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StyloCard

Posted on Tuesday, May 8th, 2018 in PCBs, techniques by DP | 5 Comments

stylo6-600

Stylophone business card project from mitxela.com

Printed Circuit Boards as a business card are a great gimmick. I’d seen ones with USB ports etched into them, which enumerate as a keyboard and then type a person’s name or load up their website. It’s just about possible to build them cheap enough to hand out as a business card, at least if you’re picky about who you give them to.
A couple of years ago I took a stab at making one for myself, but I didn’t want it to be pointless. I wanted it to do something useful! Or at least entertain someone for longer than a few seconds. I can’t remember quite how I got the idea of making a MIDI-stylophone, but the idea was perfect.

More info at mitxela.com.

Check out the video after the break. (more…)

#FreePCB via Twitter to 2 random RTs

Posted on Tuesday, May 8th, 2018 in Free PCBs by DP | No Comments

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.

Raspberry Pi virtual floppy for ISA (PC XT/AT) computers

Posted on Monday, May 7th, 2018 in hacks by DP | No Comments

pi-isa-drive-board-600

Dr. Scott M. Baker wrote an article detailing how he turned a Raspberry Pi into a virtual storage device for ISA bus computers:

I’m tired of carrying compact flash cards and/or floppies back and forth to my XT computer. I like to do development at my desk using my modern windows PC. While I can certainly use a KVM switch to interact with the retro computer from my Windows desktop, it would be a lot more convenient if I could also have a shared filesystem. There are several alternatives, from serial port solutions, to network adapters. However, I wanted something that would emulate a simple disk device, like a floppy drive, something I could even boot off of, so I implemented a virtual floppy served from a Raspberry pi.

See the full post on his blog here.

Check out the video after the break. (more…)

LoRa module in DIL form

Posted on Monday, May 7th, 2018 in ARM, wireless by DP | No Comments

lora-breakout-600

Mare writes:

Murata produces LoRa module CMWX1ZZABZ-xxx based on SX1276 transceiver and STM32L072CZ microcontroller. The soldering of the LGA module is not very hobby-friendly. I constructed small breakout PCB for this module with additional buck/boost switcher and place for SMA connector. The transceiver features the LoRa®long-range modem, providing ultra-long-range spread spectrum communication and high interference immunity, minimizing current consumption. Since CMWX1ZZABZ-091 is an “open” module, it is possible to access all STM32L072 peripherals such as ADC, 16-bit timer, LP-UART, I2C, SPI and USB 2.0 FS (supporting BCD and LPM), which are not used internally by SX1276.

More details on Mare & Gal Electronics site. Project files are available at Github.

Free PCB Sunday: Pick your PCB

Posted on Sunday, May 6th, 2018 in Free PCBs by DP | 12 Comments

BP-600x373

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:

(more…)

App note: How to implement an SCR or a Triac in hybrid relay applications

Posted on Sunday, May 6th, 2018 in app notes by DP | No Comments

an_stm_DM00356324

Another app note from STMicroelectronics on SCR or Triac hybrid with mechanical relay to decrease power loss and manage inrush current. Link here (PDF)

This document gives some key information about the design of the solid-state silicon AC switch stage of a hybrid relay, which can drive resistive, capacitive or inductive AC loads, such as: heater resistors, motors for industry, power tools or appliance applications.

App note: AC switches – Is a positive power supply mandatory for my application, or could a negative output work also?

Posted on Sunday, May 6th, 2018 in app notes by DP | No Comments

an_stm_DM00128617

App note from STMicroelectronics about the usage of a negative supply in controlling AC switches and their benefits, Link here (PDF)

In this application note we explain the reasons why some appliance designers might choose a positive power supply. This selection is based mainly on the choice of switched mode power supply (SMPS). Some specific applications cases, may also lead to the choice of a positive power supply.

Using a power supply with a positive output is not convenient for all applications. For example, a negative supply is preferred to drive AC switches. We provide here an alternative solution which allows a negative output to be implemented whenever possible. Further, many solutions allow both a negative and a positive output (for the microcontroller) to be implemented.

ESP8266 SPI Spy

Posted on Friday, May 4th, 2018 in Arduino, wireless by DP | No Comments

pzem021_front-600

nop head writes:

I came across a very useful post by Thomas Scherrer that describes how to read data from a Peacefair PZEM-021 energy meter by spying on the SPI bus with an Arduino. I decided to do the same thing with an ESP-12F WiFi module so that I could view the results remotely and plot graphs, etc. It took me a lot longer to get this working than I anticipated due to a few problems along the way.
The main hardware difference is the ESP8266 is a 3.3V device but the Arduino is 5V. The PZEM-021 is actually a mixture. The RN8208G metering chip is a 5V device. It is a SPI slave, the SPI master is an STM32 ARM processor that is 3.3V but with 5V tolerant inputs.

More details at HydraRaptor blog.

