posts tagged with the keyword ‘electronics’

2016.12.04

Teensy BOB 1.4

The folks at Seeed Studio got in touch with me about their Fusion PCB Service and asked if I wanted to try it out. I’ve ordered stuff from Seeed Studio over the last five years or so, and I’ve never been disappointed with their products, and since they offered a coupon to save on an order, I decided to give it a try.

PCB Options

My previous PCB was the Teensy LC BOB v1.3. I ended up making a very small revision and released v1.4, which is the board I used for this Fusion PCB order. I’ve ordered these from OSH Park and they turned out good, so I wanted to compare ordering from Seeed Studio.

I should mention that I am not an Electrical Engineer, but a maker & hacker who learns things by trial and error. I’ve managed to get lucky with the PCBs I’ve ordered and part of that success has probably been due to the sensible defaults that OSH Park uses. By comparison, when uploading my Gerber files to the Fusion PCB service, I was a little overwhelmed. (See image above.) The choices… so many choices! While I didn’t know exactly what every option was, it was easy to choose them and see how it affected the price. Many options caused the price to go up by 2 or 3 or 10 times the amount. This made it easy to decide what not to choose. The one choice that is nice are the colors. OSH Park boards are purple, but you can get Fusion boards in green, red, yellow, blue, white, or black, which is great.

The one tricky form value you need to deal with is Dimensions. By default it is set to 70mm by 70mm, which comes out to $9.90 for 10 PCBs (though they seem to be changing that to 100mm by 100mm for $9.90, slightly better pricing.) You need to input the dimensions of your PCB as they are not detected by the Gerber files you upload. It’s a bit confusing… I guess for small PCBs you can panelize them. I should learn how to do that as it seems you can save money / get more PCBs by doing it.

The $9.90 is the base price for 10 PCBs, but adding more PCBs affects the total cost, but not by much for small boards. I could get 100 of my ATtinyNoisy boards for $18.32. That’s 10 times the number of boards for just twice the price! For the Teensy LC BOB v1.4 it’s $9.90 for 10 and $49.69 for 100. Economies of scale, yo.

Gerber View

One of the things that was missing when I ordered by PCBs was the preview of the board when I uploaded it. Well, either I missed it, or it’s a new feature that was recently added. Here’s what the Gerber preview looks like for my PCB in Fusion.

Teensy BOB 1.4

Teensy BOB 1.4

The boards turned out great. They look amazingly well done, and checking the 20 boards I received they all looked identical.

I actually placed two orders, for the first one I chose the fast shipping option, and the boards were completed within just a few days and shipped from Shenzhen, China to Milwaukee, Wisconsin in two days. Wow. That was for DHL shipping at about $20. Not bad at all.

The second order I chose the cheap shipping option, which was just $10. The boards were completed on November 18th (two days more than the first order) and were shipped, but as of December 4th (16 days later) I still have not received them. They were sent via Singapore Post and should be delivered to Rosemead, California, and then transferred to the USPS for delivery to me. I’m hoping they show up soon. (Update: They showed up on December 15, 2016.)

Teensy BOB 1.4

In summary, I was extremely pleased with the quality of the PCBs I got from the Fusion PCB Service from Seeed Studios. There are a lot of nice options when ordering, and volume pricing can make a lot of boards really cheap. The shipping costs and options are something to consider. With OSH Park the free shipping is nice, but of course you do end up waiting a while for the boards to be produced. OSH Park does have something called ‘Super Swift Service’ which adds $89 to your total. Oh, Fusion also has an “expedited” service that makes your boards in 24 hours, and that’s a $199 charge.

If I get to the point where I need a lot of PCBs for a project, or plan to sell them, Fusion would definitely make sense. If that’s what you need (perhaps for a Learn to Solder kit?) give Fusion a try.

2016.11.13

Stair Car

I’m going to be posting a bunch about a 2017 build for the Power Racing Series, and along the way I’ll be highlighting some parts of the build and explaining things. We’ll start with the motor controller, because being able to control the speed of a motor is crucial to building an electric vehicle. (Yes, we’re building an electric vehicle. Check out powerracingseries.org for more on this whole thing.)

DC Motor

Disclaimer: In some parts I’m going to keep things fairly simple.

Let’s start with some basics. A DC (direct current) motor spins when connected to power. In the diagram above we’re using a small motor and a 9 volt battery. Connect them together and the motor starts to spin. If you flip the wires (as in red wire to yellow wire, and black wire to green wire) the motor will spin in the opposite direction. This is how “brushed” DC motors work. There are also “brushless” motors, but we won’t get into those.

