Free PCB Sunday: Pick your PCB

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:

Continue reading “Free PCB Sunday: Pick your PCB”

App note: How to select an ambient light sensor for your end equipment

an_ti_sbea006

Another application note from Texas Instruments about ambient light sensors and how to effectively use them. Link here (PDF)

Generally, when someone thinks of trying to design a system with an ambient light sensor there are four main concerns or problems that need to be addressed. The most important features of an ambient light sensor are spectral response, power, size, and range of lux measurement.

App note: How to isolate signal and power in isolated CAN systems

an_ti_slla386

CAN system isolation app note from Texas Instruments, Link here (PDF)

With the increase in the usage of signal isolation in many industrial and automotive applications, the need for isolated power has also increased. The benefits of isolation are lost if the power supplies on either side of the isolation barrier are simply shorted. At the same time, if the isolated power sub-systems are not designed carefully, it affects the overall system performance like temperature rise due to poor power transfer efficiency, data corruption due to emissions, and so on. To simplify the design process of isolated CAN sub-systems, this document provides various options (discrete and integrated) to isolate CAN signals and power.

ESP32 and the CWTD ‘Test gadget’

esp32 test gadget

DuWayne published a new build:

I have been following a series of podcasts from ‘Chatting with the Designers’  CWTD.ORG that cover building simple Arduino based test equipment.  I decided that this would make a nice way to get into development with the ESP32.  The CWTD ‘Test Gadget’ is basically an Arduino Nano with a 2 line LCD display, and a breadboard area where small modules can be plugged in to make different types of instruments.  My version will use the ESP32 and the TFT display.  I am also replacing their rotary encoder with a joystick for the user interface device.  I am bringing all the pins from the ESP32 module out to two pairs of female headers, that should allow me to plug in two small modules at the same time.

See the full post on DuWayne’s Place blog.

Siglent SDG6000X Series Arbitrary waveform generator review, teardown and experiments

SDG6000X-300x149

A closer look at the newly released Siglent SDG6000X Series Arbitrary Waveform Generator from The Signal Path:

The full teardown of the unit reveals the internal architecture of the instrument, DAC / FPGA interconnect as well as the output amplifier structure. Although the limitations of the FPGA prevents the instrument to operate at full 2.5GSa/s in arb-mode, the instrument is capable of providing complex modulation up to the full 500MHz signal bandwidth.

More details on The Signal Path blog.

Check out the video after the break. Continue reading “Siglent SDG6000X Series Arbitrary waveform generator review, teardown and experiments”

Transistor radio series: the AF power amp

AF Power Amp

Vasily Ivanenko @ QRPHB writes, “I sought a low distortion, single supply, AF power amplifier for my transistor radios. I’ll present my experiments, some musings, test equipment and a reference to some wonderful books & their wise author. Sadly, some amateur radio receiver builders diligently craft their RF stages, but skimp on the PA audio stage. Actually — many commercial radio designers also do this.”

More details at QRP HomeBuilder blog.

Presenting the single ESC key USB keyboard

 

DSC00651_crop2 (1)

Glen Akins shares his latest build the single ESC key USB keyboard:

After building the “awesomely impractical” giant three-key keyboard, I decided it was time to build something a bit more practical—presenting the single ESC key USB keyboard! This keyboard has exactly one function which is to provide an optimal ESCing experience regardless of whatever keyboard you normally use. In exchange for giving up a USB port, you get a dedicated tactile, clicky Cherry MX blue ESC key.

See the full post on Photons, Electrons, and Dirt blog.

#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.

An easy way to mount DS18B20 temperature sensors

ds18b202-600

Matt wrote an article describing a technique he used to mount DS18B20 temperature sensors:

One of the biggest advantage of these sensors over I2C sensors, is that you can mount them almost anywhere. That having been said, I’ve never quite managed to come up with an elegant solution, particularly when attaching to a heatsink (for cooling applications)

More details at Matt’s Tech Pages.

 

 

Minimalistic 1D pong

m1dp-large

Here’s a minimalistic 1D Pong game from Vagrearg:

How little do you need for a game
An exercise in futility. That is what many would call this endeavor. How few elements (signifiers and affordances) do you need to not only recognize a game for what it is, but also are able to play it? The question applies whether you’re looking at a board game, a card table, or an online gambling Texas residents might pull up on a phone. It turns out that you only need very little to do very much.
It turns out that you only need very little to do very much.

Project info at vagrearg.org.

5 LDO regulator considerations other than voltage and current

Pryamiduino-R4-with-LDO-Regulator-Disabled-1600px-760x427

James Lewis over at Bald Engineer writes, “For an AddOhms series, I created a DIY Arduino I am calling the “Pyramiduino.” It is an ATmega328p based board in the shape of a triangle. Other than being cute, the shape does not offer any other benefit. The design features a 3.3 volt LDO Regulator, which is also the subject of this post.”

