You’ve Never See A Solid-State Oscilloscope Like This One

August 25, 2018 by 44 Comments

Remember a the time before oscilloscopes had a brain? It’s easy to forget as we’ve become accustomed to a class of simple solid state oscilloscope using a microcontroller as signal processor and a small LCD display to show the resulting waveforms. They are commonly available as inexpensive kits, and while their bandwidth is not huge they give a good account of themselves in low frequency applications. But of course, originally the signal processing was handled in a much simpler way.

[SimpleTronic] reminds us that a small solid state oscilloscope does not need a microcontroller, with a ‘scope on a breadboard that displays waveforms on an LED matrix in a much more traditional manner. This is very much an analogue oscilloscope, in which the X deflection circuitry of the CRT is replaced by a decade counter stepping through the columns of LEDs on the display, and the Y deflection circuitry by some analogue signal conditioning followed by an LM3914 bar graph display chip driving the display rows. There are a few refinements such as a trigger circuit, but it remains a very understandable and surprisingly simple device.

It has a claimed bandwidth of 40 kHz defined by its sweep ranges rather than its analogue bandwidth, and an input voltage range from 50 mVpp to 50 Vpp. It’s hardly a useful instrument due to its low bandwidth, but its strength lies in novelty and in understanding a traditional oscilloscope rather than in its utility. You can see it in action in the video we’ve placed below the break.

‘Scopes of limited use appear from time to time on these pages. A favourite of ours is this soldering iron.

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The Electric Vehicles Of Electromagnetic FIeld: The Selby

August 25, 2018 by 5 Comments

A couple of weekends ago on a farm in rural England with a cider orchard and a very good line in free-range pork sausages, there was the first get-together of the nascent British Hacky Racers series of competitions for comedic small electric vehicles. At the event, [Mark Mellors] shot a set of video interviews with each of the attendees asking them to describe their vehicles in detail, and we’d like to present the first of them here.

The Selby is unique among all the Hacky Racers in being a six-wheeler. It’s the creation of [Michael West] of MK Makerspace, and it bears a curious resemblance to a pair of PowaKaddy golf buggies grafted together. The resulting vehicle has four driven wheels and two steering wheels, and though it is hardly a speedy machine this extra drive gives it what is probably the most hefty pulling power of all the contestants. In the video below it appears without bodywork, but we are told that something impressive will sit upon it when it appears at Electromagnetic Field.

View of motors fed with 24 V driving the rear wheels

I should own up, that the Selby is a familiar to Hackaday, as I’m also an MK Makerspace member. I’ve seen it progress from two worn-out golf trolleys to its current state, and seen first hand some of the engineering challenges that has presented. The PowaKaddy buggies of that vintage are extremely well-engineered, with a Curtis controller that is still comfortably within spec even when driving four motors instead of two. Unusually for a Hacky Racer the power comes from a pair of huge lead-acid batteries, as these were the power source supplied with the PowaKaddy from new and it made little sense to change them. Gearing is fixed at golf-course speeds, and braking comes from a pair of brakes fitted on the motors. The motors themselves are simple DC affairs, with significant weatherproofing.

Cutting and shutting the two PowaKaddys was straightforward enough, but introduced a warp to the chassis that was solved by your Hackaday scribe hanging on the end of a lever formed from a long piece of 4-by-2 while [Mike] and friends stood on the other end of the Selby.

As a driving experience it’s exciting enough but lacks the speed of some of its competitors. Where it really comes into its own though is off-road, as the multi-wheel drive and broad treaded tyres power it across mud and offer powersliding opportunities on wet grass.

We’ve covered a couple of Hacky Racers so far in our mini-series on the Electric Vehicles of Electromagnetic Field, and we’ll bring you a few more before the event. Meanwhile feast your eyes on a Sinclair C5, and an Austin 7 inspired mobility scooter conversion.

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Electric Shower Head Teardown Makes Us Wince

August 25, 2018 by 141 Comments

We have bought some really amazing stuff from the Chinese online shops. We’ve also bought stuff that was… less than satisfactory, let’s say. At the prices you pay, you usually just chalk up the bad stuff as a cost of doing business. But [DiodeGoneWild] has a teardown of something that could be very dangerous if it wasn’t up to snuff: an electrically heated shower head. He says they are common in Latin America and have the nickname “suicide showers.”

We’ve seen the cute showerheads that change color, but those take batteries. What we are talking about here connects to the 220V main and draws 30A to instantly heat your shower water. Environmentally, that’s great since you don’t have a tank of water you keep heating and reheating just in case you need hot water. But you wouldn’t throw an AC radio in the tub, so you have to wonder just how safely this thing’s built. Well, you don’t have to wonder, because the videos below are going to show us.

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Raspberry Shake Detects Quakes

August 25, 2018 by 18 Comments

The Raspberry Pi’s goal, at least while it was being designed and built, was to promote computer science education by making it easier to access a working computer. What its low price tag also enabled was a revolution in distributed computing projects (among other things). One of those projects is the Raspberry Shake, a seismograph tool which can record nearby earthquakes.

