Lab LED constant current controller board

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Ladvien blogged about his Lab LED constant current controller board project he made using DirtyBoard PCBs:

A little lab controller PCB I’m working on. It centers around four high-power constant current circuits meant to be driven by an Atmega328’s PWM.
I hate working on anything mechanical in dim light; comes from dropping parts down under the engine when working on cars. I’m also pretty particular about my type of light. The “Cool White” or CFLs really bother me. I feel like I’m a bug headed towards a bug-zapper.

I have a few design goals,
1. Warm white is the way to go. I’m shooting for four 1k lumen warm-white LEDs at 12v at ~1A.
2. I’ve a plug for an Arduino Pro Mini (APM). It’s hard to fight the APM when it comes to small footprint and versatility, oh, and price. They are super cheap if you buy them on eBay.
3. I want to make a BLE serial interface using my HM-10. This would allow me to control my LEDs using my iOS devices.
4. The A4 and A5 pins are broken out, this is meant to make the boards chainable using I2C.

Check out the video after the break.

Continue reading “Lab LED constant current controller board”

Free PCB coupon via Facebook to 2 random commenters

BP

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 “Free PCB coupon via Facebook to 2 random commenters”

Replacement LED driver for AN6877

aflevelmeter

Dilshan Jayakody writes:

AN6877 is linear AF level meter IC produced by Panasonic and it is commonly found on many audio equipment. This chip is no longer manufactured by Panasonic and finding replacement chip for AN6877 is also quiet difficult.
The circuit described in this article is design to replace AN6877 base LED drivers and it is based on commonly available components. This replacement LED driver is design using 10, MMBT3904/2N3904 transistors and it can easily modify to get necessary number of outputs.

Project info at Jayakody’s blog and elect.wikispaces.com.

isoUSBRS422, an open source isolated USB-RS422/RS485 converter board

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Alper Yazar has posted an update on his open source isoUSBRS422 project we covered previously:

As I said, basically it is an USB ↔ RS-422/RS-485 converter board. It can be used to communicate devices with RS-422/RS-485 interface by using a USB port of PC. Also, ground of USB port is isolated from ground of RS-422/RS-485 channel. It may help you to prevent ground loops in large systems. If you are not sure whether you need isolation or not, probably you do not need it.

More info at Alper’s project page.

You can find the tutorial videos here.

Linting with Eclipse and the GNU ARM Embedded Launchpad compiler

lint-messages

Erich Styger of MCUonEclipse writes:

For a space project we have to make sure that things are not failing while our hardware orbits around the Mother Earth. Therefore we are using different static and dynamic analysis tools, and one of it is using PC-lint from Gimpel to catch as many errors and bugs as possible. For that project, we are using Eclipse with the GNU ARM Embedded (launchpad) ARM compiler and Eclipse as IDE with the GNU ARM Eclipse plugins. There are commercial plugins available for linting with Eclipse (e.g. Linticator), but with a few tweaks it is possible to lint with Eclipse free-of-charge. So this article is about how to lint an Eclipse project with PC-Lint.

More details at MCU on Eclipse site.

Looking inside a silicon die

electronupdate writes:

A very interesting branch of electrical engineering is the reverse engineering and analysis of silicon dies of semiconductors. The tools to play in this field are very specialized and I suspect very expensive.
In this video I went for the spend-no-money approach to see how far I could get at doing a top-side die polish of an integrated circuit. An arcane pursuit to be sure, but I was a bit pleased at how far I got using nothing more than some diamond paste and the equipment lying about in my workshop.

#FreePCB via Twitter to 2 random RTs

IRToy-600x369

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.

3D printed case for Bus Blaster v4

BusBlaster

dretay made a 3D-printed Bus Blaster v4 case:

A basic enclosure for the Dangerous Prototypes Bus Blaster v4. The enclosure needs to be the full height of the programmer due to the jumpers. In the future I may trim down the jumpers on my board and use a thinner case that exposes more of the JTAG header. I’ve included the 123Design source file in case you’d like to modify it further.

More cool DIY cases here.

Mini version of the OSI-300 trainer

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Here’s Christopher’s mini version of the OSI-300, he wrote a post on his blog detailing its assembly:

The OSI Model 300 Computer Trainer was advertised by Ohio Scientific Instruments in 1976 as a computer designed to introduce individuals to computers and teach them the basics of programming the MOS 6502 processor. The original trainer consists of a MOS 6502 processor, 6810 128 byte static RAM, one bit output latch, switches for entering data, and LEDs for reading the values of RAM.
The trainer was intended as a starter for individuals before moving on to their more advanced Model 400 Superboard system.

I first encountered one of these at VCFE 9.1 in 2014, and was intrigued by the simplicity of the design.  I was particularly interested in the operation, and wanted to learn how the switches and LEDs were interfaced to perform the data read/write operations.

Project info at Randomvariations.com

App note: Ceramic Varistors TNR™

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A technical note on varistors by Nippon Chemi-Con Corporation. Link here (PDF)

A varistor has the volt-ampere characteristics in which current suddenly starts to flow through the device at a certain voltage. Varistors are used to protect semiconductor devices in electronic and electric circuits from overvoltage. They are inserted in parallel with a circuit to be protected. When an impulse is applied to the circuit, pulse current flows to limit the pulse voltage to the varistor limit voltage Vclamp.