More details on Baldengineer’s tutorial page.

A journey into Capcom’s CPS2 silicon – part 3

cps2-battery

Eduardo Cruz published the third and last post in the Capcom CPS2 reverse engineering series we covered previously:

For many years, finding how and where did Capcom hid away its security implementation has been a pending critical task for the arcade community. CPS2 systems running out of battery were rendered useless forcing collectors worldwide to perform board conversions or let go of their favorite games.

See the full post on the Arcade Hacker blog. Be sure to see Part 1 and 2.

Free PCB Sunday: Pick your PCB

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:

Continue reading “Free PCB Sunday: Pick your PCB”

App note: Detecting selfie sticks using TI audio jack switches TS3A227E and TS3A225E

an_ti_scda014

Old app note from Texas Instruments on smart phone selfie sticks button detection. Link here (PDF)

Selfie sticks are becoming as common of a smart phone accessory as a pair of headphones. Because of the selfie stick’s increasing popularity, smart phone manufacturers need to be able to accommodate the accessory. This report describes the procedure required for a smart phone to detect when a selfie stick accessory is inserted into a smart phone’s audio jack receptacle using TI audio jack switches TS3A227E and TS3A225E. It shows how these devices respond to common selfie-stick implementations and how to adjust the audio jack switch’s register settings to accommodate both traditional audio accessories as well as the new selfie stick accessory.

App note: EMI-hardened operational amplifiers reduce inaccuracies

an_ti_sbot041

EMI reduction built-in on op amps, app note from Texas Instruments. Link here (PDF)

Operational amplifiers (op amps) with electromagnetic interference (EMI) filters can reduce significant errors. These types of errors are not always obvious to the system designers. They often impact the signal chain, in particular the analog-to-digital converter in the form of a loss of digital counts.

PI serial adaptor

p_20180527_114052-600

Raspberry pi serial adaptor from Facelesstech:

If you spend a lot of time building things with a raspberry pi you will eventually run into the problem that you have booted your pi it’s not plugged into a tv/monitor and it’s not connected to wifi. You don’t want to just turn it off because it could corrupt the sd card so what do you do. I recently ran into this problem but luckily I had a serial adaptor on hand to hook up and tell my pi to turn off.

See the full post on his blog and the GitHub repository here.

Check out the video after the break. Continue reading “PI serial adaptor”

ETA Nixie tube clock

ETA Nixie Tube Clock-600

Mark Smith over at surfncircuits has a nice write-up about building an ETA Nixie Tube Clock:

This DIY project will combine the estimated time of arrival function with a Nixie tube display to create an estimated time of arrival (ETA) Nixie tube clock. It is all easily controlled by a Raspberry Pi Zero W that is connected to the internet through WiFi to provide the latest time and gets the ETA for any number of destinations. The travel time is provided by the free Google Directions API interface that includes traffic to give the best estimates on any particular day.   The goal is that with an ETA Nixie tube clock, no math is needed to add a rough, often optimistic travel time, to the actual time to determine if we are running late.   The clock does that for you and with the power of IOT, is much more accurate!    A motion sensor is also added to the clock to turn off the Nixie Tube Display when no one is around, saving power and increasing the Nixie tube lifetime.

Build log at www.surfncircuits.com. Project files are located at Github.

CANable: the open source USB to CAN adapter

canable

An open-source USB to CAN adapter:

It supports CAN bit-rates of up to 1 Mbit/s. The product comes with an open-source SocketCAN driver software. It features a Micro-USB connector and a 4-pin screw terminal with CAN_H, CAN_L, 5-V supply, and ground. The CANable device is a hardware clone of Eric Evenchick’s CANtact project, an open-source USB-to-CAN hardware adapter

Via Open Electronics.

Arduino time attendance system with RFID

circuit-600

A how-to on building a time attendance system with MFRC522 RFID Reader and Arduino from Random Nerd Tutorials:

Before getting started it’s important to layout the project main features:
*It contains an RFID reader that reads RFID tags;
*Our setup has a real time clock module to keep track of time;
*When the RFID reader reads an RFID tag, it saves the current time and the UID of the tag in an SD card;
*The Arduino communicates with the SD card using an SD card module;
*You can set a check in time to compare if you are in time or late;
*If you are on time, a green LED lights up, if you are late, a red LED lights up;
*The system also has a buzzer that beeps when a tag is read.

More details at randomnerdtutorials.com.

Check out the video after the break. Continue reading “Arduino time attendance system with RFID”

#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.