Spectrum Analyzer Wedged Into A Cellphone

[Miguel A. Vallejo] wanted a portable spectrum analyzer for the 2.4GHz ISM band. No problem, there’s modules for that are easy to interface with a microcontroller and LCD screen. But carrying around a black project box doesn’t exactly scream ‘cool’ so he fit his spectrum analyzer inside of a cell phone. This made a lot of things easier for him; he already had a few old phones, he was able to use both the original battery and the original LCD screen, and a lot of the mounting work is already done for you. The only challenge was to fit his custom circuitry inside. By hacking off part of the CYWM6935 module and cutting some protoboard in the same shape as the original PCB he managed to get everything into this tiny portable package. Now he’s looking for a way to incorporate a charger, and an on/off switch.

If you don’t have an old cell phone sitting around you can try building a spectrum analyzer that uses a character display. But we’d suggest hitting up your friends for their old cellphones.  The screens are used in all kinds of fun projects.

21 thoughts on “Spectrum Analyzer Wedged Into A Cellphone

  1. Miguel –
    You might want to check with Dallas Semiconductor. They have a variety of charge controller chips for li-ion and lipo cells. You might have to work with surface mount chips to use them. They usually have reference schematics in their datasheets, and are fairly hobbiest friendly with their sample policies.

  2. I find this rather impressive, that’s a pretty small package to put perf board in. Also notable is that wireless module is capable of ~60 kbit communication with another module (although he did cut the TX antenna off) so this device could easily be modified to do all sorts of stuff.

  3. LOL my favorite part “But carrying around a black project box doesn’t exactly scream ‘cool’”. Carrying around a spectrum analyzer over all doesn’t scream cool, never the less what its enclosed in.

    But, overall very impressive project.

  4. 10 out of 10 for ingenuity.
    Who’d have thought a >10 year old phone would be that useful?
    btw I acquired three new 3310 screens from Sparkfun on my last order, but they can be had from any old broken phone even if it has minor water damage.

    watch out for the elastomer variety, as they are a pain to connect to. i recommend keeping the display front panel intact and custom building an adaptor using shapelock + a section from a calculator pcb to reduce strain on the delicate springs.

  5. Great work! I’d love to see it mass produced for those of us who don’t need it hidden in a cell phone at an affordable price like this pocket frequency counter.

    (btw, I have no affiliation whatsoever with that shop, that counter is sold by a dozen ebay shops at least and that one was the first coming up in my search.)

  6. coolest hack i’ve seen in a while. doesnt seem too hard to put in a small lithium-ion pack and use the factory charger& plug. but idk how many volts a spectrum analyzer runs on..
    idk how small they make LiFeP04 but the ones i’ve seen are too big for that. but they are for electric bikes so theygonna be big

  7. i just read the.. stuff provided.
    he is using a Nokia 3330 battery and charges it in a working phone, so all he needs is the proper charging circuit, and he is running at 3.3v and 900mah

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