I promise these last several months haven’t been lazy ones. I’ve been working on a whole slew of new things, one of which is a tool to help beginner electronics hobbyists.

The 595 Shift Register Simulator

Shift Registers can be a bit puzzling to someone who’s unfamiliar with them. This tool will give you a chance to see how a shift register works in real time. You control each aspect of the register, at your own pace, and there are visual cues that will show what’s going on. Each pin on the chip is explained.

I hope you find it interesting and useful!

For beginners, the 595 series Shift Register isn’t easy to grasp. I’ve written an interactive 595 simulator so you can learn out the 595 works without having to wire one together. Play around with it. See if you can get it to produce the output you expect.

Tragically, it looks like your browser doesn’t support Canvas. 🙁

I would recommend the most recent versions of Firefox, or Safari

“Wait a minute! How does this work? I don’t get it!”

Picture a box that has a hole on either side. Inside it has 8 spaces you can fill up. Those spaces can either hold a zero (0) or a one (1). To fill up a space, you just push a new 0 or 1 into the left-hand side. When you do, the last space in the box gets pushed out the right hand side. At any time, you can open up the box and get all 8 values at once in the order you put them in there.

That’s kind of how a shift register works. You use the Serial In Value to tell the chip if you’re going to put a 1 or a 0 in. You use the Register Clock to tell the chip you’re pushing in a value on the left hand side. You use the Latch (or Shift Register Clock) to tell the chip you want to see all the values in the box.

Try the following:

1. Click the Serial Input Toggle button so that the SER pin goes red (that means it’s “HIGH”)
2. Click on the Clock button (Notice the SRCLK pin goes HIGH)
3. Now look at the Storage Register on the right. You’ve added a 1 to the beginning of the list!
4. If you click Clock again, you’ll see another 1 added to the left side.
5. Click the Serial Input Toggle again and the SER pin will go LOW.
6. Click Clock, now you’ll see a 0 added to the left side.
7. Now click on the Latch button. The values in the Storage Register are pushed out to the Shift Register. Now the output pins on the chip are also showing HIGH or LOW corresponding to the Shift Register. Lastly, you’ll see the 7-segment display has lit up as well.
8. Press the Storage Register Reclear button and press Latch. Now both registers are clear.

Now try those steps again, except press the Latch button after each Clock press. Notice what’s happening. Once you get the hang of it. see if you can make some numbers on the 7-segment display. Figure out which segments correspond to which pins on the shift register chip.

Here are a couple of characters for the 7-segment display to get you started:

1:  00001010
2:  11101100
E:  11110100
A: 11011110

At least one person was looking for part numbers for 595 shift registers. Here are a few:

74HC595
74HCT595
SN74HC595

What’s the difference?
Similar part numbers usually suggest compatibility between manufacturers. The specific part number may denote a variation. For instance, the 74HC595 differs from the 74HCT595 in that it can handle a wider variation in input voltage. For beginners, the variations usually aren’t particularly important. Check the data sheet for a particular chip.

If you’re looking for one and aren’t sure where to start, I’d recommend going to SparkFun. It’s not going to be the cheapest option, but they’ll give you the right chip if you’re uncertain.

About a year ago, I posted a couple of articles on my personal blog detailing the differences between Arduino Starter Kits that could be found online. A lot of people liked it and I received a whole host of requests to keep it updated and add more kits.

After lots of work and a lot of long days, I’ve finally got something that I think will be a real help: The Arduino Starter Kit Comparison Chart.

This chart version of the articles is a table-ized version of the kits, their components, explanations of (most) components, and short reviews for each kit.  I’ve tried to make it as practical and easy to use as possible.

Give it a shot, and let us know what you think!

So you want to get started with the Arduino, and a starter kit sounds like a good idea. We agree. The Arduino is an awesome platform, and with the right kit, you can really go places. It’s a tough job to go find all the kits out there and compare them, so we thought we’d make the job a little easier on you.

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Let’s face it: There are a lot of prototyping shields out there for your Arduino. Why add one to the mix? Well, we saw a need. When you’re working with your Arduino, you get in pretty deep before you have the need to actually build a custom setup on a shield. At that point, you might even ask yourself why you’re not making a custom shield. Sometimes you need something that will let you plug in some sensors, motors, a custom breadboard circuit, whatever it may be, without soldering your component away permanently. We know, because we wanted the same thing.

Our shield is designed to let you do that. It allows access to all the pins on the Arduino directly through screw-in terminal blocks.  There is also header space to break out 11 digital pins  for servo (or other actuator) controls. The remaining space on the shield contains a number of solderable vias, and a matched set of Vcc and Gnd rails to get power to whatever you stick there. The rails can be powered either by the Arduino 5v supply, or a secondary supply connected directly to the board.

Assembly instructions are listed in the Tutorials section.

Go Buy One! ->

Your Arduino is hungry for some expansion! Time to break out that kit and put the thing together!

This tutorial covers the assembly of the ConductiveResistance Protoshield.

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After a lot of work tuning the firmware and building a site for it, we’re finally ready to sell our first product: EerieEyes.

EerieEyes is a fairly simple circuit that, when turned on and put in the dark provides an eerie pair of eyes staring out from the darkness. We’re certainly not the first people to have this idea, but we’re pretty sure that we’re the first to build one on an AVR, and offer it up open source/open hardware.

We hope to be able to expand the firmware available here. Right now, EerieEyes blinks, and if you connect a Peizo or Vibrating motor up to the extension pads, it’ll buzz. There’s an ISP header available for onboard programming, and it also provides a breakout for all 5 GPIO pins.

Happy Halloween!

So you’ve got your EerieEyes Kit and you want to assemble it! You’ve come to the right place. Following are the instructions.

The kit you received may say “ScaryEyes” on it, instead of EerieEyes. This was our first go at a kit, and as a result we had a few errors. Rather than be wasteful, we decided to let it slide and try to make the best of it. The instructions are the same.

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