Month: November 2013

Examining Vintage Printer Server Hardward For Apple II

November 13, 2013 by 19 Comments

II-easy-print-reverse-engineering

Need to share a printer between several Apple II computers? Of course you don’t, but back in the day this would have been a really awesome piece of hardware to own. It’s a Pacemark iiEasy Print (we’re not sure on the capitalization of the name so talk amongst yourselves). It is an automatic buffer and switch that you can have now-a-days for just a couple of Hamiltons. [David] doesn’t mention where he “acquired” his specimen, but all the details about his adventures reverse engineering the card are shared in detail.

First off, we have to mention his unorthodox bench tools. To the untrained eye it would appear that he has attached the iiEasy Print to a Commodore 64; and that eye would be right. [David] says he uses the C64 something like an Arduino (if that’s even possible). The green card is plugged into the C64 memory bus, connecting to the DIP socket breakout board on the left and the chip select pins for most of the other IC’s on the original board. The gist of this setup is that it’s simple to use the “passthrough” DIP socket to monitor what the 6502-like processor is doing, while mapping the memory with the help of the chip select signals.

What did he learn from all this? Quite a lot but you might as well click that link above and hear it from his own mouth.

39 Raspberry Pi 3D Scanner

November 13, 2013 by 30 Comments

[Richard] just posted an Instructable on his ridiculously cool 39 Pi 3D Scanner! That’s right. 39 individual Raspberry Pies with camera modules.

But why? Well, [Richard] loves 3D printing, Arduinos, Raspberry pies, and his kids. He wanted to make some 3D models of his kids (because pictures are so last century), so he started looking into 3D scanners. Unfortunately almost all designs he found require the subject to sit still for a while — something his 2-year old is not a fan of. So he started pondering a way to take all the pictures in one go, to give him the ability to generate 3D models on the fly — without the wait. 

He originally looked at buying 39 cheap digital cameras, but didn’t want to have all the images on separate SD cards, as it would be rather tedious to extract all the images. Using the Raspberries on the other hand, he can grab them all off a network. So he set off to build a very awesome (and somewhat expensive) life-size 3D scanning booth. Full details are available on his blog at www.pi3dscan.com

Stick around after the break to see it in action at Maker Faire Groningen 2013!

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Peltier Joule Thief Power Supply

November 12, 2013 by 20 Comments

[Steven] manages to power an LED for 15 minutes using hot and cold water as a battery. He does this using the thermoelectric effect also known as the Seebeck effect, Peltier effect or Thomson effect. This isn’t particularly new; in fact there are commercial products that you can use to charge a cell phone using a small campfire or internal burner that works on the same principle.

What is interesting about [Steven’s] device is that he uses a salvaged Peltier device not meant for generating electricity, coupled with a home built joule thief circuit. In the video he describes how the joule thief functions and powers the LED using the small voltage generated by the Peltier device. The energy for the thermoelectric effect is conducted from a hot water bath through aluminum plates, through the positive and negative sides of the Peltier device, through more aluminum plates and finally into a cold water bath. As the heat energy transfers through the Peltier device a small electric current is generated and flows in two small wires coming out the side of the device.  The energy generated by the Peltier device is stored in the joule thief and periodically dumped at a voltage high enough to forward bias the LED “on” for a brief moment. Technically the LED is flashing but at a frequency too high for our eyes to see. As the hot water bath cools, the LED goes from very bright, to dim, to off in about 15 minutes.

Not a very practical power supply but still quite the parlor trick. He wraps up the tutorial specifying that a TEG thermoelectric generator would be a much better choice for generating power and can handle much higher temperatures. You can watch the video after the break.

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Sailing With An Autopilot

November 12, 2013 by 11 Comments

sailboat

After seeing an autopilot for a kayak a few days ago, [Mike] thought he should send in his version of a water-borne autopilot. Compared to something that fits in a one-man kayak, [Mike]’s creation is a monstrous device, able to keep a largeish sailboat on a constant heading.

