App note: L6234 three phase motor driver

in app notes by DP | 0 comments


An app note (PDF!) from STMicroelectronics on L6234 three phase motor driver:

The L6234 is a DMOSs triple half-bridge driver with input supply voltage up 52V and output current of 5A. It can be used in a very wide range of applications.
It has been realized in Multipower BCD60II technology which allows the combination of isolated DMOS transistors with CMOS and Bipolar circuits on the same chip. It is available in Power DIP 20 (16+2+2) and in Power SO 20 packages.
All the inputs are TTL/CMOS compatible and each half bridge can be driven by its own dedicated input and enable.
The DMOS structure has an intrinsic free wheeling body diode so the use of external diodes, which are necessary in the bipolar configuration, can be avoided. The DMOS structure allows a very low quiescent current of 6.5 mA typ. at Vs=42V , irrespective of the load.

ESP8266 Wifi information LCD

in project logs, wireless by DP | 0 comments


Renze shares his ESP8266 Wifi information LCD in the project log forum:

This is a little project I did in about 2 hours. It uses an LCD display I got from an old ISDN phone and shows text sent to it over WiFi.
The ESP8266 runs a webserver which shows a form that can be used to set the text. After the ESP8266 receives the text it sends the text to an Arduino using the serial port. The Arduino then shows the text on the lcd.
The biggest goal was to make the device as small as possible, by placing all the components directly on the lcd’s circuit board I managed to make the circuit only a couple of millimetres higher than the height of the clips of the lcd bezel.
(The display is an Optrex dmc50652n lcd)
If anyone is interrested in the source code of the esp8266 and arduino firmware please let me know.

Via the forum. Continue reading →

Free PCB coupon via Facebook to 2 random commenters

in Free PCBs by DP | 0 comments


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.  The coupon code usually go to Facebook ‘Other’ Messages Folder .  More PCBs via Twitter on Tuesday and the blog every Sunday. Don’t forget there’s free PCBs three times every week:

Continue reading →

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Hacking a LAMPAN Ikea lamp

in hacks by DP | 0 comments


Jesus Echavarria wrote an article detailing how he hacked the LAMPAN Ikea lamp:

The aim of this project, besides my own entertainment, is to have a lamp with the following features:

  • First, and obviously, maintain the connection for a light bulb, for the times that she wants to read before sleep.
  • Set manually the colour of the lamp on a easy way. This includes turn on the light bulb, change the colour or turn off the lamp.
  • Also, the colour can vary from a device with a bluetooth connection, such a mobile phone or tablet.
  • Set a timeout to turn off automatically the lamp.

Details at jechavarria’s project page.

Via the contact form.

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Make an ATTiny85 programmer and development board

in AVR, DIY by DP | 1 comment



Larry blogged about his DIY AVR ATTiny85  programmer and development board:

Starting from upper left is the 6-pin AVR programming header. I chose it because it has +5 and GND as well as the programming signals and can power the board. Next a red LED to show power to the board. Upper right is an LED tied to pin 4 for the default blink ‘hello world’ program. But with so few pins available, a jumper to disconnect the LED for pin 4 in case the application wants that pin. Below it is a reset switch.
Next across the bottom are headers, arduino like, bringing out each pin as well as an extra +5 and GND. There never seem to be enough. I also thought it could support a mini shield too.

Project info at Larry’s KB7KMO blog.

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Proof of concept: Open source ARM SWD debug and general purpose board

in ARM, open source by DP | 0 comments


Erich of MCUonEclipse writes:

The Freescale FRDM boards are using a Kinetis K20 based circuit (see “OpenSDA on the Freedom KL25Z Board“): However, that firmware is not open: the K20 is secured and protected, so the firmware cannot be changed. Newer Freescale FRDM boards like FRDM-K22F2 and FRDM-K64F do have an open source bootloader and debug firmware (see “DOC-100720“).
So: take a Freescale Kinetis K20 ARM Cortex-M4, the open source bootloader and firmware, shrink everything to the size of a Teensy board, add headers both to debug the K20 and an off-board microcontroller, and we have tiny board which can be used as a standalone versatile microcontroller board: usable for small projects or usable as debug probe.

Continue reading →

GPS based car locator

in Arduino by DP | 2 comments


A GPS based car locator by msuzuki777, an instructable here:

The GPS continuously reads the latitude and longitude of the CarTracker. When the button is pressed, the coordinates are saved to the EEPROM. E.g., this would be the location of your car. Now, let’s say you walk out of a store and are looking for your car. Power up the CarTracker. Do not push button. The GPS will read the coordinates of the store and will calculate distance and direction from there to the stored location (of the car). The compass will orient the display so the display will point to the car and will display the distance.

Via Embedded Lab.