I sometimes like to refer to DC motors as “Don’t Care” motors. Want it to go the opposite direction? Flip the wires. Want it to go a bit slower? Give it a lower voltage. (Again, we’re simplifying things.)

Motor Controller

Here’s a motor controller. It has a connectors so you can connect a battery and a motor. You can’t make the motor go in reverse with this controller, but that’s okay for now. You can control the speed of the motor, but we don’t do it by lowering the voltage we do it by using “pulse width modulation”, commonly referred to as PWM. PWM is a method of controlling motors, lights, and other things by turning on and off the power really quickly. (Here’s a SparkFun article about PWM.) If you’re wondering why we don’t just lower the voltage (perhaps by raising the resistance) to make the motor go slower, read Why is PWM used to control DC motor speed instead of using a variable resistance?

Motor Controller

OK, so this motor controller comes with a potentiometer. When you spin the potentiometer is varies the resistance from 0 to 100K ohms. This get translated by the controller and feeds the appropriate PWM signal to make the motor go somewhere between not moving at all and full speed. The 100K pot also has two extra wires which work as a simple switch to turn the motor controller on and off.

Before we move on, a bit more about this controller. It’s from China, and it’s really cheap. I only recently discovered it’s a “Leadrise” controller after someone provided this Amazon link. You can find these on eBay for under $13. (Damn, that’s cheap!) I’m going to focus on doing a low-cost build, so keep that in mind along the way.

Throttle

The 100K pot is a nice way to test the controller and make your motor spin fast and slow, but you aren’t going to want a little potentiometer on your electric vehicle! Let’s find a throttle. Now, motor controllers of this variety typically require a “0-5V” throttle, or a “0-5K throttle”. The good news is, the 0-5V throttles are really cheap, the bad news is, this controller requires a 0-5K throttle, which are not cheap.

Magura makes a nice 0-5K throttle. You can find them for around $50 or so. There’s also a 0-5K thumb throttle that’s a bit cheaper. Any of these 0-5K throttles will work fine with this controller, and if you can decipher which wires are which you can cut off the 100K pot and wire in the 0-5K throttle. Easy, right!?

In a future post we’ll get into connecting up the throttle, and after that we’ll look at adding in reverse, and eventually get into building our own throttle controller that will allow us to use very cheap 0-5V throttles with this controller.

2016.11.05

Cameron

Alex

Katrina

Maks

Megan

Sadie

Stefanie

Sarah

Malcolm

Raven

Ali

Chance

We’re already half way through the semester and finished our third assignment for Electronics and Sculpture last week. Assignment 3 requires analog input and output for the project. (Assignment 1 is purely digital, and Assignment 2 requires analog input for control.) And yes, the class is called “Electronics and Sculpture” but it could just as easily be named “Arduino for Artists”.

Projects have varied from very interactive to installations to mostly sculptural with some electronics added in. I find that students do the best work when they can take what they are learning in class and combine it with their own practice, or what they are learning in other classes. The Digital Fabrication students definitely have an advantage here, and I wish all of the students had access to digital fabrication tools, though we just wouldn’t have time to cover it all in the 318 class. (That’s not to say the work of non-Digital Fabrication students is lacking in any way, and I’ve seen some great work using very simple material and tools. As always, art is a combination of things, including concepts, themes, ideas, technical skills and abilities, and more.)

We’re currently in the middle of the midterm project, and things are coming together quite well. Critique is in two weeks, and after that we launch right into the final project. (Since there isn’t an Arts+Tech Night this semester, we’ll probably just push the final critique onto the date that our final exam is scheduled for.)

2016.06.14

Name Tag

I woke up early on Sunday and had an idea for a project, and since I had a bunch of copper boards laying around, and just got some Liquid Tin, I made a super-simple name tag PCB.

Design filled

I started by designing in Inkscape with a canvas slightly larger than what I needed, and a cutting guide the exact size of my copper board.

Design outlined

Here’s the outline of the design, which I exported as a DXF file. The outer line was useful in making a (near) perfect alignment when I put the vinyl on the copper board.

Silhouette

I then imported the DXF file into the Silhouette Studio software so I could cut some vinyl to use as a resist for etching. (As mentioned previously, my etching solution is hydrogen peroxide, vinegar, and a bit of salt.)

Liquid Tin

Etching took over 75 minutes, but after it was done and cleaned off I dropped it into the Liquid Tin. It started getting bright and shiny immediately! (Sorry, no photos of the bare copper because I was working fast.)