Free PCB coupon via Facebook to 2 random commenters

Posted on Friday, May 4th, 2018 in Free PCBs by DP | No Comments

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:

(more…)

Desoldering station

Posted on Thursday, May 3rd, 2018 in hacks by DP | No Comments

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Stynus writes:

Some time ago I bought a lot of Weller soldering irons at an auction for cheap. Between these where a few DSX 80 de-soldering irons.
I also had an old Weller IG101 solder station (bought earlyer from another hobbyist), unfortunately I had no iron for this one and the DSX 80 could not be connected to this one. Time to convert the IG101 to newer standards.

More details at ElektronicaStynus homepage.

Check out the video after the break. (more…)

Stand-alone simulated analog meter

Posted on Thursday, May 3rd, 2018 in DIY, measurement by DP | No Comments

oled-vu-meter-600

DuWayne S blogged about his stand alone simulated analog meter project:

Thinking about what values I would like to display, I came up with three basic items.  A S-meter when in receive, and a power output display when in transmit.  In transmit, I would also like to have the capability of measuring VSWR.  Thinking about the switching functions required for this I will need one control line that monitors  transmit/receive, this can come from the PTT or key line in the transceiver.  Then  I use a second control line to select either power or VSWR when the T/R line is in transmit.  Another control line can do the same for the S-meter or some other display when in receive.  Since this is based on a VU meter, I will use that for the secondary function in receive.  Now looking at the signal lines I need to measure, they are the AGC line for S-meter, audio signal for VU meter.  And in transmit, the forward and reverse power levels will take care of power and a computed VSWR reading.

See the full post at DuWayne’s Place blog.

#FreePCB via Twitter to 2 random RTs

Posted on Tuesday, May 1st, 2018 in Free PCBs by DP | No Comments

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.

Attiny wearable

Posted on Monday, April 30th, 2018 in AVR, DIY by DP | 3 Comments

img_20180412_203153-600

Attiny wearable project from Facelesstech:

It’s a foundation for a wearable platform. It’s a Nato watch strap threaded through a PCB with a coin cell battery holder between the PCB and the strap. I’m using a Attiny85 this time around but could be used for most chips/dev boards. This is a proof of concept to iron out any problems I’ve overlooked.

Project info at Facelesstech’s blog and the GitHub repository here.

Check out the video after the break. (more…)

6 channel speaker selector

Posted on Monday, April 30th, 2018 in DIY, PIC by DP | No Comments

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Dilshan Jayakody published a new build:

If you are an audio enthusiast and if you have multiple audio systems and speakers, you may definitely need to have a speaker selector switch. These switches allow you to route a audio signal through a switching system and distribute it to various speakers. Using this listener can select single amplifier – speaker combination through the switch. We mainly design this switch to share our speaker system with multiple audio amplifiers. We design this switch to handle 6 stereo audio channels.

See the full post on his blog here.  Project files are available at Github.

Free PCB Sunday: Pick your PCB

Posted on Sunday, April 29th, 2018 in Free PCBs by DP | 11 Comments

BP-600x373

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:

(more…)

App note: Electrical techniques for using different power sources on vibration motors

Posted on Sunday, April 29th, 2018 in app notes by DP | No Comments

an_precisionmicrodrives_ab011

Application bulletin from Precisionmircodrives on powering vibration motors from different and some cases fluctuating power sources. Link here (PDF)

As vibration motors have a wide variety of applications, they are often integrated into systems which have different power sources. A common concern, in terms of power supply, is adjusting the source power supply voltage to a suitable level for the vibration motor or drive circuitry. This protects the motor, and can ensure a constant level of performance for uses like haptic feedback.

App note: Map colors of a CIE plot and color temperature using an RGB color sensor

Posted on Sunday, April 29th, 2018 in app notes by DP | No Comments

an_maxim_AN5410

An app note from MAXIM integrated on RGB color sensor and their capability to correct color deviation by providing feedback based on a reference color. Link here (PDF)

This application note will show how all the colors within the color gamut formed by red, green, and blue constants in a CIE plot can be measured and mapped with an RGB color sensor. This RGB sensor can also monitor the color output of LEDs in a display and/or provide feedback to maintain a reference color. An RGB sensor will also be mapped to measure the color temperature of practical light sources.

Free PCB coupon via Facebook to 2 random commenters

Posted on Friday, April 27th, 2018 in Free PCBs by DP | Comments Off on 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:

(more…)

Multisensor LoRa device

Posted on Thursday, April 26th, 2018 in sensors by DP | No Comments

p-tlmv2-600

Mare published a new build:

The described device is nearly matchbox-sized board (50 x 24 mm) packed with sensors. Auxilary board is 10x50mm with additional sensors. The module is developed around the Murata ABZ LoRa module, which integrates STM32L072 and samtech SX1276 in tiny 12.5 x 11.6 x 1.76 mm package.

More details at Mare & Gal Electronics.

DIY Moteino guide

Posted on Thursday, April 26th, 2018 in DIY, tutorials by DP | No Comments

p-image9-600

Felix writes, “I posted a short illustrated guide for making your own Moteino from SMD components. It also includes details how to burn the bootloader and fuses. Check it out here. Thanks and credit goes to forum user LukaQ for his contribution of the images and test sketches in this guide!

See the full post at LowPowerLab.

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