Also, you can try adopting electronics & communication techniques on Biology and make it productive. For example, advancements in MRI scans (it has lots of signal processing involved) and its demerits and how can we combat them?? Insights: linear processing and its disadvantages, multiplicative noise in addition to additive noise, template matching and its demerits, affine transformations and its absurdity etc...
umm... for a seminar, you shouldn't be void of topics I guess... You can also talk about FPGAs, reconfiguration and how it helps in say construction of a transmitter/receiver in multiplexing effectively with minimum hardware... bla bla
Also, you can speak about video games... the technology and the psychology involved.. I recently came through this information that, th video games are
really addictive. This is because they are programmed so. The death and combat sequences are programmed in such a way that it increases the adrenalin pump which is essential to motivate and keep u addicted... You could speak about the electronics aspects and the medical relevance...
Remember, you should give them enough information to be awestruck that they don't start digging deeper... Speak like a politician.. (only that you know what you are speaking about!)