Temasek Poly team develops speed tester to help LTA take action against illegally modified AMDs

SINGAPORE – A Temasek Polytechnic (TP) engineer and group of students have developed a speed tester for stationary active mobility devices (AMDs) that the authorities are now using to clamp down on illegally modified machines.

When the idea of building a stationary speed tester was first floated by the Land Transport Authority (LTA), Mr Venkata Rathnaiah was not convinced it could be done.

“At the beginning, we thought it might be very difficult – maybe even impossible,” said the 53-year-old senior engineer from TP’s Robotics and Automation Centre.

He initially thought it was impossible because “we didn’t have anything to follow” and had to start from scratch. Building a device that could cater to two-, three- and four-wheeled vehicles also seemed daunting.

“LTA wanted such a device, but nothing like it existed,” he said.

After two years of development, Mr Venkata and six TP students came up with a 7kg working device that can determine the top speed of a stationary AMD by lifting it up to measure the rotations of its driving wheel.

Before the device was created, LTA officers had difficulties taking action against owners of illegally modified AMDs that can travel in excess of the legal speed limit.

In Singapore, the speeds of AMDs such as e-scooters and power-assisted bicycles, or e-bikes, are capped at 25kmh. From June 1, the speed limit of personal mobility aids (PMAs) – mobility scooters and motorised wheelchairs – on public paths

will go down from

To act against a speeding AMD, officers had to catch the user in the act. But if a device was stationary, there was no way to determine its maximum speed capability on the spot.

“Modified devices which can travel at excessive speed are sometimes hidden under the guise of a registered and compliant device,” LTA told The Straits Times.

“In the past, we (could) only take action if they were observed to be physically speeding, but not when they are stationary.”

Without a way to test the top speed while the device was at rest, enforcement was limited.

Since the deployment of the TP team’s creation in November 2025, it has detected more than 100 offences and led to the impoundment of 30 non-compliant devices, LTA said on Feb 24. About 20 per cent of those impounded devices could have evaded detection without the speed measurement device.

Getting to this point was no small feat. The TP team had to design a system that can accommodate two-, three- and four-wheeled AMDs of varying sizes and configurations.

The first prototype, built in 2023, was “very, very raw”, Mr Venkata said. Made partly from 3D-printed parts, it could measure speeds of only up to 6kmh. Now, it can measure speeds of up to 60kmh.

At the heart of the device is an optical encoder – a high-precision sensor that converts the number of times the roller rotates into a speed reading in kilometres per hour.

When an AMD wheel spins against the speed measurement device’s roller, the encoder counts the rotations per minute. Using the width of the device’s roller as a constant, the team avoided having to account for the different wheel sizes of various AMDs on the market, said team member Uwaisulkarni Ahnaan, 24.

Mr Ahnaan, who worked on the coding and mathematical calculations in the later prototypes, helped improve the accuracy and reliability of the readings. He will graduate with a diploma in mechatronics in 2026 and now works at a local engineering company as an automation design engineer.

Another team member is Mr Harigovind Menon, 21, who graduated with a diploma in mechatronics in 2025 and is now a full-time national serviceman. He said the early stages of development were about getting the fundamentals right.

The team had to decide on the device’s form, the weight it needed to withstand, the materials to use, and how to ensure compatibility with different AMDs.

They also had to make sure the speed measurement device could withstand Singapore’s heat and rain, refining the design based on feedback from LTA officers using it in a field trial.

When the officers said an early version was too bulky to carry comfortably, they added a retractable handle so officers could wheel the 7kg device like cabin luggage.

The team also replaced a standard LED screen with an e-paper display – similar to those used in e-readers – to ensure readability under a bright afternoon sun.

They also made sure the device was splash-proof, and added a battery life indicator.

To ensure the readings would stand up in court, the team secured certification from the Singapore Accreditation Council. This is valid for one year, after which the device must be revalidated.

The speed measurement device itself has an estimated lifespan of at least five years, depending on usage and maintenance, said Mr Venkata.

For the students, the project offered lessons that went beyond the classroom. Mr Ahnaan and Mr Hari said they are proud to have helped build a device that will be used nationwide to keep paths safer.

“You shouldn’t think, ‘I’m just a student – my idea won’t be good enough,’” said Mr Ahnaan.

Mr Hari agreed, adding: “Be open, and don’t doubt your ideas.”