Category Archives: electronics

Time Delay Relay

I’m working on a project that requires two power strips to be turned on in a sequence. The first power strip powers 6 HDMI displays, and the second one powers 6 computers. The displays have to be on before the computers so they sync properly and get the correct resolution. Since I can’t rely on a person to do this properly, automation is the answer.

My first thought was to use something like a PowerSwitch Tail with a microcontroller to trigger it. (There’s also a cheaper kit version available.) The issue with this solution is that I’d need a microcontroller, and a power supply for the microcontroller, which are more parts, and more points of failure, and take up more space. I also considered using a cheap relay module, but ultimately I was overly complicating the whole thing. Also, I want this to be reliable, and sticking a 5v power supply, a microcontroller, and a relay in a box for three years seemed a little risky.

What I really needed was a “Time Delay Relay” which is a device that can get power, wait X number of seconds, and then power on another thing. There’s a whole bunch of them you can just buy! Time Delay Relays are not cheap though… This one is under $40, but you’ll probably also want the socket, which puts you closer to $50.

Luckily, Milwaukee Makerspace is filled with all sorts of old industrial “junk” and we have a bunch of these sitting on a shelf! Brant (you know, the guy who made a Auto-Off Timed Outlets from an old microwave control panel) helped me find one and get it wired up last week. It works great!

I used a $3 extension cord to provide an easy way to plug it into the first power strip and plug the second power strip into it. There’s a dial that lets you set the delay up to 10 seconds, which is more than enough for my needs.

Time Delay Relay

If I’ve learned anything from this project it’s that even though you think you might have a good solution to a problem, it’s still worth asking others (at the space or on the mailing list) because you may get a better solution, and may even get the parts you need.

Special Event–Calling All Audiophiles

Thursday, November 12, 2015 at Maui Makers 6 to 9 PM

200 Waiehu Beach Rd, Upstairs

Steve Griffin from Boeing has offered to preview his class on using the SigmaDSP board.

This class has several interesting aspects:

A group tutorial setting up a noise canceling system to eliminate background noise. This is similar to the system used in expensive noise canceling headphones. It can also be used to reduce noise in building ventilation systems.

The Sigma DSP board here. This cute little board is specially built for audio processing and can be used to optimize your soundscape and compensate for noise or limitations of your equipment and environment.

A tutorial on Sigma Studio, a graphical programming environment that is used to program this board. It can also be used to program SHARC processors.

Auto-Off Timed Outlets

If you’re like me, you’ve left a soldering iron plugged in once or twice.  Hopefully you’re also lucky like me and it’s never started a fire.   Occasionally I’ll grab something off our Hack Rack and take it apart.  A) It’s fun and B) it helps cut down on the ever-growing pile of appliances in the East Room.  Recently I focused my efforts on a microwave oven.  During my salvage operation I managed to extract one plastic fan, two thermal cutout switches, a transformer, the magnetron, a huge capacitor, and the controls.  I soon realized that what I had in front of me was a digital timer wired to a normally open relay.  I couldn’t immediately think of something to do with it, but it seemed too good to toss or disassemble further.  About a week later I decided to wire it to a pair of 120-volt receptacles.  Voila.  Any appliance with a standard plug can be set to run from 00:01 to 99:99 before powering off.  Just press “TIME COOK” then enter the time in minutes and seconds, then start.  The relay closes the circuit and the outlets are energized.  When the timer runs out, a piezo buzzes and the outlets shut off.  The relay on the microwave’s circuit board is 120-250 volt at 16 amps, so I’m fairly comfortable it will handle one or two 40-watt soldering irons.


Learn Arduino at Makers Local 256 Public Night!

This coming Tuesday (Nov 3) at 7:00 PM, we have some amazing people from coming by Makers Local 256 to give a presentation/demo/Q&A on Arduino microcontrollers and embedded electronics in general. They’re touring around the Southeast and ML256 is one of the many places they chose to stop by!

Their main objective is to talk to people about Arduino and what you can do with it. They’ll have some kits and parts available during and after the presentation, so if you don’t have an Arduino (or two) already, you can pick one up then. They’ll be showing off a neat display of a few different Arduino projects and circuits, so it should be interesting and fun!