LED & resistor

I soldered a blinking LED and a resistor in place, and since I still don’t have a tiny drill at home I went with surface mount of through-hole components, which works fine.

Battery

I also needed power, so I added a CR2032 battery and a binder clip along with a wire. The bottom of the battery (positive) goes against the PCB while the top (negative) gets a wire held against it with the binder clip. (Pretty much just borrowing heavily from the Learn to Solder Kit.)

Name Tag

I did end up drilling and filing a slot for the name tag clip thing, which I stole from my Milwaukee Makerspace badge.

Name Tag

Blink Blink! Maybe I’ll wear it to the National Maker Faire! I’ve got a few more ideas to build circuits that are one part electronics and one part art, so stay tuned!

2015.11.22

Click Whir Squee

Occasionally I show up at Milwaukee Makerspace with no clear idea of what might happen when I’m there. This piece, titled “Click Whir Squee” is the result of one such visit. Another member brought in a box of old computer hardware, including a Hewlett Packard Colorado T100E Tape Backup Drive. Being a fan of old technology (1997 is old, right?) I opened up the drive to take a look inside. I also powered it on and stuck a tape in it. The drive came to life and unspooled the tape and made a lot of spinning motor and tape loading sounds. Not everyone knows what these things sound like. It brought back some memories. (At my first job in the tech industry I had to load daily backup tapes into two tape drives. I remember the sound fondly.)

I somehow decided I should mount the tape drive to a piece of wood for display, so I went to the Wood Shop and started cutting up some scrap wood I found. Steve showed up to do some training, so I sat in on that for a bit so I could use the compound miter saw and the band saw. I had all the pieces cut by the end of the evening and knew how I was going to mount it.

I ended up taking all the pieces home and assembling it in my basement workshop. I manage to only split one piece of wood. Just a minor split, but a reminder to slow down when working with wood. The rest of the assembly went very smooth.

Click Whir Squee

Since the majority of fun with this drive is the startup sequence, I decided it should continually turn on, do its thing, then turn off, and keep repeating that. I’ve been playing with ATtiny85 chips lately, so I put one into service to trigger a 5 volt relay (which I also grabbed from Milwaukee Makerspace) and put the following Arduino code on it.


/*
 * TapeDriver.ino
 */

int relayPin = 3;
int onTime = 70000;
int offTime = 15000;

void setup() {
  pinMode(relayPin, OUTPUT);
}

void loop() {
   digitalWrite(relayPin, LOW);
   delay(onTime);
   digitalWrite(relayPin, HIGH);
   delay(offTime);
}

Yes, this is pretty much a glorified blink sketch. Sometimes the simplest things are exactly what you need. (Astute readers will see that the device will be on for 70 seconds, and then off for 15 seconds, and repeat indefinitely.)

Click Whir Squee

To power the ATtiny85 and the relay I found a Samsung phone charger on the Hack Rack at Milwaukee Makerspace. It even had a long cord, which was quite useful. You can also see one of the tapes that this machine uses. Now, if you really want to find some contrasts, consider that the modern day phone charger pictured here was used to charge a phone that probably had 8GB (or more) of solid state storage. The tape next to it could store 400MB of data (or 800MB of compressed data.) I should have included a MicroSD card which can store 8GB of data that I routinely buy for about $6 USD.

Click Whir Squee

Click Whir Squee

Since I removed the case there was no indication of what this thing was. I felt I should have something that told a bit of the story. I chose to mount the beige power pack, with “Hewlett Packard” emblazoned on it prominently.

Click Whir Squee

Oh, and while the whir of the motor is quite satisfying, we can do better. There is a wooden arm to which you can affix a small piece of material with a binder clip, which will then be activated when the primary motor spins. Fans of baseball cards and bicycle spokes, this one is for you! I call the “Annoy-o-tron” mode. (Look, if you’re going to use an ATtiny in an Annoy-o-tron, at least be original, right?) I’ve experimented with paper, vinyl, and plastic, but finally settled on a piece from an anti-static bag which some electronics were shipped to me in. It seemed fitting.

Click Whir Squee

Click Whir Squee

Click Whir Squee

Gallery owners and curators take note! This piece is ready to be mounted to a wall, and needs just two outlets to power it. It’s pretty much guaranteed to amuse some visitors while annoying other visitors. Art isn’t always about being pretty.

Enjoy the video below which allows you to experience this wonderful piece over the Internet while in the comfort of your own home (probably while wearing pajamas.)

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