To keep track of the ship’s bearing, [Mike] is using a very cool digital compass that uses LEDs to keep a steady heading. Also included is an amazingly professional and very expensive 6 axis IMU. To actually steer the ship, [Mike] is using a linear actuator attached to the tiller powered by a huge 60 Amp motor controller. The actuator only draws about 750 mA, but if [Mike] ever needs an autopilot for a container ship or super tanker, the power is right there.

For control, [Mike] ended up using an Arduino, 16-button keypad, and an LCD display. With this, he can put his autopilot into idle, calibration, and run modes, as well as changing the ship’s heading by 1, 10, and 100 degrees port or starboard.

From a day of sailing, [Mike] can safely say his autopilot works very well. It’s able to keep a constant heading going downwind, and even has enough smarts to tack upwind.

Videos below.

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A Simple Servo Hack For An Iron Man Helmet

November 12, 2013 by 12 Comments

iron man helmet

[James] makes some seriously awesome Iron Man props. In one of his latest helmet builds, he came across a handy hack to lock the faceplate servo in place.

You see, as awesome as it is walking around like Iron Man all day, you’re going to want to keep your faceplate up for extended periods of time. Simply holding the servo in place electronically is a waste of power, and results in the annoying sound of a servo under strain. On the other hand, cutting power to it will keep it in place momentarily — but it will also start to close under the force of gravity.

The solution is actually quite simple, by reprogramming the Picaxe-08M microcontroller, the board now shorts the motor terminals to hold it in place. This is called magnetic motor braking, and it works by creating a closed loop that makes it much harder to induce a current under load. We once added this feature to a motorized push-scooter — it’d stop on a dime, although you wouldn’t…

Stick around after the break to see an extremely in depth video on how he setup the entire system.

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Printing Printed Circuit Boards

November 12, 2013 by 65 Comments

circuit

We really respect the old timers out there and their amazing ways of crafting PCBs; they used black tape on clear acetate sheets to create single layers of PCBs with a photoetching process. Now creating a PCB is a simple matter of opening up a CAD package, but like the old timers we’re still dealing with nasty chemicals or long shipping times from China.

The EX¹, a new robot on Kickstarter – hopes to change that. They’ve created a PCB fabrication process that’s as simple as printing something with an inkjet printer. Just put in a piece of substrate – anything from Kapton to acrylic to fabric – and in a few minutes you have a single-sided PCB in your hands.

The printer dispenses two chemicals, silver nitrate and ascorbic acid, that react and produce traces and pads for the circuit. Right now, the EX¹ is limited to single-side boards, but experiments on creating multi layer boards are ongoing.

In any event, we’re really impressed with how simple the EX¹ setup actually is. Inkjet is a mature, well understood technology with more than enough resolution for simple homebrew circuits, and the AgNO3 + Vitamin C formula could easily be adapted to an inkjet printer modification.

Building A Better Serial Camera

November 12, 2013 by 22 Comments

If your next project does anything with cameras or machine vision, you’ll probably be looking at something like a USB webcam attached to an ARM board or a netbook. Sometimes, though, that setup blows will blow your budget – power or otherwise – out of the water. For small projects, you’re limited to small, serial-accessible cameras, and in that domain you really don’t have a lot of choices.

[Ibrahim] realized the cheapest serial cameras are about $35, and with basic image processing that cost skyrockets up to about $100. He set out to build his own alternative, and ended up with an awesome serial camera module that should only cost about $15 in quantity.

The module is built around an STM32F4 microcontroller running at 168 MHz. This micro has a DCMI port to which a OV9650 camera is attached. The resolution ends up being 1280×1024, far better than other serial cameras.

Already [Ibrahim] has the hardware working and a few demo apps. He has a real time color tracking demo (video below) up and running and a machine vision repo for his tiny camera. Now if we could only get a few of these boards on Tindie.

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