They’ll be going through the entire process of designing, connecting, and coding up a simple Arduino project from start to finish. If you have any questions about your own project, they would love to discuss ideas and give help where they can.

There’s no cost to attend the presentation, but they will have parts available for sale if you need them. Anyone is welcome to attend!

El labo de viaje

Invitado por VIDEOSÓNICA, el labo se hizo presente en Cali durante la segunda semana de octubre para brindar una nueva edición del taller GAMELINES. Durante dos días y en dos sedes (el hermoso Lugar a dudas y la Alianza Colombo Francesa de Cali) construimos nuevos gamelines y compartimos el amor por la electrónica y los microcontroladores.

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Muchas gracias, Carolina Carvajal, Mariángela Aponte Núñez, Giovanny Terranova y todo el equipo de Videosónica por toda la hospitalidad y ayuda en la estancia en Cali!

Recuerden que Gamelines es hardware abierto. Acá encontrarán información sobre cómo programar el chip que se encuentra en el corazón de la placa.

El labo de viaje

Save the Environment and Learn a Skill!

We are wiring the E-lab and need your help Sunday, 14th of June 2015, noon-4pm!

Learn Something New

Learn how to attach the Ethernet connectors to cables to create a cable of arbitrary length. The tools and instructions are provided. The main requirement is that you not be colorblind, so you can identify the color-coded wires.

Save the Environment

We have some donated computers and other electronics that we need to get working. Help us test them and take them apart to salvage the useful parts, and then we’ll rebuild what we can and e-cycle what we cannot use (or do you have an up-cycling project in mind?).

These are good tasks to do while your waiting for adhesives to set, or 3D printed parts to be completed.



A year of Robot Club

One late winter evening, a group of a dozen men and women gathered around a couple tables in the cramped upstairs of a hackerspace. It was the inaugural meeting of the Robot Club, and there had already been some lobbying and promoting of projects. It was generally deemed that the group should work on related projects so as to help each other. The front runner, and first project undertaken was the quadcopter.

This was an ambitious undertaking. We wanted these to be able to carry a GoPro, which meant it would be heavier and more expensive than typical learner flight craft. Though we weren’t experienced enough to know this at the time… After a few mad weeks of research, we had a BOM (Bill Of Materials) of something that might, in theory, fly. Ravi provided some much needed expertise with robotics and RC. John and Matt pulled together the specs, hoping that the calculations for propellers, motors, and battery would be okay. Parts were ordered to build 10, and the waiting began…

But while we waited, we invited people in to demo various robots and help us learn what might be needed. Ali demoed a robot from a UW Engineering class that does maze solving using ultrasonic sensors and SLAM (Simultaneous Localization and Mapping). One of the primary challenges of robotics: dealing with uncertain data and the disparity between reality and the model.

Many thanks to Jim, who put together a CopterVm, and presented a lot of research around which FOSS software to use for flight control.

When the parts finally arrived, we were able to assemble and they were able to fly with surprisingly few tweaks. The first few flights were just up, hover for a while, then land. We didn’t really expect it to go well, so it was still impressive…

A year of Robot Club A year of Robot Club

After a few test flights, some UFO sightings were reported. ☺

A year of Robot Club

Many tweaks were simply hacks, like soldering the right battery connectors, which didn’t match. There were a lot of neat innovations stemming from the original project! Ryan demonstrated the importance of not flying indoors. Neil designed a shock absorbing landing gear. Jim outfitted his with remotely dimmable lights. Enrico built an emergency parachute.

A year of Robot Club A year of Robot Club

A year of Robot Club A year of Robot Club

We flashed SimonK onto the ESCs — taking care as we discovered that some of these were the newer models with inferior response time, so we had to wait for a new version that didn’t cause these to melt and fall from the sky. Kanoa replaced the frame with a more rugged one and mounted both a FPV (remote First Person View) and GoPro.

