27/06/2019
Agenda:
- Buy USB sound cards to test whether it is possible to use the sound cards for stereo audio input using external microphones
- Sketch how we want to mount the electronics on the tank chassis and make sure that weight is balanced
Tasks Accomplished:
- Preliminary research on alternatives to input stereo audio (including using audio splitter and another rpi module)
- Mounted the electronic parts on the chassis
- 3D printed modified and improved design of the rotatable turntable
- Tried to test the tank (so that it can move independently without being connected to any plugs) by connecting the tank to a high-power battery)
Yes it is finally shopping time! Some of us went to Challenger to buy USB sound cards (audio adapter) to test whether it is possible to use the sound cards for stereo audio input. Beforehand, we discussed with our mentor and decided that there are two possible solutions to the audio problem. One is to buy a USB stereo mic adapter than we would only need to plug the mic into the stereo mic adapter and then to the rpi. However, it is a difficult task by itself to find a stereo mic adapter that allows stereo input from microphone (most adapters only allow for stereo output into your earpiece or headphone). The second option would be to buy two USB mono mic adapters where we will need to either buy an audio splitter to split the stereo mic 3.5mm jack into 2 mono USB audio adapter then to rpi. The second option is evidently tougher but would be necessary if we cannot find sound cards/ mic adapters which work.
After going back to the lab, we tested the sound cards and they did not work as they only allowed for mono input and stereo output (these specifications were not written on the product so we had to try out luck) but we still use these adapters and modify them as in the second option to make the binaural recording work. More work but here we go. 💩
Also, we tried testing the tank to see whether it can move independently while being powered by a battery that is mounted on it. Tony offered us a high-power battery that is usually used for drones. Due to high power involved, it involves certain risks and we had to solder red and black wires to the connecting adapter and use a heat shrink to make sure that all parts of the wires and adapters are insulated (no exposed metal parts on the adapter or the wires that can cause electrocution).
Above is an image of a preliminary look into how the tank looks like with all the parts and electronics mounted on the platforms (for now we only used double-sided tapes and cable wires to tie the parts to the platforms because we have not arranged the parts on the robot and settled where exactly we want to put the parts – we have to account for the weight and how much the tank will tilt according to how much weight we placed on which side of the platform).
However, we faced the problem of not being able to access the transceivers on the tank from the user’s end and we could not get the reason behind the failure. (The next day, we then realise it is because we forgot to disconnect from the NTU Secure WIFI which had resulted in the aforementioned issue).
The lab is really our go-to place almost every day of the week… hopefully our efforts will all pay off at the end of the day! 🌞🌞🌞