Of course, the project just uses the Pi as a cost-effective computing solution. It runs custom software, but if you want to set up your own seismograph then you’ll also need some additional hardware. There are different versions of the Raspberry Shake, the simplest using a single Geophone which is a coil and magnet. Vibrations are detected by sensing the electric signal generated by the magnet moving within the coil of wire. Other models increase the count to three Geophones, or add in MEMS accelerometers, you can easily whip one of these up on your own bench.

The entire setup will fit nicely on a coffee table as well, making it much smaller (and cheaper) than a comparable professional seismograph. Once all of the Raspberry Shakes around the world were networked together, it gives an accurate, real-time view of seismic activity anywhere you can imagine. If you’ve ever been interested in geology or just want to see where the latest earthquake was, check out their projects. But you don’t need even a Raspberry Pi to see where the earthquakes are, thanks to a Hackaday Prize entry all you need is a Twitter account.

Thanks to [Rich Cochran] aka [AG6QR] for the tip!

RC Boat Goes Brushless For Speed & Reliability

August 24, 2018 by 17 Comments

Remote control boats can be great fun, and come in all manner of forms. There are unpowered sailcraft, speedboats that scream under the power of internal combustion, and of course, those that move under electric power. The brushless motor revolution of the past 20 years in particular has proven capable of creating some exciting RC watercraft, and [Matt K] decided he wanted to get on board.

[Matt] had owned a Kyosho Jetstream 1000 for several years, but found the nitro engine to be temperamental and not the most fun for high-jinx down at the lake. An old-school brushed motor setup with mechanical speed control similarly failed to excite. However, after experiencing the power of brushless in RC planes, [Matt] knew what he had to do.

Using an online calculator, [Matt] determined that his earlier nitro powerplant was putting out roughly 900 watts. When it came to going brushless, he decided to spec a Turnigy powerplant with twice as much power, along with the requisite speed controller. There was some work to do to integrate the new motor with the original propeller driveshaft and water cooling system, but in the end [Matt] ended up with a much faster boat that is a lot less hassle to set up and run.

Perhaps though, your RC boat needs brains, over brawn? Perhaps it’s time to look at autonomy…

Video after the break.

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Coffee machine current sensor hardware

Tracking The Office Coffee Machines Using Current Draw

August 24, 2018 by 16 Comments

Coffee is the lifeblood of hackers, IT workers, and apparently, IT workers who are also hackers. [Omerfarukz] is clearly the latter. He works as part of a large team spread over multiple floors, all with coffee machines, any one of which is fair game. The problem is knowing which one has coffee that is ready to pour. He needed a non-invasive way to monitor the coffee machines.

Coffee machine sensor voltage chartAfter contemplating a few solutions, he opted for one which wouldn’t offend the coffee gods. The machines use a high current to produce their heat, so he adapted some old remote control power sockets for the machines to plug into which would now monitor the current. A high current means the coffee is brewing and he knew that brewing takes one minute per cup, so the duration of the high current tells him the number of cups.

Having had no success with a current sensing transformer, he opted for an ACS712 chip, at heart a Hall effect sensor which outputs a voltage proportional to the test current. That goes to the IO pins of an ATtiny, and from there via serial to an ESP8266 and thence to Google Firebase for processing and notifying of IT workers in need of stimulation. For those wishing to partake, he’s posted the circuit on Github.

We’ve seen a few other non-invasive ways to do this monitoring. For example, there’s weighing the machines using a bathroom scale and the more manual phone-notifying alarm button.

This Hackable Phone Makes WiFi Calls.

August 24, 2018 by 24 Comments

Over the years, we’ve seen dozens of projects that sell themselves as an ‘Open Source’ cellphone, a hackable cellphone, or some other confabulation of a microcontroller, screen, and a cellular module. The WiPhone is not one of these projects. That’s not to say it’s not an Open Source phone that’s intended to be hackable. No, this is a DIY phone that doesn’t make cellular calls, because this is a phone that only works with SIP and VoIP apps. It’s a WiPhone, and something a lot of us have been waiting for.

The hardware for this WiFi enabled phone is extremely minimal, but there are some interesting tricks up its sleeve. Instead of letting the main microcontroller handle capturing all the button presses, the team behind the WiPhone are using a SN7326 key-scan controller. This cheap part is able to scan 64 buttons, although there are only 25 buttons on the phone. The audio board is a  WM8750BL, a cheap codec with a stereo microphone interface and a 400 mW speaker driver. The display is a simple SPI TFT, and apart from the microcontroller, that’s about it.

But it’s the microcontroller that makes it, and for that we turn to the incredible ESP-32. This chip has enough power to play Doom, be a Game Boy, and in this case, make and receive calls from a VoIP provider, scan and connect to WiFi networks, and yes, it can even play snake.

While this is just about the simplest phone you can imagine, and it only works where there’s a WiFi network, a device like this could be invaluable. And really, these days how far are you from a WiFi network you’re already connected to anyway?