Free PCB Sunday: Pick your PCB

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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:

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App note: Conductive polymer aluminum solid capacitors

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Presenting the polymer capacitor by Nippon Chemi-Con Corporation. Link here (PDF)

Conductive polymer aluminum solid capacitors, which will be abbreviated to “polymer capacitors” in the following, have been recently extending in their applications. The polymer capacitors as well as conventional aluminum electrolytic capacitors are featured by large capacitance and excellent bias characteristics which multilayer ceramic capacitors can never compete with. In addition to these advantages that aluminum electrolytic capacitors have as well, the polymer capacitors have extremely low ESR characteristics. Regarding ESL, which it is determined by inside structure and terminal configuration of the capacitors, by making structural improvements the polymer capacitors have low ESL compared with the conventional aluminum electrolytic capacitors.

Also, concerning the dry-out of electrolyte in service life and the changes of characteristics at a range of low temperatures that have been regarded as disadvantages in aluminum electrolytic capacitors, the polymer capacitors have realized very high reliability and superior low temperature characteristics by using solid polymer materials as an electrolyte.

The polymer capacitors having these features have been demonstrating their capabilities in various fields. Their common uses are described in this application note.

Free PCB coupon via Facebook to 2 random commenters

BP

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 “Free PCB coupon via Facebook to 2 random commenters”

Souliss device ESP based combined with 3D Printing

MontadaTop

Juan has been working on a Souliss device ESP based project, that is available at Github:

With this board we can control 3 monocolor led strips (or 1 RGB), can host multiple sensors and options to come by external modules or internal conectors, Im working on this modules now. For now this board can host a LDR to meassure light on the room, temperature , humidity, pressure, pir, rain sensors… . It have an I2C and ICSP connectors, so we can connect Displays and others directly on the board.
Network settings can be configured via webinterface, and most important Slots can be configured too, you can see multiple options on my GITHUB.
Power is regulated from 12v to 3.3v. No heating problems.
It have 2 buttons, one for reset and other to enable program mode, can be used like a standard button too!

Project details at Juan’s Google Groups.

Arduino Mini CNC Plotter Machine from DVD drives

FXMZ39OIHP6TLUC.LARGE

An instructables on how to make an Arduino based mini CNC plotter from old DVD drives by Ardumotive_com:

For the X and Y axes we will use two stepper motors and rails from dvd/cd drives and for the Z axis we will use a small servo motor that moves the pen up and down. For the mounting base we will use a small piece of plexiglass.
You can easily attach a pen (or pencil) – irrespective of its thickness – on it. I tried to use an extension of cutting tool (e.g.Dremel) to engrave materials with no success. So this mini cnc can only be used as a small plotter and not as an engraver machine.
The Arduino-based circuit is using the ATmega328 microcontroller, two L293 motor driver ICs and an usb to serial module. You can easily make it with the Arduino uno board and an breadboard.

Check out the video after the break.

Continue reading “Arduino Mini CNC Plotter Machine from DVD drives”

#FreePCB via Twitter to 2 random RTs

IRToy-600x369

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.

Homebrew SWR and power meter

Meter0

Flathagen blogged about his DIY SWR meter project:

The circuit is based on two AD8307 log amplifiers, which are connected to the forward and reflected ports on a directional coupler. The AD8307 amplifiers gives a DC voltage of about 25mV/dB of the input signal, which is amplified using an opamp (LM324). The opamp also provides the reference voltage to the Arduino (AREF) to ensure that the full ranges of the A/D converters are used.
I used the fourth opamp in the quad LM324 to provide input voltage reading. That is why the PCB in the picture has two power jacks. One input and one output. That way I know the drive voltage for the radio. I primary plan to use this device for my Softrock.

Project info at Flathagen DIYycrap blog.

Enter the Photon

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Peter Scargill writes:

So, what differentiates this from say, something like an ESP-12 or similar boards? So this is a small WIFI-enabled controller, programmed in something that looks suspiciously like the Arduino language – this is course is deliberate to give it that familiar look and feel. But looks can be deceiving – this is a powerful ARM Cortex M3 processor with a Broadcom WIFI chip complete with on-board v3v3 power supply – oh and the design is open-source.
Pins include D0-D7, A0-A5, ADC, DAC and serial I/O an the unit supports battery operation. You get 1 MB Flash and 128KB RAM. There’s an RGB status LED (nice touch) and FreeRTOS is pre-installed. There is a softAP setup mode and the unit is FCC,CE and IC certified. There is an internal ceramic aerial and a connector for an external aerial. You also have SPI,I2C,I2S (whatever that is), CAN, USB and PWM.

More details at Pete’s blog.

App note: Start-up test using electronic load

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An app note from Alpha and Omega Semiconductor on importance of start-up power behavior to diagnose and prevent unwanted inrush current. Link here (PDF)

Electronic loads, such as Chroma 6310 series, can be configured as constant current (CC) mode, constant voltage (CV) mode and constant resistance (CR) mode. In CC mode, the load will sink a current in accordance with the programmed value regardless of input voltage. In CV mode, the load will sink current to control the voltage source in programmed value. In CR mode, the load sinks a current linearly proportional to the input voltage in accordance with the programmed resistance. Internal feedback control circuit controls the load current based on its mode set up and input voltage.