBs, and end up with lots of extras that we’ll never use. Every Sunday we give away a few PCBs from one of our past or future projects, or a related prototype. Our PCBs are made through Seeed Studio’s Fusion board service.

This week two random commenters will get a coupon code for the free PCB drawer tomorrow morning. Pick your own PCB.

You get unlimited free PCBs now – finish one and we’ll send you another!

Don’t forget there’s free PCBs three times every week:

  • Tweet-a-PCB Tuesday. Follow us and get boards in 144 characters or less
  • Facebook PCB Friday. Free PCBs while you wait for the weekend
  • Free PCB Sunday, right here on the blog

Continue reading “Free PCB Sunday: Pick your PCB”

App note: Add high voltage capability to current sense monitors

Here is an app note from Maxim describing how to add high voltage capability up to 300V for the MAX47X (which have been replaced by MAX407X)  bidirectional current sense monitors. Since the MAX47X draw low current, a simple floating power supply can be used to power the device even at 300V.

The circuit of Figure 1 shows a simple way to add high voltage capability to the basic MAX471/2. Low supply current of the current monitor (100µA) allows a very simple floating power supply formed by avalanche diode D1, C1, C2, and the NPN current source Q1 and Q2. The voltage compliance of the current source provides the high voltage capability. With the part shown, Motorola MPSA42 (Q1), 300V is the maximum recommended, giving an absolute maximum input voltage rating for the whole circuit of 305.1V. Use of a 33V avalanche diode for D1 pushes this to 333V.

App note: Using UART Auto-Baud detection on dsPIC30 digital signal processors

Here is a app note from Microchip describing how to implement the Auto-Baud detection for UART operation on dsPIC30 digital signal processors. This function is useful when the oscillator of the dsPIC is unknown and/or the baud rate is unknown.

All current dsPIC30F devices have a UART peripheral with Auto Baud capability. The signal on the UART receive pin (RX pin) can be internally routed to an Input Capture module to time the edges of the incoming signal. From that timing the software can set up the UART at the correct baud rate. Auto Baud is useful when the baud rate of the incoming data is unknown and when the oscillator frequency of the processor is unknown. RC oscillators are often inaccurate and drift over time so systems with RC oscillators are ideal candidates for using Auto Baud.

Wireless dual DC motor control system


Chris from PyroElectro writes:

Here’s an article that explains how to build a dual DC motor control system, combined with a wireless receiver and transmitter (XBee modules) which tell the motors at what speed they should move forward, or backward. Standard and widely available parts are used so that anyone can follow along.

The system uses a PIC 18LF4520, LM317 variable voltage regulator, 1mW XBee modules, 3v or 6v DC motors, SN754410NE Motor Controller IC, 2N2222 NPN Transistor and a handful of discrete components. The article contains links to the schematics for receiver and transmitter and source code for the PICs.

Via the contact form.

Another PIC18F2550 USB development board

Palma made a USB development board for the PIC18F2550. These chips are really popular, and there is a bunch of projects floating around the internet with them, even our own USB IR Toy, and USB LCD Backpack use them.

This board is basically a breakout board, with decoupling capacitors, and a USB jack. We like that all the broken-out pins are connected two 2 pins of the dual row female header, making it easier to connect one pin to a more then one external component.

You can also check out our PIC18F2550 Breakout Board, build in the “blade” style, having all the breakout pins on one side of the board.

Bus Pirate helps out a hybrid race car build

A few days ago we were asked to help out a college team building a Formula Hybrid race car. They wanted to use the Bus Pirate to debug their electrical control system. We were happy to send one over.

Hi Ian,

I just wanted to say thank you again for the Bus Pirate. I finally had some free time to attempt to figure out how the battery management systems works and the Bus Pirate is a wonderful help. I will be sure to send you more pictures when the chassis for the car is complete (hopefully it will be this weekend).

Anyways, thank you again!
Nathaniel Quillin

Formula Hybrid cars are based on the Formula SAE challenge. The hybrid is propelled by a 200cc petrol engine, or a 300cc diesel engine, coupled with an electric motor. Batteries which help acceleration, and recharge under braking.

We wish them the best in their championship.

Hackerspace Global Grid asks for your help

As a response to SOPA, Nick Farr decided that it is time that hackers create their own communication network for the community and by the community. Shackspace jumped on board and started designing a satellite ground station network. They published their works on the project wiki page and listed tasks that you can help with if you want to help the project.

Open Source Hardware Association announced

Open Source Hardware Association Announced!

Open Source Hardware Association.

The Open Source Hardware Association is Coming Soon! It will be a non-profit organization (status pending) working to spread the love of open source hardware. We’re working out details, and as soon as we know, you’ll know! Check back at oshwa.org for upcoming news.

