In the 1990s, there was an attempt to introduce an electronic system to control loss of contact in race walking, using a system invented and patented by Mr. Dennis Furlong (patents: EP0360930A1 and US 4956628) and based on the use of specific shoes provided with pressure sensors inserted in the sole giving electrical signals to two electronic devices included in the shoes. These devices, in turn, provided an alarm when there was a failure or loss of contact by the walker. The Furlong design allowed for a small loss of contact, called a 'flight time'. Any losses of contact greater than this threshold amount would register.
The system was examined and assessed by the IAAF but it was discarded as it had several problems due to its excessive weight and size and due to the insufficient accuracy of its operation.
Technology has progressed a long way since then and hence the revisit, taking advantage of new technological designs. A position paper was prepared in 2013 by Italian Antonio Amigo and was then widely circulated for review and comment (see http://www.vrwc.org.au/documents/2013-Electronic-System-for-loss-of-contact-control-in-Race-Walking-Antonio-Amigo.pdf).
An amount of money was made available by the IAAF to mount a pilot study for what was termed The Electronic Detection System Project to create a definitive judging system for race walking events. As of December 2016, this pilot has now moved to the design stage, with contracts signed to construct two preindustrial demonstration prototypes to detect loss of contact by race walkers. One will be used in training and another for competition. The timeline for completion of the project is 18 months.
The results of this project will then be considered by the IAAF Race Walking Committee in order to draw up a rule change proposal which would then need to be considered by the Technical Committee and approved by Council. The goal is to be able to trial a system in competitions ahead of the 2019 IAAF World Championships.
Note that this would only detect loss of contact or unacceptable flight phase times. Judges would still be required to monitor the event (in particular, the final 100m) and rule on bent knees.
I would hope that the final accepted rule change would be based on minimum flight times rather than on pure contact. It is fair to say that any new system that seeks to completely eliminate any loss of contact would force such a slowdown in races that it would effectively kill the sport. And of course, it goes without saying that the current records would need to be anulled.