Category Archives: electric

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.

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.


$5 Upcycled Desk Clock

Last summer I came across a collection of car parts at a garage sale; instrument clusters, lights, gauges, and some digital clock displays.  For $5, I became the proud owner of a JECO Japan, vacuum fluorescent clock display.  The plastic housing held all the clock electronics, membrane buttons for setting the time, and a four-pin connector.  After powering it up, I realized one of the pins could be used to dim the display, which is a pretty nice feature to have.

I’ve worked on it off and on for a few months, but finally decided to finish it this weekend.  On Saturday, I tweaked some dimensions and laser-cut the final enclosure.  I wasn’t happy with the button holes and text I had on the front of the first iteration, so I got rid of them for the final.  You can adjust the time by slipping a jeweler’s screwdriver or a paper clip through a gap in between the plexiglass sides and pressing the buttons to add hours or minutes. 
$5 Upcycled Desk Clock
I added a small single-pole, double-throw toggle to switch between bright and dim, then soldered the connections before closing it up.  The whole thing is clamped together by a single #10-32 machine screw and a wingnut.  The final result doesn’t look half bad.
$5 Upcycled Desk Clock

Electric Ice Scooter


When I recently was at the thrift store and saw a pair of ice skates next to a kick-scooter, it got my mind going. “What would a scooter look like with skates in place of wheels!?”

The next time I was at the Makerspace, I saw my old electric scooter over on the Hack Rack. This was a scooter I originally rescued from a dumpster. Although it didn’t have batteries, just adding power and a little tinkering got it up and running again. A few of the EV Club and PowerWheels Racing guys played around with the scooter a bit, but eventually the controller got toasted, and who knows what happened to the front wheel.

Oh well, I’d be replacing that front wheel with an ice skate anyways.

Turns out that the heel of an ice skate is actually sturdy enough to drill right through and use as a mounting point. I simply  drilled through the skate, inserted a spacer, and then ran a 3/8″ bolt through the skate and the front fork of the scooter. I finished it off with a couple of washers and a nut.

Then next thing to fix was to get the  motor going again. Turns out that it’s a brushless motor. While I have a fair amount of experience now with BRUSHED motors, this was my first experience with brushless. I did a little research, and then ordered a 24V, 250 watt generic brushless controller from a mail-order scooter parts company. Unfortunately, it used a different style of throttle than what was already on the scooter, so I had to order a throttle to match.

Connecting the controller was pretty easy, three wires to the motor and the black and red one to power. I first bench-tested it with an old printer power supply, and once everything was working right, bit the bullet and bought a brand new pair of 12ah SLA batteries. The two batteries are wired in series, along with a 20 amp fuse, and then go to the controller.

I still needed a deck for the scooter. I dug through some scrap materials and found a pair of cabinet doors that were about the right size. I cut them down just a bit and bolted them to the scooter. I even re-mounted a cabinet door handle to have as an attachment point for towing a sled.

With that, I was ready to go for a test ride, so it was off to the lake. Once I was on the ice, I turned on the scooter and gave it a go! What fun! It really zipped along, but it was almost impossible to steer, as the back tire would slip right out from under me! Time for more traction!

I decided to make a spiked tire. I removed the rear wheel, then disassembled the two-part rim and removed the tire and inner tube. I stuck 1/2″ self-tapping, pan-head, sheet-metal screws through the tire from the inside, so that their points stuck out.DSC_0394 I evenly spaced out 24 screws and alternated them to be slightly off-center side to side. Next, I put some old scrap bicycle inner tube over them as a liner to protect the scooter tire inner-tube. After that, it was just a matter of reassembling everything.

Now for test #2 out  on the ice. Remembering how much it hurt to fall on the ice, I was prepared this time by wearing my motorcycle jacket (which has padding built-in) and my helmet. Good thing too, as I would learn while steering with one hand and holding a GoPro camera in the other…. (Note to self, keep both hands on handlebars at all times.)

Overall, the Ice Scooter works great! I still have a few little things to do on it. For example, the motor is running “sensor less”, and I’d like to learn about how brushless motors use the sensor system. I’d also like to get a small 24V dedicated charger. As it is right now, I have to remove the deck and manually charge with a little 12V charger.

From thrift store idea, to hack rack, to life on the ice, it’s always fun to see what you can do with just a little ingenuity. I hope you like this project. If you want to see more on it, please check out the write-up I did on Instructables. It’s even in a few contests there, and I’d love your vote!

Keep on Making,


Lighting Control Upgrade!

