Hot or Not? Find Out How to Calculate Component Heat and Why You Should

How hot are your key components getting? There’s a good chance you’ve built a project and thought: “Well I guess I better slap a heat sink in there to be safe”. But when working on a more refined build you really need to calculate heat dissipation to ensure reliability. This is actually not tough at all. The numbers are right there in the datasheet. Yes, that datasheet packed with number, figures, tables, graphs, slogans, marketing statements, order numbers… you know right where to look, don’t you?

Hackaday has you covered on this one. In under 10 minutes [Bil Herd] will not only show how easy these calculations are, he’ll tell you where to look in the datasheets to get the info you need quickly.

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Impersonating FBI Agents And People Who Can Solder

[Dale Botkin], [N0XAS], is a competent designer for the amateur radio crowd and has a part-time business on the side selling a few kits. As anyone who owns a business, works in retail, or simply interacts with the general population will know, eventually you’ll have to deal with one of those customers. [Dale]‘s latest horror story (here’s the coral cache but that doesn’t seem to be working either) comes from someone who bought a little repeater controller. You’re looking at this customer’s handiwork above. It gets worse.

After this customer completely botched an assembly job, he contacted [Dale] for some technical assistance. [Dale] graciously accepted a return and received the above mess of solder, wires, and parts. Then an email disputing the Paypal charge arrived. The customer wanted a refund for the original kit and the cost of shipping it back.

Oh, but it gets better. After posting this story, [Dale] received yet another email from an FBI agent demanding that his original post be taken down. The email from the FBI came from a Czech domain, so of course this is a totally legit demand.

So there’s your, “worst customer ever” story from the world of kit electronics. The assembly is impressively bad, even for something that was ‘professionally installed by an electrician’, but mail fraud and impersonating federal officials just takes this over the top.


Quick note: any doxxing in the comments will be deleted, so just don’t do it.

Shopping Trolley is Wired for Camp

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[James] needed some cool transportation for the upcoming Easter Camp in New Zealand, so he created a custom motorized shopping trolley that is sure to turn heads. The base of this project is a standard mobility scooter, which conveniently has a modular design. All of the electronics have connectors for quick service and the entire rear axle and motor assembly pop off with the pull of a lever.

[James] had to do a bit of welding and chassis rework to achieve his goal of mounting a shopping cart top to the scooter’s frame. Once finished, though, the setup looked great. It was actually comfortable to sit in, as [James] made a cutout for the driver’s feet to pass through. The real fun came with the electronics. The trolley is the most wired mobility scooter mod we’ve ever seen. Most of the electronics are contained in a project box under the seat, with several Arduinos that control the various systems: interfacing with the original scooter electronics, a GPS receiver, and a GSM radio. [James] also went as far as to add RGB LED headlights, a horn, and a multi-tone siren from Jaycar.

Driving the trolley is simple. An arcade joystick selects the speed, and the scooter’s standard hand controls are used for forward, reverse, and steering. One of the more interesting mods [James] made was a custom Windows app to control the trolley via a USB radio module. The entire system can be secured, with the security code stored in NVRAM to prevent a power cycle from unlocking the system. [James] can even command the trolley to go forward or reverse from his touch screen. We’d love to see him add a steering servo to make it a completely remote-controlled solution, though this step would require some sort of clutch for manual control.

The final design works very well.  [James] may not win any drag races by keeping scooter’s original speed controls and associated electronics, but he did extend the range with larger batteries, so we’re sure the trolley will be a hit all over the camp. Similar projects have been built using the base of an electric wheelchair. If you have one that you want to control without invasive changes to the hardware, check out this accessibility hack which interfaces using a connector.

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A Much More DYI Air Gap Flash Unit

In reaction to the other air gap flash unit we featured a few days ago, [Eirik] sent us a tip about another one he recently made. In his setup, the duration of the flash peak intensity is around 300ns (1/3,333,333 of a second). As a reminder, an air flash unit consists of a circuit charging a high voltage capacitor, a circuit triggering a discharge on demand, a high voltage capacitor and the air flash tube itself. The flash tube contains two wires which are separated just enough to not spark over at max potential. Isolated from the other two, a third wire is placed in the tube. This wire is connected to a trigger/pulse transformer, which will ionize the gap between the two capacitor leads. This causes the gap to breakdown and a spark to form, thereby creating a flash of light.

[Eirik] constructed his flash tube using an olive jar and a glass test tube. As you can see from the (very nice) picture above, the spark travels along the glass test tube, making the quenching much faster than in an open air spark. [Eirik] built his own high voltage capacitor, using seven rolled capacitors of roughly 2nF each made with duct-tape, tin foil and overhead transparencies. For ‘safety’ they are stored in a PP-pipe. A look at the schematics and overall circuit shown on the website reveals how skilled [Eirik] is, making us think that this is more a nice creation than a hack.

Disclaimer: As with the previous airgap flash, high voltages are used here, so don’t do this at home.

Electromagnetic Field Camp

Emf Electromagnetic Field Camp is a three-day camping festival for people with an inquisitive mind or an interest in making things: hackers, geeks, scientists, engineers, artists, and crafters.

There will be people talking about everything from genetic modification to electronics, blacksmithing to high-energy physics, reverse engineering to lock picking, crocheting to carpentry, and quadcopters to beer brewing. If you want to talk, there’ll be space for you to do so, and plenty of people who will want to listen.

EMF is a volunteer effort by a non-profit group, inspired by European and US hacker camps like CCC, HAR, and toorcamp.  This year on Friday 31st August – Sunday 2nd September 2012 Will hold the first Uk meeting of its kind.

Events and activities will run throughout the day and into the evening, everything else (chats, debates, impromptu circus performances, orbital laser launches) will run as long as your collective energy lasts.

The Event is to be held at Pineham Park, Milton Keynes, UK.

As a Hackaday viewer you can get discounted tickets.

[thanks Jonty]

Printing point-to-point circuits on a 3D printer

[CarryTheWhat] put up an Instructable on his endeavours in printing circuit boards for solder free electronics. He managed to print a flashlight where the only non-printed parts are a pair of batteries and a couple of LEDs.

The circuit is a weird mix of point to point and Manhattan style circuit construction; after modeling a printed plastic plate, [CarryTheWhat] added a few custom component holders to hold LEDs, batteries, and other tiny electronic bits.

To deliver power to each electronic bit, the components are tied off on blue pegs. These pegs are attached to each other by conductive thread much like wirewrap circuit construction.

Right now, the circuits are extremely simple, but they really remind us of a few vintage ham radio rigs. While this method is most likely too complex to print 3D printer electronics (a much desired and elusive goal), it’s very possible to replicate some of the simpler projects we see on Hackaday.

[CarryTheWhat] put the models and files up on GitHub if you’d like to try out a build of your own.

ElectroDroid – your Android electronic reference app

Earlier this week, fellow Hack a Day-er [Mike Nathan] reviewed Adafruit’s new iPhone/iPad app Circuit Playground. The comments on [Mike]‘s review turned to suggesting ElectroDroid as an alternative to Circuit Playground. Surprisingly,  Hack a Day authors actually pay attention to the comments, so I’ve decided to throw my hat into the ring and offer up my review of ElectroDroid. For purposes of full disclosure, I have to add that I paid the $2.59 donation for a copy of ElectroDroid without ads, and have had no contact with the developers.

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