Using the ESP8266 as a Web-enabled sensor

A few months ago, the ESP8266 came onto the scene as a cheap way to add WiFi to just about any project that had a spare UART. Since then, a few people have figured out how to get this neat chip running custom firmware, opening the doors to an Internet of Things based around an ESP8266. [Marc] and [Xavi] just wrote up a quick tutorial on how to turn the ESP8266 into a WiFi sensor platform that will relay the state of a GPIO pin to the Internet.

If you’re going to replicate this project, you won’t be using the stock firmware on the ESP. Instead of the stock firmware, [Marc] and [Xavi] are using the Lua-based firmware that allows for access to a few GPIOs on the device and scripting support to make application development easy. To upload this firmware to the ESP, [Marc] and [Xavi] needed a standard FTDI USB to serial converter, a few AT commands through a terminal program, and a few bits of wire.

The circuit [Marc] and [Xavi] ended up demoing for this tutorial is a simple webpage that’s updated every time a button is pressed. This will be installed in the door of their hackerspace in Barcelona, but already they have a great example of the ESP8266 in use.

Cosplaying as HAL 9000

2001: A Space Odyssey is one of the greatest films of all time, but unlike every other masterpiece of SciFi, you’re not going find many people cosplaying as characters from the movie. Going as a monolith to a con would be hilarious, but [jacqueslelezard] had an even better idea in mind: a HAL 9000 costume.

The costume itself is just bits of painted cardboard, shiny material (we’d go with aluminum tape), some black mosquito netting to see out of, and in a stroke of brilliance, a tablet that will display HAL’s unblinking eye to con attendees. If you’re extraordinarily clever, it might be possible to sample lines from the movie and play them through the tablet. This is, unfortunately, the best way to replicate the voice of HAL, at least until someone gets the money to have [Douglas Rain] sit in for some voice work.

The only drawback to the costume is the propensity for the wearer to hit their head on doorways and low thresholds. This problem could be solved simply by increasing the size of the costume, but then you’re back in monolith territory. So, what do you want to be, a murderous computer or a galactic swiss army knife?

A 4-bit Computer From Discrete Transistors

Anyone reading this uses computers, and a few very cool people have built their own computer out of chips, [zaphod] is doing something even cooler over on he’s building a computer from discrete transistors.

Building a computer from individual components without chips isn’t something new – Minecraft players who aren’t into cheaty command blocks do it all the time, and there have been a few real-life builds that have rocked our socks. [zaphod] is following in this hallowed tradition by building a four-bit computer, complete with CPU, RAM, and ROM from transistors, diodes, resistors, wire, and a lot of solder.

The ROM for the computer is just a bunch of 16 DIP switches and 128 diodes, giving this computer 128 bits of storage. the RAM for this project is a bit of a hack – it’s an Arduino, but that’s only because [zaphod] doesn’t want to solder 640 transistors just yet. This setup does have its advantages, though: the entire contents of memory can be dumped to a computer through a serial monitor. The ALU is a 4-bit ripple-carry adder/subtractor, with plans for a comparison unit that will be responsible for JMP.

The project hasn’t been without its problems – the first design of the demux for the ROM access logic resulted in a jungle of wires, gates, and connections that [zaphod] couldn’t get a usable signal out of because of the limited gate fan-out of his gates. After looking at the problem, [zaphod] decided to look at how real demuxes were constructed, and eventually hit upon the correct way of doing things – inverters and ANDs.

It’s a beautiful project, and something that [zaphod] has been working for months on. He’s getting close to complete, if you don’t count soldering up the RAM, and already has a crude Larson scanner worked out.

Doing Unsafe Things With A Laser Watch

[Pierce Brosnan]-era James Bond had a beautiful Omega wristwatch. Of course as with any Bond gadget, it couldn’t just tell time; it needed to do something else. This watch had a laser, and [Patrick] figured he could replicate this build.

This is apretty normal 1.5W laser diode build, stuffed into a wrist-mountable device that will kill balloons. This is really a watch, though: press a button and this thing will tell time.

In the video below, [Patrick] goes over what damage this watch can do. He manages to pop some black balloons, burn holes in a CD case, light a few matches, cut cellotape, and put tiny burn marks in his wall. The battery won’t last long – just a few minutes – but more than enough to propel [Patrick] into Youtube stardom.

