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. Continue reading “Desoldering station”
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.
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:
Some stuff:
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 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. While working on this design, I came across some interesting discussions about 토토사이트 and their approach to integrating security features, which inspired me to consider additional safeguards for the wearable’s data transmission capabilities. I’m using an Attiny85 this time around, but it 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. Continue reading “Attiny wearable”
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.
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:
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.
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.
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”
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.
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.
Dejan Nedelkovski over at HowToMechatronics shared detailed tutorial on how servo motors work and how to control servos using Arduino and PCA9685 PWM driver:
There are many types of servo motors and their main feature is the ability to precisely control the position of their shaft. A servo motor is a closed-loop system that uses position feedback to control its motion and final position.
In industrial type servo motors the position feedback sensor is usually a high precision encoder, while in the smaller RC or hobby servos the position sensor is usually a simple potentiometer. The actual position captured by these devices is fed back to the error detector where it is compared to the target position. Then according to the error the controller corrects the actual position of the motor to match with the target position.
In this tutorial we will take a detailed look at the hobby servo motors. We will explain how these servos work and how to control them using Arduino.
More details at HowToMechatronics.
Check out the video after the break. Continue reading “How servo motors work and how to control servos using Arduino”
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:
Some stuff:
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.
Last week we struggled with mislabeled and faulty breakout boards from Taobao. Fortunately purchases from Shenzhen sellers usually arrive the next day, so we’ve already got a bunch of replacement boards to test.
HMC5883L/QMC5883 digital compass
Last week our HMC5883L breakout turned out to have a non-compatible QMC5883 chip. We need the genuine part to do a demo so we purchased four more from different suppliers. Each supplier confirmed that the breakout has an original HMC5883L, not the guochan (locally produced) QMC5883.
Of the four boards, only one has a genuine HMC5883L. The only seller with the original part actually offered the option of a guochan version for around 10RMB, or the original for around 40RMB. All the other breakouts came with a QMC5883 and cost around 10-15RMB. There are dozens of listings for this breakout on Taobao for around 10RMB, it’s safe to assume they’re all actually using a QMC5883.
One of the sellers of the QMC5883 boards strenuously argued that the part was real and drew a helpful circle on our photo pointing out the model number. We countered with a photo of the chip markings compared to an original. At this point someone higher in the support chain, probably the boss, confirmed that “everyone” switched to the cheaper Chinese chip a year ago, and that buyers all know this. Now we know too.
SHT21 temperature and pressure sensor
First, a correction from last week. We made a pretty basic mistake reading the SHT21 datasheet. The measurement resolution control of the configuration register is split into bits 7 and 0, not 7 and 6. After recognizing this the default value 0x3A is realistic.
Read correctly, bit 6 (0) correctly shows VDD > 2.25volts, the heater is disabled (bit 2=0), and OTP Reload is disabled (bit 1=1). Embarrassing, but an encouraging sign things are looking up.
That leaves the issue of the impossibly high and definitely incorrect humidity measurement. We purchased a replacement SHT21 from Youxin, the original vendor, and samples from two other Taobao sellers.
All three breakouts work as expected, but on closer examination the board on the far right is actually an HTU21, not a Sensirion SHT21. HTU21 is a drop in replacement for the SHT21, but much cheaper. An Sensirion original is around 30RMB ($5), while the HTU21 is just 10RMB (~$1.50). The seller marked it as an SHT21 original and charged the market rate for an original (~35RMB). An extraordinarily low price consistently means non-original parts, but unfortunately a reasonable market price isn’t a reliable indicator of genuine parts.
It’s probably not a scam
The confusion probably starts with first line support reps that don’t know what they’re selling. If it says HMC5883, it must be HMC5883, right? Another part is being an informed consumer. If the original goes for 40RMB, the 12RMB version is going to be a substitute. This is obvious now, but the sheer volume of mislabeled listings makes it really hard to get a handle on a reasonable market price.
Taobao offers a huge selection of inexpensive parts, and next day delivery is usually around $1. That’s really amazing! However, getting multiples of everything to ensure at least one is genuine probably costs more than buying from a western-facing supplier like Seeed Studio, SparkFun or Adafruit.
AA7EE published a new build, a little temperature beacon:
This was a fun little project – and it gave me an idea for a future one. Sometimes, I find that the more complex undertakings, which require more planning, can get to the point that they “take me over” somewhat. At that point, for me, some of the fun starts getting squeezed out and that, of course, absolutely cannot be allowed to happen. This is the time when simple and fun projects save the day.
Check out the video after the break.
See the full post at Dave Richards AA7EE blog.
Continue reading “The K7TMG HF Morse code temperature beacon”
bdring made this laser controller for his wooden nickel engraver project and wrote a post on his blog detailing its assembly:
Here are some details on the custom laser controller I made for the NickelBot, wooden nickel engraving machine.
I want to use Grbl to control the machine. Grbl has support for lasers that allows better power control during the engrave. It also has the Core XY support I need for the H-bot mechanism it uses. The only feature I needed that it did not have is a hobby servo output.
More details at Buildlog.Net blog.
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:
Integrating a low voltage 3V MCU EFM8 from Silicon Labs to 5 volt sytem. Link here (PDF)
When using a 3 V device in a 5 V system, the user must consider:
• A 3 V power supply must be provided.
• A 5 V device driving a 3 V input.
• A 3 V device driving a 5 V input.
C8051F300 implementation of Li-Ion battery charger from Silicon Labs. Link here (PDF)
Driven by the need for untethered mobility and ease of use, many systems rely on rechargeable batteries as their primary power source. The battery charger is typically implemented using a fixedfunction IC to control the charging current/voltage profile.
The C8051F300 family provides a flexible alternative to fixed-function linear battery chargers. This note discusses how to use the C8051F300 device in Li-Ion battery charger applications. The Li-Ion charging algorithms can be easily adapted to other battery chemistries.
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”