And here’s a note from Windell, one of the OSHWA board members.

OSHWA’s first project is a survey, “to better understand the Open Source Hardware community.” Catarina Mota has lead this project and created a survey along with David Mellis and John De Cristofaro. The aggregate and anonymous results will be made publicly available in May. If you’re involved with the OSHW community, we’d invite you to take the survey.

Exciting news and another milestone for open-source hardware!

Via Make.

Printf style debugging over AVR-ISP pins

ihsan kehribar from the Little Wire project informs us of his recent work entitled “Printf style debugging over AVR-ISP pins.” He writes, “if you are breadboarding an AVR chip, you are already using the SPI pins for programming the device; therefore it would be nice to use that cable for low-level debugging also. I wrote an Arduino library for that purpose and it is working! That means, you can set up an Arduino on a breadboard and use the Little Wire as programmer and also console interface for printf style debugging! But, you should tie down the SS pin to the ground as well.”

Via the contact form.

Free PCB coupon via Facebook to 2 random commenters


Every Friday we give away some extra PCBs via Facebook. This post was announced on Facebook, and on Monday we’ll send coupon codes to two random commenters. More PCBs via Twitter on Tuesday and the blog every Sunday.

Don’t forget there’s free PCBs three times a every week:

Continue reading “Free PCB coupon via Facebook to 2 random commenters”

HOW-TO: Single member LLC/Sole proprietor taxes

Here’s a dirty subject many new kit makers don’t think about until the last minute: paying taxes. If you’ve sold your first kits or hardware you’ve got a lot of record keeping and paperwork to do. Here’s a rundown of how we’ve done our US taxes for the last few years, but we’re by no means experts!

Where Labs, LLC is the Iowa-based business side of Dangerous Prototypes. In tax year 2011 it was fully owned by one person. By default the IRS classifies a single member LLC as a pass-through entity. That means the IRS doesn’t tax the business at all. Income and expenses are listed on the owner’s personal income taxes.

We’re not tax professionals, so you need to do the research yourself. Our strategy is to be completely honest, do our best, and maintain exquisite records. We assume that if we don’t hide anything the IRS will help us work out any problems. That said, here’s the barebones of how we do taxes for a single member LLC.

Continue reading “HOW-TO: Single member LLC/Sole proprietor taxes”

Week in (p)review April 13, 2012

Here’s a summary of major developments over the last week. Free PCB Friday is coming up soon:

Coming up:

  • Free PCBs via Facebook on Friday
  • App notes on the weekend
  • Free PCB Sunday
  • New 3D model on Monday
  • Free PCBs via Twitter on Tuesday
  • Weekly roundup and preview every Friday

What are you hacking this week?

Using the STM32W-RFCKIT 2.4 GHz development board to sniff 802.15.4 traffic via Linux

Joe designed a 802.15.4 network analyzer for Linux with the STM32W-RFCKIT , by reverse engineering the Windows only closed-source application note AN3406.

Summary: The STM32W-RFCKIT together with application note AN3406 is a nice low cost solution for diagnosing problems on a 802.15.4 (ZigBee, MiWi etc) network. Unfortunately the solution is Windows only and closed source. In this article I have reverse engineered the firmware protocol so that a similar solution can be implemented in Linux, Mac OSX and other platforms. I’ve also written a first draft of this software for Linux.

Via the comments.

Online vintage tech library

tubebooks.org – Vintage info from the age of vacuum tubes

tubebooks.org 

Vintage info from the days of vacuum tubes

Kelvin informs us of an online stash of vintage engineering docs at tubebooks.org. He especially recommends you check out the technical books section/link.

Tubebooks is “a collection of vintage engineering texts, vacuum tube datasheets, and other obsolete information, presented free of charge and without annoying advertisements.”

Via the contact form.

ZPUino v1.0 released

ZPUino is a system-on-chip 32bit microprocessor FPGA core, that functions with a modified Arduino IDE. All the files regarding the core are open-source and downloadable from their site, and so is the modified Arduino IDE.

Yes, that is true.
ZPUino 1.0 is now available for you to use and enjoy.
Expect some updates on next few days – release cycles are about to change, we’re switching to release early, release often.
As always, direct any questions to zpuino@alvie.com.

WORKSHOP VIDEO #14: Global Geek Tour China preview

We toured the prime geek locations in Hong Kong and Shenzhen, China on our penultimate Global Geek Tour. Monday thru Friday of next week we’ll have videos, pictures, and giveaways. Here’s a quick preview. Don’t miss a single day or giveaway next week.