DIY AD9833 signal generator

Daumemo has been working on a DIY signal generator based on an AD9833 IC:

In this post I am going to continue with the DIY signal generator based on the AD9833 IC where I have left in the previous part. Earlier, I have talked how I had built my first analog signal generator’s stage – variable gain amplification circuit. Usually, a generator needs to have an ability to change not only the signal’s amplitude, but also its offset. So, today I will walk you through a circuit which adds an offset to the DIY generator’s output signal.

More details on his blog. See part 1 of this series for the analog signal generator’s stage.

DIY AD9833 signal generator

Daumemo has been working on a DIY signal generator based on an AD9833 IC:

In this post I am going to continue with the DIY signal generator based on the AD9833 IC where I have left in the previous part. Earlier, I have talked how I had built my first analog signal generator’s stage – variable gain amplification circuit. Usually, a generator needs to have an ability to change not only the signal’s amplitude, but also its offset. So, today I will walk you through a circuit which adds an offset to the DIY generator’s output signal.

More details on his blog. See part 1 of this series for the analog signal generator’s stage.

Arduboy with removable flash cart

A homebrew Arduboy with removale flash cart from Facelesstech:

I’ll start with the Arduboy its self. I wanted to make a small Arduboy that anyone with basic soldering skills could make. I don’t think its the easies of boards to solder but its the only way I could make it small enough and have all the features I wanted. I just went with the standard SSH1106 0.96″ screen that most people use in their homemade builds. The buttons I went with are the ones I’ve been using on my other RetroPie builds in the past. They are soft touch but they are not mushy like some are and have a small foot print.

More details on Facelesstech homepage.

Check out the video after the break.

App note: FPGA power supply considerations

App note from Vishay Siliconix, giving us tips on powering FPGAs. Link here (PDF)

An FPGA is a device that offers many logic elements – up to 1 million gates in a single device at this writing – as well as other functionality such as transceivers, PLLs, and MAC units for complex processing. FPGAs are becoming very powerful, and the need to power the devices effectively is a key, if often underestimated, part of the design. A straightforward power supply design process can significantly reduce the number of required design iterations for the OEM designer.

DIY wireless temp/humid/pressure sensors for measuring vacuum sealed 3D printed filament containers

Scott M. Baker writes:

I made some wireless sensors, using BME280 temperature, humidity, and pressure sensors, together with SYN115 transmitter modules. I used these to verify the storage of vacuum sealed “PrintDry” 3D filament storage containers.

See the full post on his Scott M. Baker blog.

Check out the video after the break.

App note: Inductive switching for dual 24 and 36 V High-side switch families (XS4200 and XSD200)

Another app note from NXP describing the behavior of the SMARTMOS Dual 24 – 36 V high-side switch devices, at switch OFF when driving inductive loads. Link here (PDF)

These intelligent high-side switches are designed to be used in 24 V systems such as trucks and busses (XS4200). They can be used in industrial (XSD200) and 12 V applications as well. The low RDS(on) channels can control incandescent lamps, LEDs, solenoids, or DC motors. Control, device configuration, and diagnostics are performed through a 16-bit SPI interface, allowing easy
integration into existing applications.

App note: Repetitive short-circuit performances of the MC12XS6 IC’s family

App note from NXP about the short-citcuit protection strategies of their MC12XS6 centralized automotive lighting drivers family IC. Link here (PDF)

The MC12XS6 devices include up to five self-protected high-side switches, with its extended protection and diagnostics, to detect bulb outage and short-circuit fault conditions. Additionally, this device incorporates a pulse width modulation control module, to improve lamp lifetime with bulb power regulation at no less than 25 Hz, and address the dimming application (daytime running light).

Pogo pins + laser cutter = test fixture

Eric Gunnerson made this DIY pogo-pin test jig:

I decided to build a pogo-pin test jig, and since the approach I came up with was different than the other approaches I’ve seen I thought it would be worth sharing. I’m going to be targeting my laser cutter for fabrication, though I could have chosen to use my 3D printer instead.

See the full post on Eric’s Arcana and RiderX blog.

Check out the video after the break.

How to design and build your own Lithium battery pack

Adam Bender posted detailed instructions of how to design and build a custom DIY lithium battery pack with 18650 cells:

Designing a custom lithium battery pack is a fun way to learn about electricity and engineering. Lithium batteries can be used for countless applications including electric bikes, scooters, vehicles, backup power suppliers, off the grid solutions, and much more.

More details on Adam Bender’s blog. See part one of this series for the battery build.

Check out the video after the break.

App note: Orientations and Rotations

App note from Kionix on the introduction of most common method in determining orientation and rotations in an accelerometer. Link here (PDF)

The fact that accelerometers are sensitive to the gravitational force on the device allows them to be used to determine the attitude of the sensor with respect to the reference gravitational vector. This attitude determination is very useful in leveling or gimballing gyroscopes and magnetometers for use in compass and navigation instruments; determining tilt for game controller applications; and determining tilt or rotation for screen rotation of handheld devices. The method for calculating orientation or rotation depends on the specific application.