Retro Wall Phone Becomes A Doorbell, And So Much More

We have to admit that this retasked retro phone wins on style points alone. The fact that it’s filled with so much functionality is icing on the cake.

The way [SuperKris] describes his build sounds like a classic case of feature creep. Version 1 was to be a simple doorbell, but [SuperKris] would soon learn that one does not simply replace an existing bell with a phone and get results. He did some research and found that the ringer inside the bakelite beauty needs much more voltage than the standard doorbell transformer supplies, so he designed a little H-bridge circuit to drive the solenoids. A few rounds of “while I’m at it” later, the phone was stuffed with electronics, including an Arduino and an NFR24 radio module that lets it connect to Domoticz, a home automation system. The phone’s rotary dial can now control up to 10 events and respond to alarms and alerts with different ring patterns. And, oh yes – it’s a doorbell too.

In general, we prefer to see old equipment restored rather than gutted and filled with new electronics. But we can certainly get behind any effort to retask old phones with no real place in modern telecommunications. We’ve seen a few of these before, like this desk telephone that can make cell calls.

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Ask Hackaday: Frequency Hopping on the nRF24l01+?

We’ve seen a lot of hacks with the nRF24l01+ 2.4 GHz radio modules. The tiny chips pack a lot of bang for the buck. Since the radios can switch frequencies relatively quickly, [Shubham Paul] decided to take advantage of this feature to make a rudimentary frequency-hopping communications channel.

The code is actually incredibly simple. Both the transmitter and receiver simply scan up and down over the defined channels. Because the clock speeds of any given pair of Arduinos are likely to be slightly different, it’s not a surprise that the radios eventually drift out of sync. Right now, as a quickie solution, [Shubham] is using a serial-port resynchronization: both are connected to the same computer, and he just tells them to get on the same channel. That’s not a horribly satisfying workaround. (But it’s a great start!)

Keeping two radios that are continually swapping channels in sync is no easy task, but it could possibly be made easier by taking advantage of the nRF’s acknowledge mode. If the delay between a sent acknowledge message and a received one were constant, these events (one on TX and one on RX) could be used to re-sync the two hopping cycles. All of this would probably require more temporal resolution than you’re going to get out of a microprocessor running Arduino code, but should be possible using hardware timers. But this is pure speculation. We briefly looked around and couldn’t find any working demos.

So Hackaday, how would you remotely sync two nRF24s on the cheap? Or is this a crazy idea? It might help to make transmissions more reliable in the face of 2.4 GHz band interference. Has anyone implemented their own frequency hopping scheme for the nRF24l01+?

Repurpose a Classroom Clicker for Great Justice

If you’ve been in a university class of a certain size, with a professor who wants to get live feedback from the students, you’ve probably been forced to buy a Turning Point “clicker”. Aside from the ridiculousness of making students pay for their professor’s instructional aides (do the make you pay extra for the chalk too?!?!) these clickers are a gauntlet thrown down to any right-minded hacker because they supposedly contain secrets.

[Nick] had one of these gadgets, and hopped right up on the shoulders of giants to turn it into a remote control that interfaces with his computer and drives a synthesizer, so he can work through the chord changes by clicking. His two references, to [Travis Goodspeed]’s nRF promiscuity hack and to [Taylor Killian]’s Arduino library for the clickers are a testament to why we need both reverse engineers doing the hard work and people who’ll wrap up the hard work in an easy-to-use library.

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Control Anything with a Universal Wireless Remote

If you aren’t already living on the spacecraft Discovery One, you may not have HAL listening to your every voice command. If that’s the case for you, as it is for us, you may have to resort to mashing buttons on little black monoliths like a primitive monkey. [Barnr]’s universal remote project, and some black PLA filament, will get you there in no time.

2001_obeliskThe remote is based on a nRF24 radios with a PIC to read the button presses. A Raspberry Pi and another nRF24 are listening on the other end. The code that runs either side of the connection is so minimal that both sides fit in the project description. It gets the job done, and it’s easily hackable. And with that, [barnr] can control anything that he can connect up to the Pi without getting up from his campfire.

