Mostly PIC16C57


CAPS0ff team posted an article taking a closer look at 8 “PIC16C57s”:

We were recently sent 8 “PIC16C57s” from:

*High Seas Havoc (403/C013)
*Wargods (U69, C020)
*MACE (U96, C021)
*Carnevil (U96, C022)
*BioFreaks (C023)
*Gauntlet Dark Legacy (C024)
*Gauntlet (U37, C025)
*Blitz 99 (U96, C026)

More details at CAPS0ff blog.

6 channel speaker selector


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.

Building a giant USB three key mechanical keyboard


Glen Akins shares his latest build the giant three key USB keyboard:

After seeing this giant mechanical keyboard at Adafruit, I decided I had to build my own. Adafruit made theirs out of wood and used one of their Python-compatible microcontroller boards. I wanted a sloped top on my keyboard. I also wanted to check out what was new with Microchip’s USB device stack. I decided to build my keyboard out of aluminum and use a PIC18 microcontroller.

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

PIC18 four-channel DMX relay controller


Glen Akins has a nice build log on his four channel DMX-controlled relay, that is available on GitHub:

 Halloween was right around the corner and I needed a timer with a bunch of relays to trigger some store-bought props and a fog machine periodically. (Mental note: read fog machine specs carefully—not all come with timer remotes.) My first thought was an Arduino and cheap relay board. Second thought was to build something with a micro and some relays. Third thought was that if I’m going to build something, might as well add DMX and package it up into a neat enclosure. Hence, the four channel DMX-controlled relay project was born.

See the full post on his blog.

PICKit 3 Mini


Reviahh has published a new build, the PICKit 3 Mini:

Previously, I made a Pickit 3 clone – (see previous blog post). It works well, but I have often wondered just how little of its circuitry was needed to program and debug the boards I make. For instance – I primarily use the newer 3.3V PIC32 processors, so I really don’t need the ability to alter the voltage like the standard Pickit 3 can. I also have no real need for programming on the go, or even to provide power to the target MCU to program. Knowing this – I decided to see what I could do to remove the circuitry I didn’t need, yet still have a functioning programmer/debugger.

See the full post at DIY PCB homepage.

RX/TX sequencer


Lukas Fässler has designed and built an RX/TX sequencer based on a PIC16F18325,  that is available on github:

Much like the beacon keyer presented here earlier, this RX/TX sequencer is a simple but useful little device. Its typical use is in ham radio applications when a separate power amplifier (PA) and/or a sensitive low-noise pre-amplifier (LNA) is used. Care has then to be take to safely transition between RX and TX states – and that’s where this sequencer comes in.

Project info at Soldernerd homepage.

Check out the video after the break.

Beacon Keyer


Lukas Fässler from Soldernerd published a project writeup showing how he built a PIC-based beacon keyer:

This is likely the first ham radio related project that I document here on this blog
But my very first PIC project was a beacon keyer that I made for my father, HB9BBD. That was in 2013. A beacon keyer is a great project to get started with microcontrollers since it’s not much more than a fancy way of blinking an LED.

Project info at Soldernerd homepage and the GitHub repository here.

Light Dimmer Shows How to Steal Power from AC Line

We see a lot of traffic on the tips line with projects that cover old ground but do so in an instructive way, giving us insight into the basics of electronics. Sure, commercial versions of this IR-controlled light dimmer have been available for decades. But seeing how one works might just help you design your Next Big Thing.

Like many electronic controls, the previous version of this hack required a connection to a neutral in addition to the hot. This version of the circuit relies on passing a small current through the light bulb the dimmer controls to avoid that extra connection. This design limits application to resistive loads like incandescent bulbs. But it’s still a cool circuit, and [Muris] goes into great detail explaining how it works.