IMAG3517In an effort to make the lighting control system more user-friendly, the original board-mounted switches have been replaced with a laser-cut zone map! Instead of looking up which zone number corresponds to a particular bank of lights, each location is now identified by a green LED pushbutton.  You can read more about the lighting control system and how it’s been evolving on our wiki:

Red Lotus Repairs (Part II)

Power Wheels Repair

We made some good progress last time, but the repairs continue, and this time we got as far as a test drive!

We managed to finish the motor mount, get the chain on, repair the kill switch, and fix a wobbly wheel. We still need to get the new brakes in place, reattach the cooling fan, and see about some replacement wheels. But yes, it is running!

If all goes well we should have it ready by Minne-Faire on April 13th, 2013 in Minneapolis, Minnesota. (We decided not to drive it there, but instead will put it in the back of a regular old gasoline-powered vehicle, just so the batteries are fresh when we get there. :)


Check the video (which is a time lapse of the repairs) and you’ll see a few shots of driving it (note to self: take camera out of time lapse mode when driving!) There’s also a short bit of real-time video at the end showing a first-time guest driver taking it for a spin. (Literally!)

Red Lotus Repairs

Red Lotus Repairs

Tom and I spent some time this past weekend repairing Red Lotus, our #55 Power Wheels Car. Working with Tom is great because I end up learning a ton of new skills, like how to use an angle grinder, and the mill, and some welding tricks. These will all come in handy when the car breaks (and it will break) in the middle of a race.

Besides fixing up the car, we’ve also been building up the team, and it looks like at least two of us will try to make it to Minne-Faire in April for a bit of pre-season racing fun.

Here’s a quick time lapse video of Tom and I doing some repairs.

February Electric Car Club

Electric Car Club

Did you know that we’ve got a number of members who have built electric cars? Ben Nelson even runs and has published DVDs and Instructables showing you how to build your own. (Sharing of knowledge is a top priority for our members!)

If you’re interested in electric cars, come on down to Milwaukee Makerspace at 1pm on Sunday, February 10th, 2013 for the first Milwaukee Electric Car Club Meeting at our new location. Got a Tesla, or a Volt, or some DIY/converted vehicle? Bring it! Just want to learn what these electric vehicles are all about? That’s cool too!

The Milwaukee Electric Car Club: Because gasoline is so 20th century.

Hack-A-Lantern: DIY Salvaged Zombie-beatin’ Flashlight!

Recently, I was hanging out at the Milwaukee Makerspace, working on a simple project, when a fellow Maker offered me a used 5AH lead acid battery.

The project I was working on involved using landscaping lighting, and right there on the “Hack Rack” were some old computer power supplies. Hmmm. We also happened to be talking about Zombie movies and TV shows, when it all clicked – I have the skills and materials to build an electric lantern from scratch using just the materials that are right here!

The project started by taking apart a computer power supply. I snipped the wires from switch and power cord connection close to the circuit board, so that I would have plenty of wire still soldered to the switch. After removing the circuit board and cooling fan, I had a nice empty box to use as the case for the lantern.

Next, I snipped out the fan grate, to allow for the 12V 11watt landscaping light bulb. These things are designed to run on 12AC from a transformer, but nothing is stopping me from running it on a 12V battery instead!

I crimped on a couple of spade connectors onto the wires from the switch to go to the battery and the bulb. I also wired the power port so that it was unswitched (always connects to the battery) that way, I could use it to recharge the battery without having to open the case. I would just clip the external battery charger that I already had to the two pins of the port.

Once the wiring was done, I checked the connections, turned it on and off a couple of time, and then glued the bulb in place with silicon.

A key feature of a lantern (as opposed to a flashlight) is that it has a distinct handle on the top, which the lantern hangs from. When I’ve made handles before, I’ve usually used a pair of bolts with spacers and some sort of cross-piece of wood or metal. However, I didn’t have anything like that handy, and it didn’t seem to fit the theme of the lantern either.

I DID have all the extra wiring from inside the power supply. The main bit of it was already bundled and had a nice connector on the end. I drilled two 1/2″ holes in the case cover and ran the cable through it, then back through the other hole, and pinned it in place with a few zip-ties.

I also glued two bits of foam on the inside of the case to cushion and help hold in place the battery. With that I put the cover back on and reinstalled the four cover screws.

There ya go! A lantern made completely from repurposed, recycled, and salvaged materials! Whether you like tinkering, being ready for the zombies, or just like being prepared, the Hack-A-Lantern is for you. Why don’t you try making one and see what you come up with!

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