Author Archives: DP

A self-expanding ESP32 PWM board

via Dangerous Prototypes

Eric Gunnerson writes:

I’ve been working on a little ESP32 expansion board/shield for an LED project I’ve been working on. One of the nice things about the ESP32 is that it has a peripheral known as “LED control” that provides 16 independent channels of PWM for controlling LED brightness, and my project uses that capability.
One of my projects is going to require all 16 channels, so I wanted to do a board that would support 16 channels, but I also wanted a version of the board that would only support 8 channels.

Project info at Eric’s Arcana and RiderX site. It’s also up on Tindie.

Check out the video after the break.

App note: Emitters and detectors for infrared (IR) touchscreens

via Dangerous Prototypes

App note from OSRAM about IR LEDs and IR detectors used on touchscreen technologies. Link here (PDF)

Touchscreens as a popular user interface are more and more common. Applications span from public information systems to customer self-service terminals. Thus, as a logical step, more and more devices today feature this kind of user interface, e.g. bank automatic teller machines (ATMs), personal digital assistants (PDAs), mobile phones and PC displays. The widespread popularity is actively supported by standard computer based operating systems, such as e.g. Windows® 7.

The rapid development of CMOS imaging sensors and the development of high power infrared (IR) emitters in slim packages have led to a series of new optical touchscreen technologies. Many of them contain proprietary technology and solutions.

Sequence controller

via Dangerous Prototypes

Eric Gunnerson has been working on a sequence controller project:

Yeah. Those pins are beautifully aligned a very precise 0.1” from where they are supposed to be…
Pro tip: Print out your design and put your components on it so that you can check the design.
Meta pro tip: Follow your pro tips.
Anyway, that’s not the only problem; it turns out that the power and LED parts of the connector are right underneath the end of the board, so you can’t use a normal header on them (you could use a right-angle one if you wanted), so I did a new revision of the board with 1.0” rather than 1.1” for the ESP and extended the board so the connectors are out on the end. That’s on the slow ship from China right now.

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

DIY AD9833 signal generator

via Dangerous Prototypes

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

via Dangerous Prototypes

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

via Dangerous Prototypes

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.