We think the neatest bit is the power supply that actually shorts itself out to turn on the load. A PIC controls a triac connected across the supply by monitoring power line zero-crossing. The PIC controls dimming by delaying the time the triac fires, which trims the peaks off of the AC waveform. The PIC is powered by a large capacitor while the triac is conducting, preventing it from resetting until the circuit can start stealing power again. Pretty clever stuff, and a nice PCB design to boot.

Given the pace of technological and cultural change, it might be that [Muris]’ dimmer is already largely obsolete since it won’t work with CFLs or LEDs. But we can see other applications for non-switched mode transformerless power supplies. And then again, we reported on [Muris]’s original dimmer back in 2009, so the basic design has staying power.

Filed under: home hacks, misc hacks

Christmas Lights Done the Hard Way

It’s that time of the year again when you gotta start worrying if you’ve been naughty enough to not receive any gifts. Hopefully, Blinky Lights will appease St. Nick. Grab a strip of RGB LEDs, hook them up to an Arduino and a Power supply, slap on some code, and Bob’s your Uncle. But if you want to retain your hacker cred, you best do it the hard way. Which is what [roddersblog] did while building his Christmas Starburst LED Stars this year — and bonus points for being early to the party.

christmas-lights-the-hard-wayFor starters, he got panels (as in PCB panels) of WS2812 boards from eBay. The advantage is it lets you choose your own pitch and strand length. The flip side is, you need to de-panel each board, mount it in a jig, and then solder three lengths of hook up wire to each LED. He planned for an eight sided star with ten LED’s each. And he built three of them. So the wiring was, substantial, to say the least. And he had to deal with silicone sealant that refused to cure and harden. But nothing that some grit and determination couldn’t fix.

For control, he choose the PIC16F1509 microcontroller. This family has a feature that PIC calls the “Configurable Logic Cell” and this Application Note describes how to use CLC to interface the PIC to a WS2811. He noticed processing delays due to C code overheads that caused him some grief. After some experimentation, he re-wrote the entire program in assembly which produced satisfactory results. You can check out his code on the GitHub repository.

Also well worth a look, he’s got a few tricks up his sleeve to improve the quality of his home-brew PCB’s. He’s built his own UV exposure unit with timer, which is an interesting project in itself. The layout is designed in Eagle, with a flood fill to minimize the amount of copper required to be etched away. He takes a laser print of the layout, applies vegetable oil to the paper to make it more translucent to UV, and doubles up the prints to get a nice contrast.

Once the sensitized board has been exposed in the UV unit, he uses a weak but fresh and warm solution of Sodium Hydroxide as a developer to remove the unexposed UV photo-resist. To etch the board, he uses standard Feric Chloride solution, which is kept warm using an aquarium heater, while an aquarium air-pump is used to agitate the solution. He also describes how he fabricates double sided boards using the same technique. The end result is quite satisfying – check out the video after the break.

Filed under: led hacks, Microcontrollers

Bitbanging VGA Fits In under 1 kB

Don’t throw those old VGA monitors away, turn them into works of art with [danjovic] and VGA Blinking Lights. This circuit uses a PIC16F688 to generate VGA video. Not just a random spray of monochrome dots either. VGA Blinking Lights puts up an ever-changing display of 48 colored squares.

blink-thumbOriginally created for the square inch contest, VGA Blinking Lights could hide behind a quarter. [Danjovic] dusted his project off and entered it in The 1 kB Challenge. The code is written in PIC assembly. The final hex used to generate the squares clocks in at 471 words. Since the PIC uses a 14 bit word, that’s just over 824 bytes. Plenty of space for feature creep!

Video is generated with a twist on the R2R DAC. [Danjovic] tweaked the resistor values a bit to obtain the correct voltage levels for the VGA standard. The color of the squares themselves are random, generated using a Galois Linear Feedback Shift Register (LFSR).

With only a handful of components, and a BOM cost under $5, this would be a fun evening project for any hardware hacker.


If you have a cool project in mind, there is still plenty of time to enter the 1 kB Challenge! Deadline is January 5, so check it out and fire up your assemblers!

Filed under: video hacks