electronics

You are currently browsing articles tagged electronics.

Yeah, free. If you’re starting a 3D printer project (such as RepRap) at your public K-12 school in the United States for the benefit of the students, then we’ll give you a free Sanguinololu v1.3a PCB to help you out (while supplies last). They typically sell for about $12-14. We won’t even charge you for shipping.

What is a 3D printer? Check out the video at the bottom of the page for an introduction.

Not a school but want one anyway? I’m selling some of them to raise funds for a printer for a local school. Just select “None – Buy one” for affiliation below, and I’ll send you the details. They’re $11, shipping included within the USA.

Sanguinololu 1.3a PCB

Sanguinololu 1.3a PCB

We don’t see any reason why kids shouldn’t have access 3D printing technology in their problem solving toolkit, and soldering up the electronics is all part of the fun. A club with only six kids raising $50 each could be well on its way to building and operating a 3D printer for its school, and while the electrionics can typically amount to 1/3 or more of the final build price, hopefully a free PCB will help ease the pain a bit.

Are you interested? Submit the form below for instructions on how to get your free Sanguinololu 1.3a PCB.

Name (required)
Email (required)
School (required)
Affiliation (required)
Description of Your Project (required)

What is a 3D Printer?

Here’s an introduction to the technology:

The shipping “estimator” at Mouser.com is a little vague, so I thought I’d post the results of a recent order. In general, you’re not going to know the shipping cost or the weight of your order until after it’s shipped.

My recent order totaled $189.12 and had 33 line items, including all kids of components (resistors, capacitors, ICs, connectors, crystals, buttons, crimp terminals, etc), in quantities ranging from 2 to 250, primarily for assembling four Sanguinololu circuit boards (with some exceptions, plus some other stuff).

Selecting residential delivery via USPS to North Carolina, USA, the Mouser shipping estimator listed $6.95 for 1 pound and $9.60 for 2 pounds. I guess that the order wouldn’t weigh any more than 2 pounds. The actual invoiced shipping cost turned out to be $7.74.

Although the order was prepared the previous night, I didn’t remember to actually place it until just after 4:00 EST on January 25, 2012 — so I had just missed the same-day shipping cut-off time. The order shipped on January 26, and the credit charge (for the exact invoice amount) was posted on January 27.

The delivery tracking updates were as follows:

  • Out for Delivery, January 28, 2012, 9:55 am, CHAPEL HILL, NC 27514
  • Sorting Complete, January 28, 2012, 9:45 am, CHAPEL HILL, NC 27514
  • Arrival at Post Office, January 28, 2012, 5:08 am, CHAPEL HILL, NC 27514
  • Electronic Shipping Info Received, January 27, 2012
  • Depart USPS Sort Facility, January 27, 2012, FORT WORTH, TX 76161
  • Processed at USPS Origin Sort Facility, January 26, 2012, 8:18 pm, FORT WORTH, TX 76161
  • Accepted at USPS Origin Sort Facility, January 26, 2012, 7:03 pm, MANSFIELD, TX 76063
One final note: Recently I’ve noticed that there are a number of different ways people pronounce Mouser. Recently I’ve heard Mouse-er (rhymes with house-er), Moze-ure (rhymes with rose-ure), and Mau-zer (rhymes with cows-er). So how do you pronounce Mouser? It’s pronounced Mau-zer (rhymes with cows-er), but I still like to think of it as Mouse-er.

I’ve set out to build a Prusa Mendel for $300. So far I think I’m doing pretty well. The top part is what I’ve already picked up, and the bottom part is what I have yet to purchase — that’s where I still have some flexibility in cost. The first column is the percentage of total cost for that part. Shipping charges for a group of items from the same supplier are listed with the first item in that group. [Note: This chart has been updated many times as I build, and as because I’m already up and running with my reprap 3D printer, there’s no longer anything left to purchase.]

Where I discovered mistakes, I’ve corrected them. For example, I actually ordered nylock #6 nuts instead of regular ones. In cases like these, I’ve just corrected the prices and pretended like I never incurred the cost of the wrong product.

There’s one important point I’d like to make out here: I was patient, I waited for good deals (and occasionally got exceptional ones), and I arranged some group buys for bulk discounts. Often if you agree to purchase larger quantities of a product, you can secure a discounted rate, and so that’s what I did where I could. You might not find all of the same deals I did, but you may get pretty close if you are patient and work with your suppliers.

I’ve added a table below that breaks out the electronics order, including what I had on hand, what I bought from ebay, and what I didn’t actually need. (Welcome Hack A Day readers!)

Finally, be sure to scroll to the right in the spreadsheet views for important notes or shortcuts on most line items.

Electronics

Well, I discovered that Popsicle is a brand name, so I’m officially renaming this little guy “StickBot” so the Popsicle police don’t come after me. To be clear, this little bot has nothing to do with Popsicle brand ice pops, and never did. My appologies Popsicle; I hope you still let me eat your ice pops because life just would not be the same without them.

