Radio thermostat CT-50 review and install

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Felix of LowPowerLab writes:

I mentioned before that there’s added support for HTTP requests in the gateway interface. That allows using things like wi-fi thermostats, and this story is a review of how I did just that.
I wanted to integrate the home thermostat into the Moteino IOT Framework Gateway and be able to control the thermostat remotely without hacking into it, building my own thermostat which would not look as good as a commercial one. I also want to avoid using the default cloud interface that comes with these thermostats. I don’t want the company to know my habits and datamine and profit from that, and also I want the thermostat to be integrated with my existing automation interface without having yet another app on my phone just for the thermostat.

More details at LowPowerLab site.

Check out the video after the break. Continue reading “Radio thermostat CT-50 review and install”

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”

Automatic 18650 Analyzer

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Gregor wrote an instructable detailing the build of his Automatic 18650 Analyzer project:

The idea behind this project was to create a cost effective device that could automatically charge and discharge multiple 18650 cells while determining the effective capacity of each individual cell. Individual cells can be binned by capacity, so multiple parallel packs with identical capacity can be put in series.
This Instructable will outline my complete design process including, specification development, component selection, circuit design/pcb layout, assembly, and software.

 

DPA library for MCU

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Ondřej Karas writes:

A few months ago, I published post about DPA .NET Class. This article describes simple, but effective library used for DPA handling by MCU (UART interface). Published library is independent on the MCU family, but it was written for 32-bit ARM processors with Cortex-M3 core and GNU C compiler.
Library consists of two files:

*header file: iqrf_dpa.h
*code file: iqrf_dpa.c

More details at DoItWireless.

Logic Sniffer in a 33.6Kbps modem case

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Peter Murray blogged about his Logic Sniffer case made from a 33.6Kbps modem box:

I have had my Open Workbench Logic Sniffer for quite a while and I have found it to be a very useful piece of kit. I have recently ordered an expansion to upgrade it to a 32 channel logic analyzer (up from 16), the little case which I put it in is going to be too small, so I have decided to put it into a bigger case.
I also have decided that I should create a front panel for this case because one issue that has always bugged me with the OWLS is that when you have unused channels, they seem to pick up “ghost” signals from the other lines. To remedy this I have put DIP switches on the panel which allow you to ground individual channels.

Project info at 39k.ca site.

There’s more DIY cases here.

Get a Logic Sniffer for $50, with free worldwide shipping.

#FreePCB via Twitter to 2 random RTs

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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.

Building a SmartWatch part 1

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Benjamin Blundell has been working on his DIY smart-watch:

I have an issue with smart-watches. Watches in general fall into one of two categories: a tool to tell the time, or a fashion statement. Increasingly, I believe the latter category is larger than the first. With the advent of the iWatch, Pebble and the like, fashion and making a statement has moved into technology. It’s not quite a new thing but nevertheless, it’s something I’m not too fond of. My solution? Make your own smartwatch.
There is a precedent for this. Steve Wozniack sports a pretty fly nixie tube watch which he made himself. It’s pretty cool, but also a statement of sorts too. I’ve been meaning to up my game with electronics anyway, so I’ve been working on a few initial prototypes.

Project info at Benjamin’s blog.

Continuous Autofocus laser cutter hack

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Continuous Autofocus of a laser cutter using a wiimote controller from Martin Raynsford, he writes:

We were inspired by the Glowforge laser cutters ability to continuously autofocus it’s z axis. A camera mounted in the head of the laser detects a laser dot being shone onto the surface of the material and from there it can determine how far the lens needs to be adjusted to set the focal height for the correct cutting distance.
The Nintendo Wii Remote has an optical camera in it that is used to detect up to four points of infrared light. The hardware automatically identifies these points and feeds back XY positions through a bluetooth connection. The cutting laser on a laser cutter is an infrared beam, as it cuts through the surface of the material there is a moment where it is reflected off the material and the Wiimote is able to detect the location of the cut. The location data is fed back to a laptop and by comparing this point against the initial ‘in focus’ point we’re able to detect if the Z axis needs to move up or down and by how much. The laptop sends data to an arduino that is connected between the laser cutters onboard Leetro controller and the Z axis stepper motor driver. The Arduino controller is the same as we have used on previous projects to control the Z axis. The result is a laser cutter that has the ability to remain in focus throughout the duration of a cut.

Project info at Raynsford’s blog.

Check out the video after the break. Continue reading “Continuous Autofocus laser cutter hack”

MCP2221 HID Library

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Zak Kemble writes, “This is a library for interfacing with the HID features of the MCP2221 USB to UART and I2C/SMBus serial converter from Microchip. The converter includes 4 GPIO pins, 3x 10-bit ADCs, 1x 5-bit DAC and more.
Microchip does provide a library for interfacing with the chip, however it is supplied as proprietary DLLs. This project aims to be an open-source and multi-platform alternative.
This library also makes use of HIDAPI.”

More details at Zak’s blog.