There are no plans or tutorials for the build, but the teardown [Patrick] shows is pretty impressive. To stuff a laser diode, battery, and clock into a watch-sized compartment, [Patrick] needed to turn down the metal buttons to fit everything into his watch case.

Because the comments for this post will invariable fill up with concern trolls, we’re just going to say, yes, this is incredibly unsafe, no one should ever do this, and it probably kills puppies.


Serial Surgery Saves Wacom Tablet from Landfill

Years ago, [Greg] got a Wacom Artpad II graphics tablet through Freecycle. What’s the catch, you ask? The stylus was long gone. When he found out how expensive a direct replacement would be, the tablet was laid to rest in his spare parts box. Fast forward a few years to the era of the phone-tablet hybrid and [Greg]’s subsequent realization that some of them use Wacom stylii. Eight bucks later, he’s in business, except that the tablet is serial. Wacom no longer supports serial tablets, so he had to convert it to USB.

With the help of the WaxBee project and a Teensy 2.0, he would be able to emulate an Intuous2 tablet by sniffing and re-encoding the packets.  Things got a little hairy when he went under the hood to remove the ADM202 TTL-to-RS232 chip with a Dremel—he accidentally gouged some of the pads it sat on as well as a few of the traces. Feeling frustrated, [Greg] took some high-res pictures of the board and posted them to a message board. As it turns out, those pictures helped him recreate the traces and get the tablet running. A little big of glue and tape later, he was in business. [Greg] even gave himself access to reprogram the Teensy.

Solving Arduino’s stk500_getsync() error

[psgarcha] took a year-old Arduino Uno on an international trip and upon returning found something was wrong. Every time he would try to upload, he would get the dreaded avrdude error, ‘stk500_getsync(): not in sync resp=0x00′. The Rx light would blink a few times during the attempted upload, but the tx light did not. Somehow, something was terribly wrong with the ‘duino, and [psgarcha] dug deep to figure out why.

To test the quality of the Arduino’s serial connection, [psgarcha] performed a loopback test; basically a wire plugged into the Tx and Rx pins of the Arduino. Sending a short message through the serial port showed the problem wasn’t the USB cable, the ATmega16u2 on the ‘duino, or any traces on the board. This would require more thought.

The main reason for the error would then be no communication between the computer and the ‘duino, the wrong COM port selected, the wrong board selected in the Arduino text editor, or timing errors or a corrupt bootloader. The first three errors were now out of the question, leaving timing errors and a corrupt bootloader. Troubleshooting then moved on to ordering a new programmer, and still this didn’t work with the broken Uno.

Frustrated with one of the greatest failures to become an Arduino tinkerer, [psgarcha] took a good, long look at the Uno board. He glanced over to an Arduino Mega board. Something looked different. On the Uno, the resonator had blown off. Problem found, at least.

Replacing the blown part with a hilariously large can crystal oscillator, [psgarcha] was back in business. This isn’t how you would fix 99% of getsync() errors, and it’s difficult imagining a situation where a this part would randomly blow, but if you’re ever looking at a nearly intractable problem, you need to start looking at what really shouldn’t fail.

Resonator my fix (1)

Awesome rework, though.


Cloning a Board from Pictures on the Internet

[Andrew] was a pretty cool guy in the early 90s with an awesome keyboard synth that did wavetable synthesis, sampling, a sequencer, and an effects processor. This was a strange era for storage; a reasonable amount of Flash memory was unheard of, and floppy disks ruled the land. [Andrew]’s synth, though, had the option to connect SCSI drives. Like all optional add ons for high-end equipment, the current price for the Ensoniq SCSI card is astronomical and [Andrew] figured he could build one of these cards himself.

Poking around eBay, [Andrew] found the card in question – just a few passives, some connectors, a voltage regulator, and an odd chip from AMD. This chip was a 33C93A, a SCSI controller, and a trip down the Chinese vendor rabbit hole netted him one for $7. Can’t do better than that.

With the datasheet for the chip in hand and a few reasonable assumptions on how the circuit worked, [Andrew] tried to figure draw the schematic. After doing that, he found another hobbyist that had attempted the same project a few years earlier. All the nets were identical, and all that was left to do was sending a board off to the fab.

A quick trip to Front Panel Express got [Andrew] a mounting bracket for the card, and after plugging it in to the synth revealed a new option – SCSI. It worked, and with an ancient SCSI CD-ROM drive, he had boatloads of offline storage for his synth. Great work, and something we’d love to see more of.