Now that I’ve come clean, here’s a video that show how to assemble StickBot’s right eye. It’s an analog 555 timer-based 1Hz oscillator that controls the right/left PWM servo signals generated by the left eye.

This is the latest version, powered directly by four 1.5V LR61 batteries (similar to AAAA batteries, and often found inside 9V batteries). As a result, it does away with the voltage regulator.

Details for the previous version can be found here: StickBot V2.0 - Untethered!. The original tethered version can be found here: StickBot: A Simple 6-Legged Walker. I’ll try to get updated schematics and more assembly videos up soon.

I’ve had a few people ask me if I have a kit for this little critter. I’m working on one geared toward kids — it’s a fun project to do with kids, and it seems like they really learn a lot from it.

The parts for this eye include:

  • 555 Timer IC
  • 1k ohm resistor
  • 330k ohm resistor
  • 2.2uF capacitor
  • About 9 inches of Cat 5 network cable, phone cord, or other similar wire
  • Some electrical tape, solder, and soldering iron

Here’s a video of my very hackable 12-channel logic level shifter/translator with a voltage regulator. This video demonstrates how it works. There’s more detail here at the DIY 12-Channel Bidirectional Logic Level Shifter post.

In this example, it’s translating from 7.5V to 3.3V. In another example at the link above, I’ve demonstrated the hackability by wiring it up to drive a 3.3V Nokia 5110 LCD, using five of the 12 channels as logic level translators. Channel two is wired directly to 3.3V for power, channel three is wired directly to ground, and the transistor on channel nine is turned so that the 5V signal controls the gate, which allows PWM control of the LED with full power from the regulator.

Music: “Art Now” by AlexBeroza (CC BY 3.0)

40-pin female headers are inexpensive and easy to trim down to size, and with a dot of CA glue (super glue), you can even easily make other configurations, like 24. Sometimes they’re even described as “break-away” headers, although admittedly they don’t break away as easily as the male pin headers. Just keep in mind that if you don’t score it, it could shatter.

Someone was looking at one of my PCBs and commented that it’s “impossible to break them apart without destroying at least 2-3 pins each time.” Using this technique, I’ve never “destroyed” any more than one, and with a little care, the edges turn out quite nicely.

Music: “The New Music” by AlexBeroza (CC BY 3.0)

He we’re test-driving the our latest robot creation for the first time. It’s the boy’s design and made mostly of wood. The tires are o-rings, and there’s a 12V AA batter pack sandwiched between the two pieces of plywood. The system right now consists of a drive controller using a Modern Device‘s RBBB (small Arduino-compatible) and the Pololu TB6612FNG Dual Motor Driver Carrier, a robot controller, which is a standard Arduino Uno (which doesn’t do a whole lot right now expect forward messages from the remote), and a remote controller, which is another RBBB, joystick and display.

Right now there are two driving modes. The first is a tank drive, where, for example, if the joystick is moved far left, the right wheel moves forward at full speed and the left week backward at full speed. The second mode is what I call “target drive,” in which you set the target speed and direction of each wheel. Soft starting and stopping is built in to the controller, and the jerkiness you see sometimes is a bug in the keep-alive timer — if the robot stops getting messages in target drive mode, then it will stop.

Music is “Don’t you” by stefsax (CC BY 2.5).

Here’s a 12-channel bidirectional logic level shifter with a 3.3V power regulator that I designed so I could easily interface 5V circuits with cool 3.3V widgets like the ADXL345 accelerometer, the NRF24L01+ wireless transceiver, and the Nokia 5110 8448 LCD. For the one in the picture, I used round machine pin headers because I use it with hookup wire and those female headers are very easy to separate from 40-pin lengths.

12-channel Bidirectional Logic Level Shifter

DIY 12-channel Bidirectional Logic Level Shifter / Logic Level Translator, using AMS1117 and 2N7000 MOSFET pass transistor interfaces

Up to twelve 5-15V logic signals can go into one side and come out as 3.3V signals on the other side, or the other way around (3.3V signals go in and can be read as 5-15V signals) in any combination. The regulator portion converts 5 to 15V DC into a steady 3.3V for up to 1 amp.

In this video, I show how it works translating from 7.5V to 3.3V. The video is from the A Hackable 12-Channel Bidirectional Logic Level Shifter/Translator post.

Why did I not just use a 74HC4050 or some other logic level translator? Because this is much cooler! It’s bidirectional, it has twelve independent channels, in includes a 3.3V regulator, it’s inexpensive, it’s good soldering practice, and it’s hackable. In the photo below, I’ve wired it up to specifically drive a 3.3V Nokia 5110 LCD. It uses only five of the 12 channels as logic level translators, channel two is wired directly to 3.3V for power, and channel 3 is wired directly to ground. The transistor on channel nine is turned so that the 5V signal controls the gate, which allows PWM control of the LED with full power from the regulator. I’ve also used a different resistor. (More photos below.) And why no resistor arrays? Because resistors are usually inexpensive and on hand, and resistor arrays would limit hackability.

