As mentioned in the previous blog entry, the initial prototype is built & working, I was able to walk around my house (slowly) with my eyes closed just using this device! But it can definitely be improved fairly easily. I'm quite busy at the moment so I thought I'll just list the next steps needed in case I don't have enough time to work on them for a while:

1. Reduce the amount of IR light creeping in between the IR emitter and IR receiver. Commercial IR sender-receiver pairs are separated by several centimetres and have thick black plastic and/or metal, to block all the IR light. Whereas in my current prototype I was aiming to eventually fit 2 IR emitter-receiver pairs onto a small piece of strip board to reduce space so I put them 1mm apart, and it turns out my thin pieces of black plastic tubing (pulled off an old VGA cable) aren't blocking all the IR light. Also, I realized that even if the IR emitter and receiver say they are focused within 30 degrees of the front, some IR light still happens even at 90 degrees and lots of IR light still happens at 180 degrees (ie: an LED is visible from both the front and back), but I don't currently have any light shielding at the back of the LEDs! So I need to block the IR light at the back of the IR emitter and receiver LEDs too. Once the amount of IR light crosstalk noise between the IR emitter and receiver is reduced, it should reduce the signal noise, allowing me to detect further distances since the "Signal-to-Noise Ratio" would be a lot better.
2. Modify the code to detect further distances. Currently it detects upto roughly 50 or 60cm, any further becomes too noisy, but once I've reduced the crosstalk noise mentioned above, I'd like to detect in the 80cm - 1m range to be more useful.
3. Build a 3D printed case, so it looks more professional and isn't as easy to damage by touch or water! I came up with an idea of building the case in 2 parts with a hinge near the middle, so it will bend around the contour of the user's hand whether they have small or large hands, and by putting the battery & charger in one part, it would potentially allow someone to own multiple battery parts that can be recharged individually off multiple USB ports, giving the user a whole set of charged batteries they can bring on a long trip.
4. Test the battery life. I don't know if my LiPo batteries are really 240mAh or they're just claiming to be (since cheap batteries from China often do have exaggerated ratings), and I haven't measured the average power draw of the device at different states (measuring IR but not vibrating, measuring IR and vibrating at full strength) to calculate the roughly average battery life cycle.
5. Let some real blind people use the device and get their feedback!
6. Modify the code so it sends coded pulses, to reduce the interference from sunlight and indoor lighting.