Work and Projects

Miles Grist


For my final year project at Imperial College London, I developed a small wearable bio-potential acquisition system.

The system leverages NFC from a mobile phone for both power and data transmission. 
It shows potential for use in at-home medical monitoring and digital health.

Knowledge gained:
- KiCad PCB design
- KiCad scripting in Python
- Analogue instrumentation
- Analogue filtering
- NFC coil design and simulation
- Digital signal processing
- TinyAVR embedded development
- Native Android development

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MuscleTap


In my spare time I have been designing small RGB LED projects for various reasons.

One is an artistic present for my cousin that consists of a 3D-printed model and a PCB with 20 addressable LEDs.
The model was created in Fusion360 to portray the gravity gun from Half-Life holding a tiger head (his favourite animal).

Another project is designed to mount to the front of my recently acquired spectacles. 
This should be finished soon and will make street skating in London more enjoyable at night.
Using an M5Stack Atom, it will feature Bluetooth control of the LEDs via an Android application (video to come soon).

Knowledge gained:
- KiCad PCB design

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Fun with LEDs


Working with two other engineers, I designed an inductive position sensor.
This sensor uses eddy currents induced in a rectangular metal target to sense the position of the target relative to a "stretched coil".
Such a coil is designed to have a varying field strength along the length of the coil.
By forming a resonant circuit with the coil, one can measure the resonant frequency and observe the changing inductance, as the target moves along the coil.
The final inductance value is read from the sensor over a USB cable to a laptop PC and mapped against a piece-wise linear calibration table to retrieve a position value.

Design achievements:
- 50um resolution
- 80mm linear input range
- Negligible sensor drift
- Absolute position measurement

Knowledge gained:
- Coil design
- Simulation with FastHenry2
- Hardware testing

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Inductive Sensor


For a course in Full Custom Integrated Circuit Design, I researched the design of clocked comparators in CMOS technology.
The comparator takes a differential analogue input and produces a digital output that results from the comparison of the inputs.
The design focused on achieving the highest possible clock frequency, without intolerable trade-off of other values of merit, such as input referred offset voltage.

A final design was produced in Cadence Virtuoso and simulated.

Design achievements:
- 6GHz maximum clock frequency
- 60ps Clk to Q delay
- 1.5mW power dissipation
- 128 square micrometer layout

Knowledge gained:
- VLSS literature review technique
- Candence Virtuoso design and simulation
- Non-idealities of mixed signal CMOS design

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Clocked Comparator


During my time at TTP, I worked as an electrical and electronic engineering consultant on many high value and interesting projects.

The breadth of projects was inspiring and introduced me to many new areas that were previously unknown to me.
I particularly enjoyed learning about hazard analysis from experienced engineers and working on safety critical electronic designs in the medical industry.

Activities were not limited to purely technical engineering tasks. 
On multiple occassions I was required to present complex ideas and specialist knowledge to clients in formal meetings.
Additionally, I organised and headed liasons with external suppliers and organisations to discuss how they could benefit ongoing projects or provide critical information.
This was a highlight of the experience.

Knowledge gained:
- Embedded software development
- Medical device design considerations
- PCB design and bring-up
- Formal presentation skills
- EMC testing procedures
- Hazard analysis for medical electronics
- Market research
- Patent searches

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TTP Internship


Modern desktop computers require a high power rated supply that can provide multiple voltage rails.

As part of the Power Electronics course, I designed the principle subsystems for an ATX power supply, with +-12V, +-5V and 3.3V rails.

A hardware version was not produced, but extensive simulations were done in LTSpice.

Knowledge gained:
- Power factor correction 
- Flyback converter design
- Voltage standby systems
- Conducted emissions

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ATX power supply design + simulation


We've all had too much fun spamming different sounds on the keyboards in music class at school.
For the Embedded Systems module, I wrote real-time firmware for a digital synthesiser, running on an STM32.

Working with low-level hardware features of the MCU, up to handling FreeRTOS processes, this project taught many core concepts of embedded systems.
Using the DMA to transfer audio samples from a buffer in RAM, interrupt frequency was reduced. Careful task priority, based on task interval, ensured 
real-time control of the audio and reading of the inputs.

Knowledge gained:
- Embedded systems design
- MCU internal hardware
- Critical instant anaylsis of real-time systems
- Safe handling of shared data in multi-threaded systems

Check out some of the sounds it can make by perusing this video!

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STM32 digital synthesiser


Manipulator robots are now widely used in many industrial applications.
There exists many toolchains for interfacing with standard robot arms, such as Universal Robots, so the underlaying models and control are often overlooked.

I took the opportunity to take a new module at Imperial College London, covering the basics of kinematics modelling and fundamental topics in the world of robotics.

During the course, we applied our new knowledge by writing Matlab programs to control an OpenManipulatorX at the servo level.

Check out some of the tasks the arm was able to perform!
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Modelling a robotic manipulator


High level figure skaters undergo extreme forces, when performing jumps and complex manoeuvres on ice.

There are no mainstream commercial wearable devices specifically for monitoring skating training and performance.

We designed an IoT sensing device for mounting to the side of a figure skater's boot. It allows the detection of angular velocity (gyroscope)
and impact forces (two force sensitive resistors) during training.

The initial prototype only provides rudimentary analysis of jump performance, by displaying parameters such as air-time and peak angular velocity to the user
on a training dashboard webpage. However, there is good scope for future development to include AI-based performance analysis and various modes of performance tracking.

Knowledge gained:
- Force sensitive resistor interfacing
- Python development
- MQTT protocol for IoT devices
- Commercial product considerations for IoT devices

Team members:
- Alexander Limonov
- Matei Tanase
- Nikolay Miladinov

See below for a video of the device in action!

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Skating