A year of Robot Club A year of Robot Club

After the summer, the projects diversifies a little for two reasons: we didn’t want to fly in the cold and dark, and others were coming out with their robots. Chris has been working on a balance bot. David has made some really cool muscle controlled actuators. Shaun hacked a RC car to turn it into a bot. There have been multi leg walkers and several other robots.

A year of Robot Club


The winter project was a tiny robot, which autonomously does challenges. We only got around to doing some line following, though looked into several other sensors too.

A year of Robot Club A year of Robot Club


Here’s an ESP8266 hooked up to 9 axis sensors (accelerometer, gyroscope, magnetometer) sending the information to ROS.

A year of Robot Club

We’ve learned a lot about a lot of tech. We’ve used Arduino, Teensy, RaspPi, ESP8266, and MultiWii. Sensors include accelerometer, gyroscope, magnetometer, GPS, IR reflectance sensor, ultrasonic rangefinder. We’ve used 3D printers and a laser cutter. Software includes: ArduPilot, Robot OS, OpenSCAD, Vagrant, APM Planner, MAVProxy, mavlink, Linux, OpenCV (Computer Vision). Hope to have more frequent updates going forward!

Lezing : Electronics in a harsh environment

Op dinsdag 17 februari 20:00 organiseert Chainlab ism TkkrLab een lezing over “Electronics in a harsh environment” door Andries Lohmeijer.

Andries is elektronica ontwerper in hart en nieren én eigenaar van KITT engineering. Na vele jaren en vele bijzondere projecten heeft hij ruime kennis opgebouwd over het toepassen van elektronica in ‘harsh environments’.

Andries zal twee lezingen geven over ‘elektronica in barre omstandigheden’. Want hoe ga je om met je pcb ontwerp als het geplaatst moet worden in een omgeving dat last heeft van EMC, Temperatures, Static Discharge, Humidity, Corrosion etc.?

In het tweede deel dat 4 maart bij FabLab Enschede plaatsvind  zal Andries tips en Trucks geven hoe je te wapenen tegen deze bedreigingen. Denk hierbij aan EMC Protection, Groundloops, gebruik van zwevende voedingen, shockresistants, bliksemafleiden etc.

Voor meer informatie zie onze wiki

Chibitronics Build Night This Thursday

Join us this Thursday, December 11th from 7:30-10pm, for the Chibitronics circuit stickers Build Night. This is a free event, and we’ll have the basic materials you’ll need, but feel free to bring any electronics you’d like to incorporate, or projects that could use sticker circuits. We have LEDs, effects packs, sensors, and even microcontroller stickers that you can reprogram (they use an ATtiny85).

If you want to get ahead of the game, check out the Chibitronics website for tutorial videos.

See you Thursday!

Chibitronics Build Night This Thursday

Video Wall of Terror

This weekend, I helped decorate for a Halloween Party at my sister’s house. There’s an odd hallway that connects their main large public room to the rest of the house. It’s used for storage, and has shelves on both sides.

This year, I decided to decorate that area by creating a video wall effect. Something like a Television Control Room of Terror!

To start with, I simply filmed my brother-in-law with a video camera – only from WAY TOO CLOSE! I shot macro video of his eye and mouth. Then I edited the footage to create a custom looping DVD.

In the hallway, I set up multiple monitors. These are old monochrome standard definition monitors that were on their way to the recycling center. They were professional monitors, which means that they can pass a video signal through from one monitor to another, making it easy to daisy chain several monitors.

Next to the monitors, I set up three DVD players (including one car DVD player – hey I use what I got!) to play the three different custom DVDs – Right Eye, Left Eye, and Mouth. Each of the three videos is a different length, so they will continue to drift out of sync. That way, as they loop, the visuals are a continuingly changing experience through the whole evening.

Above the monitors, I set up a video camera on a tripod and fed it to some of the monitors. That way, when party-goers look at the monitor, they also see themselves. Having feedback on some of the monitors adds a sense of interactivity to the project.

After the monitors and DVD players were all set up, I covered the rest of the shelving with black paper. In a dark hallway, lit only be black lights, it’s a great effect of creepy images floating in the hall.

If you want more details on this project, I made a full step-by-step write-up on Instructables.

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