While [barnr] is shy about his 3D design skills, we think that the box is fantastic. It’s got 3D-printed keycaps for the tactile switches that sit inside, and it’s an easily printed case. Maybe it’s a little blocky and, frankly monolithic, but it gets the job done. Aesthetics are for version 2.0.

When you build something yourself, and it’s not a HAL 9000, you pretty much need a way to control it. It’s no wonder we’ve seen so many projects on Hackaday. If your 2.4 GHz spectrum is too crowded to run a nRF24 remote, you might consider infrared: tiny, tiny, infrared. Or if you want to see the craziest remote that we’ve ever seen, check out this DTMF-over-cellphone build. But if you just want something sweet and minimal that gets the job done, [barnr]’s build is for you.

Thanks [Mikejand] for the tip!

Hackaday Prize Entry: BLE Beacon Library

While faking BLE advertising beacons using an nRF24L01+ module is nothing new, it’s become a heck of a lot easier now that [Pranav Gulati] has written some library code and a few examples for it.

[Pranav]’s work is based on [Dmitry Grinberg]’s epic bit-banging BLE research that we featured way back in 2013. And while the advertisement channel in BLE is limited in the amount of data it can send, a $1 nRF24 module and a power-thrifty microcontroller would be great for a battery-powered device that needs to send small amount of data infrequently for a really long time.

We’re not 100% sure where [Pranav] is going to take this project. Honestly, the library looks like it’s ready to use right now. If you’ve been holding off on making your own BLE-enabled flock of birds, or even if you just want to mess around with the protocol, your life has gotten a lot easier.

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Federico Musto of Arduino SRL Shows Off New ARM-based Arduino Boards

I caught up with Federico Musto, President and CEO of Arduino SRL, at the 2016 Bay Area Maker Faire. Their company is showing off several new boards being prepared for release as early as next month. In partnership with Nordic Semi and ST Microelectronics they have put together some very powerful offerings which we discuss in the video below.

arduino-primo-core-alicepad-star-otto-lcdThe new boards are called Arduino Primo, Arduino Core, Arduino Alicepad, and Arduino Otto.

The first up is the Primo, a board built to adhere to the UNO form factor. This one is packing an interesting punch. The main micro is not an Atmel chip, but a Nordic nRF52832 ARM Cortex-M4F chip. Besides being a significantly fast CPU with floating-point support, the Nordic IC also has built-in Bluetooth LE and NFC capabilities, and the board has a PCB antenna built in.

On an UNO this is where the silicon would end. But on the Primo you get two more controllers: an ESP8266 and an STM32F103. The former is obvious, it brings WiFi to the party (including over-the-air programming). The STM32 chip is there to provide peripheral control and debugging. Debugging is an interesting development and is hard to come by in the Arduino-sphere. This will use the OpenOCD standard, with platformio.org as the recommended GUI.

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Fuzzy Blanket Hides Serious Tech

Who needs the Internet of Things? Not this interactive, sound playback blanket! Instead, hidden within its soft fuzzy exterior, it makes use of a NRF24L01+ module to speak directly with its sound server.

The project was built for a school, and let the students record whatever sounds they think are important into a Raspberry Pi. Then, the students assembled the physical felt blanket, with the sensors sewn inside, and could play back their favorite sounds by clambering all over the floor. It’s a multi-sensory, participatory, DIY extravaganza. We wish we did cool stuff like that in grade school.

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What? Your “blankie” doesn’t transmit data to a Pure Data application? Well, [Dan Macnish] is here to help you change that. This well-written entry on Hackady.io describes the setup that he used to make the blanket’s multiple touch sensors send small packets over the air, and provides you with the Pd code to get it all working on GitHub..

8178811454644034915We like DIY music controllers a lot, and this simple setup stands to be more useful than just blanket-making. And in this age of everything-over-WiFi, it’s refreshing to see a straight-up 2.4 GHz radio build when that’s all that was necessary.

[Dan]’s complaint that the NRF24 modules could only reach 3m or so strikes us as strange though. Perhaps it’s because of all of the metal in close proximity to the NRF24’s antenna?