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#FreePCB via Twitter to 2 random RTs

in Free PCBs by DP | 0 comments


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:

  • Hate Twitter and Facebook? Free PCB Sunday is the classic PCB giveaway. Catch it every Sunday, right here on the blog
  • Tweet-a-PCB Tuesday. Follow us and get boards in 144 characters or less
  • Facebook PCB Friday. Free PCBs will be your friend for the weekend

Some stuff:

  • Yes, we’ll mail it anywhere in the world!
  • Check out how we mail PCBs worldwide video.
  • We’ll contact you via Twitter with a coupon code for the PCB drawer.
  • Limit one PCB per address per month please.
  • Like everything else on this site, PCBs are offered without warranty.

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.

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Serial terminal view in Eclipse Luna

in how-to, software by DP | 0 comments


Erich  writes:

I’m using mostly an external terminal program like Termite. But it is a very useful thing to have a terminal view in Eclipse so I do not need to switch to another application. All what is needed is the installation of a plugin plus the RXTX (at least on Windows). And best of all: it comes with telnet, SSH and local shell too :-)

Step by step guide at MCU on Eclipse.

ChipHeadBang – design for an USB to Serial converter with ICSP header for (slow) bitbang programming

in AVR, USB by DP | 1 comment


microtherion has published new project the ChipHeadBang, that is available on Github:

Design for an USB to Serial converter with ICSP header for (slow) bitbang programming, based on the CH340G chip.

While this seems to work pretty well, and the CH340G can be obtained extremely cheaply from sources such as AliExpress, driver support can be a bit iffy. For current versions of OS X, the vendor provided driver will cause kernel panics, and as far as I know, only this commercial alternative will work

Posted in AVR, USB | Tagged , , , | 1 Comment

Free PCB Sunday: Pick your PCB

in Free PCBs by DP | 69 comments


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:

Continue reading →

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App note: Magnetic stripe reader

in app notes by DP | 2 comments


Application note(PDF) from Silicon Labs on Magnetic stripe reader (MSR) implementation.

Magnetic stripe readers (MSRs) are widely used in many different applications such as point-of-sale terminals and key card readers. The C8051F330 is capable of integrating MSR functionality in a very small space with few external components. The high-speed, high-resolution ADC, coupled with a fast controller core makes this integration possible. This design demonstrates a two-channel MSR function using the on-chip ADC to read information directly from the magnetic read head. Output can be viewed using a PC’s terminal program via an RS-232 connection.

App note: SMBus communication for small form factor device families

in app notes by DP | 0 comments


SMBus specifications and example implementation on Silabs’ C8051F3xx and C8051F41x. App note here(PDF)

This   application   note   describes   the   SMBus specification,  how  to  configure  and  use  the  on-chip SMBus  interface,  and  SMBus  debugging  techniques. Code  examples  written  in  C  provide  the  general framework  for  most  SM Bus  Master  and  Slave implementations. An example that interfaces to a 256-byte EEPROM over a two-wire interface and supports multi-byte transfers is also included at the end of this note.

App note: A Closed-loop, wideband, 100A active load

in app notes by DP | 5 comments


A closed-loop, wideband, 100A active load (PDF!) app note by Jim Williams of Linear Technology:

Digital systems, particularly microprocessors, furnish transient loads in the 100A range that a voltage regulator must service. Ideally, regulator output is invariant during a load transient. In practice, some variation is encountered and becomes problematic if allowable operating voltage tolerances are exceeded. 100A load steps, characteristic of microprocessors, exacerbate this issue, necessitating testing the regulator and associated components under such transient loading conditions. To meet this need, a closed-loop, 500kHz bandwidth, linearly responding, 100A capacity active load is described below.
Study of this approach is prefixed by a brief review of conventional test load types and noting their shortcomings1.

Audio oscillator with frequency counter

in DIY by DP | 0 comments


Xristost blogged about his DIY Audio oscillator with frequency counter project:

After I finished the oscillator, I made some minor changes in the square signal part of the schematic. I connected five of the inverters in parallel with low value load resistors, thus reducing the influence of the parasitic capacitance of the PCB. The goal is to lower rise and fall times of square signal. Max output voltage in square signal mode is around 5V.

Project info at Xristost’s DIYfan blog.

Free PCB coupon via Facebook to 2 random commenters

in Free PCBs by DP | 7 comments


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.  The coupon code usually go to Facebook ‘Other’ Messages Folder .  More PCBs via Twitter on Tuesday and the blog every Sunday. Don’t forget there’s free PCBs three times every week:

Continue reading →

Posted in Free PCBs | Tagged | 7 Comments

Week in (p)review April 17, 2015

in week in review by DP | 1 comment


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
  • Free PCBs via Twitter on Tuesday
  • Weekly roundup and preview every Friday
Posted in week in review | Tagged , | 1 Comment