A Description of Maddening Battery Terminology

Once again, [Afroman] is here for you, this time breaking down electrolyte and the terminology behind batteries.

Volts and Amps are easy mode, but what about Amp hours? They’re not coulombs per second hours, because that wouldn’t make any sense. An Amp hour is a completely different unit podcast, where a 1Ah battery can supply one amp for one hour, or two amps for 30 minutes, or 500 mA for two hours.

Okay, what if you take two batteries and put them in series? That would double the voltage, but have the same Ah rating as a single cell. Does this mean there is the same amount of energy in two batteries as what is found in a single cell? No, so we need a new unit: the Watt hour. That’s Volts times Amp hours, or more incorrectly, one joule per second hour.

Now it’s a question of the number of cells in a battery. What’s the terminology for the number of cells? S. If there are three cells in a battery, that battery has a 3S rating. You would think that C would be the best letter of the alphabet to use for this metric, but C is entirely different. Nothing here makes any sense at all.

What is C? That’s related to the number of amps a battery can discharge safely. If a 20C battery can discharge 2200mAh, it can deliver a maximum current of 44 A, with 20C times 2.2Ah being 44A.

So there you go. A complete description of something you can’t use logic and inference to reason through. Video below.

Continue reading “A Description of Maddening Battery Terminology”

Reanimating a Philips HDD 1420 MP3 Player

[OiD] had a dusty, old, forgotten Philips HDD1420 GoGear mp3 player kicking around his place. As you can imagine, the battery was dead. He had no charger or connector for the thing, but decided to try to resurrect it anyway.

He thought it would simply be a matter of providing alternative power, but the GoGear wasn’t having it and insisted on being connected to a computer. He had some luck consulting Pinouts.ru and found Philips’ own device manager software, but it still wasn’t easy. The device manager doesn’t work on Windows 7. He tried an XP box, but it didn’t detect the device.

Finally, he discovered that the hard drive was kaput and replaced it with an 8GB Microdrive. That helped, but he still had a hard row to hoe. [OiD] formatted the new HD and gave it the official firmware, but still had to replace some system files according to the Philips manual. He ended up using RockBox to reanimate it and decided to keep it on the device.

There was still an issue with charging, though. It has an IC that handles selection of either the proprietary external adapter or USB power, but the RockBox firmware doesn’t implement switching and defaults to the adapter. Several tweaks and a hacked-in mini USB later, the patient is in stable condition and cranking out the tunes.

ESP8266 Distance Testing

With progress slowly being made on turning the ESP8266 UART to WiFi module into something great, there is still the question of what the range is for the radio in this tiny IoT wonder. [CNLohr] has some test results for you, and the results are surprisingly good.

Connecting to the WiFi module through a TPLink WR841N router, [CN] as able to ping the module at 479 meters with a huge rubber duck antenna soldered on, or 366 meters with the PCB antenna. Wanting to test out the maximum range, [CN] and his friends dug out a Ubiquiti M2 dish and were able to drive 4.28 kilometers away from the module and still ping it.

Using a dish and a rubber duck antenna is an exercise in excess, though: no one is going to use a dish for an Internet of Things thing, but if you want to carry this experiment to its logical conclusion, there’s no reason to think an ESP8266 won’t connect, so long as you have line of sight and a huge antenna.

There’s still a lot of work to be done on this module. It’s capable of running custom code, and since you can pick this module up for less than $5 USD, it’s an interesting platform for whatever WiFi project you have in mind.

Bring A Hack at World Maker Faire 2014

After a hard Saturday at World Maker Faire, some of the best and brightest in the Hacker/Maker community descended on The Holiday Inn for “Bring A Hack”. Created by [Jeri Ellsworth] several years ago at the Bay Area Maker Faire, Bring A Hack (BAH) is an informal gathering. Sometimes a dinner, sometimes a group getting together at a local bar, BAH is has just one rule: You have to bring a hack!

[Sophi Kravitz] has become the unofficial event organizer for BAH in New York. This year she did a bit of live hacking, as she converted her Wobble Wonder headgear from wired to wireless control.

[Chris Gammell] brought his original Bench BudEE from Contextual Electronics. He showed off a few of his board customizations, including making a TSSOP part fit on the wrong footprint.

BAH-eggbotsmall[Windell and Lenore] from Evil Mad Scientist Laboratories brought a few hacks along. They picked up an old Radio Shack music player chip at the Electronics Flea Market and built it up on a breadboard. Also on display was their new EggBot Pro. The Pro is a beautifully machined version of the eggbot. Everything is built strong to withstand the sort of duty an EggBot would see at a hackerspace or public library. [Windell] was full of surprises, as he also gave everyone chunks of Sal Ammoniac, which is a great way to bring the tin back to a tired soldering iron tip. The hack was that he found his Sal Ammoniac at a local Indian grocery in the Bay Area. Check out [Windell’s] blog entry for more information.

BAH-diyVRSmall[Cal Howard] brought his DIY VR goggles. [Cal] converted a Kindle Fire into an Oculus Rift style head mounted display by adding a couple of magnifying lenses, some bamboo kebab sticks to hold the lenses in place. Judicious use of cardboard and duct tape completed the project. His current hurdle is getting past the Fire’s lack of an accelerometer. [Cal] planned to spend Sunday at Maker Faire adding one of his own!

