I have also been working on the new expansion board pictured bellow. The Expansion Board was created to help you create bigger custom displays for the Spectrum Analyzer. The Expansion Board works by switching the signals from the spectrum analyzer with the help of high current MOSFET transistors thus giving you the possibility to output higher voltages and currents for your custom setup. You can read more about it on the forum.

There is also a new assembly guide for the audio spectrum analyzer V2.1 that will be helpful to those that get the kit unassembled.

Miguel writes :

The analyzer has become my best travel companion. It’s very discrete: everyone think you are playing with a mobile phone!. You can see in a moment what are the used frecuencies / channels at your location. One of the most interesting things if to carry it in the pocket in exposure mode and walk sometime in your neighborhood. In this way you can find easily what are the free frecuencies or channels. With the time, I learned how to distinguish between different device

Mobile 2.4 GHz Spectrum Analyzer: [via HackADay]

I’ll post some of the most important features and specifications here:

Dimensions:

• motherboard: 81×88 mm.
• matrix: 236×72 mm.

Power:

• 7,5 V 1 A DC (the maximum current draw is 600 mA).
• power is supplied to the board trough a 2,1 mm DC power connector.
• you can get this type of adapter from Youritronics shop.

Input signal:

• signal level 200 mV
• Audio input is supplied to the board trough 2 x RCA connectors.
• you can get this type of cable from Youritronics shop.

Features:

• 20×20 led bargraph display (red or green).
• 9 display modes selectable trough button 2 present on the display board.
• on/off (standby) control selectable trough button 1 present on the display board.
• ISP (in system programming, if you have an AVR programmer that supports this feature, you can update the firmwire if new version is released)

First units were shipped,  and I’m curious about what you think related to the project so visit the Youritronics forum and share some of your thoughts also if you have any questions you can ask them there.

You can now chose between 9 display modes and you have on/off(standby) control, My favorite is the first mode

As you can see there are now 4 displaying modes, and on/off control trough two pushbuttons that sit next to the LED’s. In this version I used a cable to connect the two boards, but the boards can also be connected one on top of each other.

I’ve checked some shipping rates for united states and here is what I got:

Romania to USA, 1 kg:

UPS Express Saver 60 USD 1-5 business days
UPS expedited 62 USD – 2-5 Business Days
DHL – something like 110 USD with 2 days delivery time
Express Mail Service 41 USD probably 10 days
FedEx -  117 USD 2 business days

At the moment it seems that UPS, DHL and FedEx require proforma invoice for the product. Because I’m not a registered company I have no means to provide that so I’ll have to find a way around this problem.

later edit: The solution is Express Mail Service which is the cheapest and I can send the item as a gift thus avoiding any other papers. Delivery time to US usually under 10 days

here are some pictures:

The movie shows v1.1 of the firmwire in action. Tomorow I’ll be ordering the pcbs and parts.. The final version will use bargraph LED’s for the display and it will be composed from 2 boards, the motherbord containing most of the parts and the LED board containing only the bargraphs.

In response to the high interest shown by the readers on a spectrum analyzer posted here I decided to make a new design, that will be available in shop as a kit. The movie shows just a stage in the developing process, where the filters were being tuned. The final design will be powered by an atmega64 and will have 20 bands with 20 LED’s on each band.

I am now searching for a pcb manufacturer to get a good price on manufacturing the boards, then it will all be ready.. stay tuned.

Audio spectrum analyzers have always been cool either in Winamp on your computer, or in a sound system that features it. Now you have the option of building it and including it into your soundsystem. In fact i think it would look very professional if you place it inside a nice case.

The real-time system computes the distribution of the audio signal energy to 20 specific frequency bands and displays it on a 20 × 20 LED display. The PIC30F6012A was choose to control this circuit  because of its numerous functions needed in this project.

LED Bar Audio Spectrum Analyzer: [Download Project] – [View Project PDF]