Small And Simple FM Radio

September 21, 2010 by Mike Szczys 23 Comments

[gpsKlaus] built this little FM radio (translated) based on the AR1010 IC. That chip is controlled via I2C by an ATtiny45 microcontroller. His tuning implementation relies on presetting 16 stations in the firmware and selecting them with the white potentiometer.

The FM chip came on a breakout board from SparkFun. Not bad at around $15 as it includes the crystal, some caps and a few resistors, and you don’t have to try and solder to the fine pitched pads on that minuscule package. We’re a little unsure of the features included in the part as the datasheet is lacking in detail and the reference datasheet that SparkFun includes in the description is obviously for a much more full-featured chip. Still, this would be a fun thing to play around with if you’ve grown tired of blinking LEDs.

If you don’t want to let an integrated circuit do all the heavy lifting try this post for a guide on building your own radio tuner.

Discussing Pulse-Width Modulation

September 21, 2010 by Mike Szczys 53 Comments

[Michael Kleinigger] posted a lengthy discussion on Pulse-Width Modulation that goes beyond the traditional beginner tutorial. He starts a bit of background info on PWM and a tip about using a camera to judge frequency and duty cycle of LEDs. From there it’s down the rabbit hole with some testing of power-loss versus frequency.

When you change from frequencies of 50 Hz to 1 MHz how does the parasitic power loss from switching affect the overall efficiency of the circuit? It turns out there’s a rather large amount of loss at the highest level, around 1.5 mW. The greatest balance of low power loss and elimination of flicker seems to be right in the 300-500 Hz range.

Another Approach To Power Meter Data Harvesting

September 21, 2010 by Mike Szczys 17 Comments

[Dodgy] wrote in to talk about his power meter data harvesting programs. This uses the same hardware by CurrentCost as the hack we looked at over the weekend but [Dodgy’s] implementation is different. It’s separated into two parts, the first is a webserver written in C that harvests the data and makes it available at an address on the network, the second is written in Perl to format and upload data to Google PowerMeter.

The C program serves data on a configurable port, defaulting to 3090. All of the data can be accessed in one line of code by loading http://127.0.0.1:3090, or individually with subdirectories like /watts, /time, or /tempr. From there you can do what you want with the data. The second part of [Dodgy’s] suite is a Perl script that polls the C server and sends the data to your Google account.

One thing that interests us is his comment that you should be able to compile the server side C code for an embedded device. It would be a nice energy savings to be able to upload data regularly without a PC running constantly.

Homebrew Firmware Upgrade For VCI-100 Turntable Controller

September 20, 2010 by Mike Szczys 13 Comments

We love hacks that take quality products and make them better. This enhanced firmware for the VCI-100 is a great example of that. In a similar fashion as the Behringer hack, [DaveX] reverse engineer the firmware for the device and figured out a few ways to make it better. It improves the scratch controller and slider accuracy to use 9-bit accuracy from the ADC readings, which in the stock version were being shifted down to 7-bits. There’s also a few LED tricks they call Disco Mode. They’re selling a “chip” that you need to flash the firmware but from what we can see it’s simply an RS232 converter so you might be able to figure out how to work without that part. We’ve embedded a demo of firmware version 1.4 after the break.

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Motorcycle Rear-view With In-helmet Display

September 20, 2010 by Mike Szczys 44 Comments

Want to see what’s behind you when riding your sport bike without taking your eyes off the road? They make rear view cameras for that but [Nescioqd] wanted a rear display right in his helmet (PDF). He started by mounting a rear-pointing camera on the back of the bike, powered from the 12V feed for the taillight. On the display side of things he picked up a Myvu Crystal wearable display. This is like a pair of glasses that have small LCD screens were the lenses should be. [Nescioqd] removed one lens and mounted it inside the helmet.

Since the display resides inside the helmet there is some concern about being able to see at night with a bright screen below your eyeball. [Nescioqd] actually ran into the opposite problem at first, bright sunlight makes it difficult to see the image on the LCD screen. He fixed this by picking up a dark tinted helmet visor (the easiest solution) but we’d love to see a photoresistor used to regulate the backlight level.

It would be interesting to see both screens used, with rear-view on one side and an instrument display on the other.

Audio Cabinet Refit With Modern Equipment

September 20, 2010 by Mike Szczys 16 Comments

Hard at work on making this 1960’s Fleetwood audio console usable again, [Travis] packed a lot of power into the retro case. Both the radio and turn table had stopped working but the cabinet looks great and the speakers still work. In the lower center cavity you’ll now find a full computer motherboard and replacement amplifier. A new turntable has been added with an interesting vibration-dampening shelf to support it. [Travis] built the shelf with a void in between two layers of wood which he filled with sand to help with isolation. The remote control for the amp also needed some work as the receiver is pointed to the back of the unit. To fix that a second IR receiver found a home behind the fabric for one of the speaker grates. That receiver is monitored by an ATmega168 microcontroller and signals are repeated back to an IR LED mounted near the amplifier.

Beefing Up A Cheap Drill Motor

September 20, 2010 by Mike Szczys 18 Comments

[Rob] just finished reinforcing a cheap drill motor. He picked up the tool at Harbor Freight and ditched the case. The plastic retaining ring was replaced with a thick metal washer which he machine The washer uses three bolts to attach to the mounting plate that he welded together. We’re not exactly sure what he’s got in mind as he only mentioned that this will be used with a robot. We wouldn’t mind having one of these as a bench motor but there must be hundreds of uses now that it can be attached to just about anything. It seems Harbor Freight has become popular as hacking’s raw material source. The last example we saw of this was a welding table made from a utility cart.