App note: Designing P.C. Board heat sinks

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Application hint from Micrel on how to do baseline calculation on board area required as heatsink for SMD components. Link here (PDF)

System designers increasingly face the restriction of using all surface-mounted components in their new designs; even including the power components. Through-hole components can dissipate excess heat with clip-on or bolt-on heat sinks keeping things cool. Surface mounted components do not have this flexibility and rely on the conductive traces or pads on the printed circuit board for heat transfer. This hint addresses the question “How much PC board pad area does my design require?”

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:

Continue reading “Free PCB Sunday: Pick your PCB”

App note: Heatsink characteristics

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Application note from International Rectifier on various method for thermal management. Link here (PDF)

In many electronic applications, temperature becomes an important factor when designing a system. Switching and conduction losses can heat up the silicon of the device above its maximum Junction Temperature (Tjmax) and cause performance failure, breakdown and worst case, fire. Therefore the temperature of the device must be calculated not to exceed the Tjmax. To design a good Thermal Management solution, the Tj should always be kept at the lowest operating temperature.

App note: Welcoming water metering into the 21st Century

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Maxim application note:

Water. It is the most precious managed resource on the planet. Getting clean water to everyone can, in fact, be a matter of life and death. Managing water resources is a serious challenge today. Water is expensive to clean and difficult to get to where it is needed. In fact, connecting people to clean water is one of the great challenges of the 21st century.
With so much at stake, the Internet of Things (IoT) and smart utility grids have an opportunity to improve the world by deploying accurate, reliable water flow-measurement technology. Utilities need to understand and monitor how water is consumed so they can estimate water requirements, but their water meters today do not do a good job of helping us find waste. Given the increasingly scarcity of water resources, we all need to know where every drop of clean water is going. In short, we need a network of ubiquitous, smart water meters.

Designing a CPU in VHDL

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A detailed guide on designing a CPU in VHDL by Domipheus:

This is part of a series of posts detailing the steps and learning undertaken to design and implement a CPU in VHDL. Previous parts are available here, and I’d recommend they are read before continuing.
Part 10 was supposed to be a very big part, with a special surprise of TPU working with a cool peripheral device, but that work is still ongoing. It’s taking a long time to do, mostly due to being busy myself over the past few weeks. However, in this update, I’ll look at bringing interrupts to TPU, as well as fixing an issue with the embedded ram that was causing bloating of the synthesized design.

Check out the previous parts at Domipheus Labs.

 

Understanding silicon circuits: inside the ubiquitous 741 op amp

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Ken Shirriff’s writes, “The 741 op amp is one of the most famous and popular ICs with hundreds of millions sold since its invention in 1968 by famous IC designer Dave Fullagar. In this article, I look at the silicon die for the 741, discuss how it works, and explain how circuits are built from silicon.”

Details at Ken’s blog.

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”

EDC/Krohn-Hite MV216A DC voltage standard teardown and Tempco measurement

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Kerry Wong did a teardown of the Electronic Development Corporation’s (acquired by Krohn-Hite) MV216A battery/external powred DC voltage standard:

In this blog post, we are going to take a look at Electronic Development Corporation’s (EDC, acquired by Krohn-Hite in 1998) MV216A battery/external powered DC voltage standard and also measure its voltage reference’s temperature coefficient (tempco). A teardown video is also included towards the end. MV216A is a six decade precision DC voltage standard, it can output from 0.1µV in 100mV range all the way up to 11.1111V in 10V range. Voltage standards of this caliber are usually used as calibrators to calibrate multimeters and other test instruments.

More details at Kerry Wong’s blog.

Check out the video after the break. Continue reading “EDC/Krohn-Hite MV216A DC voltage standard teardown and Tempco measurement”

48V Phantom power supply

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Dilshan Jayakody has designed and built a 48V Phantom power supply:

Phantom power supply is widely used in audio industry to power the active microphones over single audio cable. Most of the phantom power supplies deliver 48V DC over the balanced audio link and power supply unit described in this article is also based on same technique.
Phantom power supply in this article is based on TL783 high voltage regulator IC and 230V – 50V step down transformer. Like most of the phantom power supplies this power supply is also design to connect in between active microphone and audio mixer devices.

Project info at  Dilshan Jayakody’s blog.

 

Open Badge: The LED Badge

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Rohit Gupta published a new build, the OpenBadge

The major elements on the PCB were:
– LED Matrix
– A MSP430G2553 microcontroller brain
– A ULN2803 Darlington Driver to sink the current
– A USB connector to charge the battery
– A SBW connector to program the MSP430
– A Switch to change the message
– A Li-Ion battery from a Discarded Phone
– Current limiting and Pull up resistors
– Decoupling Capacitors
– A REG1117 Regulator for MSP430

Project details at Rohit’s blog.

Check out the video after the break. Continue reading “Open Badge: The LED Badge”

#FreePCB via Twitter to 2 random RTs

KHOS-2-3-4-5-6P 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.