Build a digital spirit level using SCA610 accelerometer


A spirit level is an “an instrument designed to indicate whether a surface is horizontal (level) or vertical (plumb).” Here’s a demo by Shawon Shahryiar of an electronic spirit level made using a Microchip PIC16F684, a SCA610 accelerometer and a handful of other discrete components.

Shawon writes, “This project used a one-axis accelerometer chip and therefore, the alignment can be measured in only one direction at a time. However, the concept can be extended for simultaneous measurements of orientation in two dimensions by adding one more SCA610 sensor or just choosing a dual axis accelerometer (like ADXL202).”

Project details as well as the schematic and source code link can be found in Shawon’s article at Embedded-Lab.

Week in (p)review: December 09, 2011

Here’s a summary of major developments over the last week:

Coming this week:

  • App notes on the weekend
  • Free PCB Sunday
  • Free PCBs via Twitter on Tuesday
  • New designs on Thursday
  • Free PCBs via Facebook on Friday
  • Weekly roundup and preview every Friday

What are you hacking this week?

App note: PSoC I2C to SPI bridge.

Here is an app note from Cypress that describes how to implement a I2C to SPI bridge on a PSoC IC.

PSoCs are devices that incorporate a microcontroller, a logical gate array, and some analog peripherals. What makes them different than microcontrollers is that all the peripherals are separated from the microcontroller. They can function totally independent from one another.

This app note describes how to connect two digital peripherals without sacrificing any additional resources of the IC.

PSoC is configured as an I2C slave and SPI master. This is because it can receive data from an I2C master and send this data to an SPI slave device. Also, the data received over the MISO line is stored so that it can be read by the I2C master during the next I2C read.

Make Tokyo Meeting 07 roundup

Make Tokyo Meeting 07 roundup:

Itead mystery gift arrives

Several weeks ago we posted about an X-Mas giveaway from Iteadstudio. We were surprised to see that it arrived during our stay in Tokyo! As it was shipped like a regular letter, we suspect it blasted past bigger parcels and slipped through quite easily.

If you’re still waiting for it, and don’t want to know what’s inside, don’t read further.

Continue reading “Itead mystery gift arrives”

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

You can get a Bus Blaster v2 for $34.95

Continue reading “Free PCB Sunday: Pick your PCB”

App note: Single battery boost converter

Here is an app note from Microchip that describes how to built a single battery boost converter. It provides a way to power higher voltage circuits with a lower voltage battery.

The design is based around the MCP1640 IC. It is a 350mA 500Khz boost converter with an integrated switch. Due to it’s design the device requires very few external components to function. One Inductor, two capacitors, and two resistors are all that is needed.

The efficiency ranges from 60% to 90% depending on the load and input voltage. Check out the graph below.

Continue reading “App note: Single battery boost converter”

Nicolas Collins’ original hardware hacking manual


If you want to read an irreverent and unorthodox hardware hacking manual check out Nicolas Collins’ Original Hacking Manual. Weighing in at 128 PDF pages, this book is geared toward motivating beginning electronics experimenters to explore uses and abuses for common electronic components. Topics include basic electronics through integrated circuits and circuit bending of all varieties. It is a manual he wrote and self-published in 2004 for his hacking course and first workshops that eventually became his book Handmade Electronic Music, as published by Routledge. Nicolas writes: “This version includes my terrible drawings, rendered obsolete by Simon Lonergan’s beautiful contributions to the Routledge editions, but perversely missed by some veterans of the early workshops.”

It’s replete with “rules” designed to keep the nascent hacker out of (too much) trouble. It is one of several interesting works made available courtesy of Nicolas Collins’ website.

App note: Dual 1.4MHz buck regulator with USB ‘Dying Gasp’ support

This app note from Maxim describes how to build a USB powered circuit that will provide a short power-failure notice before losing power. This is called the “Dying Gasp” and it allows devices to preform a proper shut-down when USB power fails.

A safe USB “dying gasp” shutdown requires a local energy storage capacitor to power the device and prolong operation for orderly shutdown. A circuit for a 5V USB “dying gasp” application provides a power-fail output warning time of 2.88ms.

The circuit described uses a 4.7mF capacitor to store energy for this prolonged shut-down. USB specification instructs that the input capacitance of any usb device must not exceed 10uF or have a inrush current greater then 100mA. This is upheld by limiting the charge current of the large capacitor with a resistor.

Once USB power fails the capacitor continues to power the circuit and discharge. When the charge drops below a threshold level the MAX1970 IC pulls the PFO pin high. This shuts off the input MOSFET Q1 and provides a warning to devices powered by the MAX1970 IC.


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:

  • Free PCB Sunday. The classic. Every week, get free PCBs right here on the blog comments
  • 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

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

Little Wire – minimal AVR programmer and more

The Little Wire is an open source AVR programmer that’s packed full of features:

  • An AVR programer
  • Four digital GPIO pins
  • ADC with 10 bit resolution
  • Two parallel hardware PWM outputs
  • An USB interface
  • A SPI interface

It is built to be DIY friendly by using all through hole components. It is also an open source hardware project, and different versions are already popping up in the forum.

Via the forum.

Digi-Comp II: vintage mechanical computing device


Digi-Comp was a fully functional binary digital mechanical computer, which sparked many future engineers’ imagination in the early 1960’s. The crew at Evil Mad Science recently revived the game with a larger than life version displayed at several Maker Faires. It uses billiard balls on a 4′ x 8′ deck to simulate electrical pulses moving through switches and flip-flops.

They will be introducing the Digi-Comp II kit soon. Click here for details.

Via Jameco.

Akihabara Electric Town tour roundup

Akihabara Electric Town tour roundup:

Driving Nixie tubes

In the second article about his Nixie tube clock Luca shows how to drive Nixie tubes with a microcontroller. The first article covered the power supply, we covered it here.

Nixie tubes are started with a high initial voltage Vigh, around 150-180volts. Once ignited they work at a maintaining voltage Vm, and consume a average current Ik. To drive them you need a current limiting resistor and a high voltage power source that is equal to their Vigh.

The resistor is calculated by the formula R = (Vign -Vm) / Ik, and the power dissipated by the resistor is calculated by P =  (Vign – Vm) * Ik.

Once a resistor is selected the rest of the circuit surmises down to controlling the ground of the tube with a NPN transistor, or a open collector output IC. You can check out his circuit in action in the video below.

Continue reading “Driving Nixie tubes”

Soldering iron driver update

Arhi continues to develop the universal soldering iron driver. This is a rendering of the third generation PCB.

The soldering iron driver can use soldering pencils with K-type or PTC type temperature sensors like Solomon, Hakko, and Weller, to name a few…

Generation 3 has a reworked analog section. It that now fully supports PTC type irons. A few more buttons are added, as well as a temperature probe to help with temperature control tuning.

We are impressed with his design, and can’t wait to build our version to experiment with.

Via the forum.

Bus Pirate PIC programmer through-hole version

MickM decided to rework our PIC programing adapter to a through-hole version. He made two versions of the board. One for both Bus Pirate V2go and V3, and one that supports only V3.

I got very confused reading the schematic, and had to redraw it.
One thing led to another and I laid it out as PTH.

Two versions, pin head jumper for V2GO/V3, and V3 only.
(all CC-by-SA of course)

Via the forum.

Bus Pirate v3.5 free PCB build

NBitWonder made a blog entry about his free Bus Pirate v3.5 PCB build. He used our simple mouser shopping cart to get the parts.

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.

Get your own handy Bus Pirate for $30, including world-wide shipping. Also available from our friendly distributors.