As the hour grew late, everyone started to trickle out. Tired but happy from a long day at Maker Faire, the Bring A Hacker partygoers headed back to their hotels to get some sleep before World Maker Faire’s final day.

Countdown to Finals

There can be only 5.

This Sunday Night we will snapshot the state of the final 50 entries for The Hackaday Prize. Our panel of Launch Judges will then begin the difficult task of choosing the five projects which best exemplify the virtues of the challenge: Openness, Connectedness, Innovation, Wow Factor, Reproducibility, and User Experience.

Want to help your favorite project make the finals? Get in there and take a look at their write-ups. Leave a polite comment on the project page that mentions the parts that are unclear or things you think should be added to the description.

The five who do move on are up for some huge prizes: A trip to space, Milling Machine, a 3D Printer, a trip to Akihabara, and Team Skydiving. Of course we won’t know the order of the finalists or who the Grand Prize Winner is until the final judging round happens at the end of October.

Hacklet 17 – Keyboards

This week on The Hacklet we’re featuring some of the best keyboard hacks from Hackaday.io!

Hackers are really into their keyboards. Everyone has a favorite, and those favorites vary wildly. Mechanical, soft touch, ergonomic, QWERTY, DVORAK, chorded, you name it, there is a hacker, maker, or engineer who loves it, or absolutely hates it. For some, no commercial product is perfect. All is not lost though, as a custom keyboard is just a hack away!

ergo60

[Warren Janssens] gets things rolling with Ergo60, his 60 key ergonomic keyboard. [Warren’s] layout is a pair of 25 key hand clusters, each with a matching 5 key thumb cluster. This layout minimizes lateral wrist movement. With the reduced key count and stacked keys, the user’s hands never move from the home row. [Warren] rolled his own PCBs for Ergo60. A Teensy 2.0 running a fork of TMK serves as Ergo60’s controller. [Warren’s] is running Cherry Black switches and his keycaps are from Signature Plastics. [Warren] is using Ergo60 as his daily driver these days, so it’s no surprise that he’s set the “Completed Project” tag.

keycaps

Some say he needs no keyboard at all, and that his heartbeat sounds just like an IBM Model M. All we know is he’s called [Brian Benchoff]. [Brian’s] created a pair of minimalist keyboard projects. The Unhappy Hacking Keyboard takes us back to basics. After all, computers run on 1’s and 0’s, right? What more could a person need? Apparently just a space and return. Unhappy Hacking Keyboard uses an ATtiny85 with V-USB as the controller and the interface. Keys are cherry MX blues. The keycaps are [Brian’s] own Hackaday Cherry MX Keycaps printed by Shapeways.

zxkeyboardAn entire generation of hackers don’t know the joy of typing on a tiny rubber keyboard. [Alistair MacDonald] aimed to fix that, so he turned an old computer into a keyboard with his ZX Keyboard. [Alistair] started with a broken ZX Spectrum. He gutted the original electronics and added an Ardunio Pro Mini running the V-USB library. [Alistair] directly wired the row and column I/O lines from the keyboard to his Arduino. The result is a keyboard which is the perfect size for cell phones, Raspberry Pi’s and the like.

chordkey[Servo] teaches us new ways to type with Chordy KEY, his chording keyboard project. Chordy Key is meant to be used in the left hand. Five finger buttons and three thumb buttons are all that is needed to chord out 64 different letters and symbols. [Servo] utilized an ATmega32U4 powered Sparkfun pro micro to control his keyboard. Chordy Key is a proof of concept, but with [Servos’s] use of 3D printed parts, Chordy Key looks like it’s ready for your next wearable computing project!

chord2[jmptable] is also working on a chorded keyboard design. Chord Keyboard uses only 7 keys to send the entire ASCII character set and a few control combinations. [jmptable] used an ATmega328P as his processor. Chord keyboard isn’t wired though. An RN-42-HID module provides bluetooth connectivity to the world.

[jmptable] has provided an amazing amount of detail on his research, including one of his goals of adding a chorded keyboard to the Gameboy Advance. They keyboard itself would be mounted on the spine of a game cartridge. We would love to see that idea come to fruition, [Servo]!

 

mightyFinally we have [Gertlex], who just wanted a scroll wheel embedded in his keyboard. He got there with the help of an Apple Mighty Mouse. Keyboard with Apple Mouse Scroll Ball is one of those hacks that looks like it original equipment. [Gertlex] took a drill to a Targus slim USB keyboard, putting a small hole right between the ESC and F1 keys. He fit the scroll ball from his Apple Mighty Mouse in the hole. Electronics are as simple as plugging the mouse and keyboard into the same USB hub. The only downside to the design is that [Gertlex’s] keyboard doesn’t recognize fast enough to send key presses during the boot process.

That’s just about enough keystrokes for this episode of The Hacklet. As always, see you next week. Same hack time, same hack channel, bringing you the best of Hackaday.io!

Update – check our our keyboard list right here!

We’re at Maker Faire Atlanta, Oct 4-5

If you live in the southeastern US, mark your calenders for next weekend—October 4th and 5th—and head out to the fourth annual Maker Faire Atlanta in downtown Decatur, GA. You can find a complete list of participants here.

I’ll be around all weekend to talk to makers about their projects and to hand out some Hackaday stickers. As [Brian] said with the HaD crew at the NY Faire, don’t be afraid to introduce yourself if you see me walking around or lurking at the Hackyard booth. See you there!