Logic Level Shifter Hacked for Nokia 5110 LCD

Logic Level Shifter Hacked for Nokia 5110 LCD

It’s essentially a AMS1117 3.3V regulator with capacitor at the top, and then an array of MOSFET pass transistor interfaces with n-channel 2N7000 MOSFETs. Each side is held high by a resistor 5.6k ohm resistor. If the 5V side is pulled low, the voltage from ground to source will be 2.7V because the diode becomes forward biased, and this turns on the transistor, pulling the 3.3V side low. If the 3.3V side is pulled low, the transistor also turns on with 3.3V, pulling the 5.5V side low.

It was designed using KiCAD (free), and PCBs were ordered through SeeedStudio’s Fusion PCB service. All the components are easily available online, at Digikey or on eBay. Here are the parts I used. The costs reflect per items costs for small bulk purchases (usually around 10-50 pieces) on eBay.

  • 1 AMS1117 3.3V 1A Voltage Regulator – 28¢ (datasheet)
  • 1 22uF electrolytic capacitor – 9¢
  • 12 2N7000 n-channel MOSFET – 60¢ for 12 (datasheet)
  • 24 5.6K ohm resistors – 43¢ for 24
  • 2 12-pin female headers (I used round ones for the one in the picture, but you should use the standard square ones if you’re not just using jumper wires.) – 29¢ for one 40-pin header, then cut into smaller pieces.
  • 2 2-pin female headers
  • 1 custom PCB – $1.12

The total unit cost was $2.81, plus time and solder. I’ve decided to sell off the extras either as PCBs or as kits, so let me know if you’re interested by commenting below.

Here’s the schematic and a screenshot of the PCB design, as well as a larger version of the image above:

I used the excellent Quick KICAD Library Component Builder recently to build a new component for eeschema in KiCAD, but when I imported the library, I got an error dialog that said, “Library component load error error in DRAW command X> occurred at line 38 .” [sic] Line 38 was line after the pin definitions — the “ENDDRAW” line.

KiCAD Eeschema Component Load Error message

KiCAD Eeschema Component Load Error message

It turns out the exception was caused by a space in a pin name: I had typed “SER IN” as the name of the pin, where I should have used an underscore and typed “SER_IN”. The library utility doesn’t prohibit this, and KiCAD clearly doesn’t like it.

Before I placed my order, I had questions about Seeed Studio Fusion PCB service turn-around time for shipping to the USA, and so I figure others might as well.

Here are details of my order of the ten 5cm square PCB’s shown in DMD: Dual Motor Doohickey (Modular RBBB and TB6612FNG Driver Board). The total cost was $13.42, including shipping (subtotal $9.90, plus $3.52 Registered Air Parcel). There were no “extras” (like 100% e-test, special colors or shipping methods, etc.).

  • 8/02/2011
    • 7:52 AM – Order placed. The total charge appeared on my PayPal account six minutes later, and the order confirmation with order number arrived at the same time.
    • 8:47 AM – I added the order number to the silkscreen layer of the PCB as requested and sent the gerber files to the email address specified about an hour after the order was placed. The design and gerbers were created with Fritzing.
    • 6:26 PM – Received an order update email: The order has been changed to status “Processing.”
  • 8/03/2011, 4:37 AM – Received an order update email: The order has been changed to status “In production.”
  • 8/04/2011, 1:49 AM – Received a person email from Dwin, I assume because when I ordered I had asked them to let me know if there were any problems: “Your PCB is under processing. If the file and design meets requirements, they will be processed and shipped in 4-6 working days.”
  • 8/08/2011
    • 4:33 AM – Received an order update email: The order has been changed to status “Traceable.”
    • 4:56 AM – Received an order update email: The order has been changed to status “Shipped.” (Yay!)
    • 9:21 PM – Received an order update email with a link for tracking the order.
  • 8/09/2011, 4:44 PM – Tracking status: “Acceptance” at Hong Kong; Tracking status: “Origin Post is Preparing Shipment.”
  • 8/11/2011, 10:53 AM – Tracking status: “Processed Through Sort Facility” at Hong Kong. “The item left Hong Kong for its destination.” (United States of America)
  • 8/23/2011
    • 7:29 AM – Tracking status: “Arrival at Unit” at my local post office.
    • 4:01 PMDelivered. I actually received 12 (instead of 10), and they all look great. They were very well packaged in a small corrugated cardboard box with lots of bubble wrap.

That’s 21 days or three calendar weeks start to finish — not bad at all! Tonight, I solder!

« Older entries § Newer entries »