Having Crohn’s disease sucks.. but it has enabled me to be involved with some pretty exciting medical technology over the years and as we all know I’m all about the tech!
Back in 2018 when I was still trying to figure out what had gone so incredibly wrong with internals I was offered a chance to try capsule endoscopy, obviously I jumped at the opportunity. The big issue with traditional endoscopy / colonoscopy is that it’s quite invasive and time consuming, but worst of all not able to reach into the ‘inner depths’ of the human digestive system.
Capsule Endoscopy, quite to its name, involves a capsule containing a small camera, rf transmitter and battery. The capsule when swallowed relays images to a body worn reciever which captures the data. Pictured is mine, a Given Imaging SB3 “PillCam”, and yes it is the same one that brought me my diagnosis.
The specifications provided in the user manual provide quite an insight into the technology inclosed within:
|Dimensions||Length: 26.2mm; Diameter: 11.4mm|
|Field Of View||156°|
|Bandwidth||3.2 MHz @ 2.7 Mbps; 6.5 MHz @ 5.4 Mbps|
The PillCam is able to operate for around 8 hours on it’s tiny Silver-Oxide battery which is just about enough time to make it’s way though a human maze. Power seems to be controlled via reed switch actuated by a magnet in the top of the case, as obviously these units are solidly sealed.
As a radio ham the first thing I did when I got home was fire up the SDR to see if I could figure out what was being transmitted by the capsule as the reciever’s video display was turned off and locked to preserve battery power before I departed, sadly decoding the capured IF data into an actual image proved beyond my skills and I highly suspect there is some propriety wizardary going on it the background, But if someone want to give it a try you can find a brief IF capture here.
The operating frequency of 434.1Mhz is not terribly surprising given its right in the middle of the ISM band, although the bandwidth used (~13Mhz) does and waterfall gave me some indication that the transmitter is a simple design using Minimum Shift Keying (MSK) to convey data back to the reciever which makes sense given it’s minute power (~20nW).
For me this singular piece of technolgy is an absolute marvel, and ended up being the keystone of my diagnosis.
If there is enough interest maybe I’ll post my experience with the Pillcam in the future. You can read about my experience here