DIY Smart Spin Coater

Spin coater has been a perfect tool for thin-film coating application. But the price of the spin coater is very expensive. This makes it hard for normal people of small lab scale to access the device.

I have an idea to DIY a spin coater. The spin coater is run by a high-speed brushless motor with feedback control, so the speed is precisely controlled. The sample is sucked to the spin head by the vacuum system. The spin coater can connect to the smart devices that can access browsers to assign the spin parameter such as speed, acceleration, time, and store spin profile. This way we do not need to have complicated user interfaces such as a touchscreen on the machine itself. So, the cost of the machine can be reduced.

here is what it would look like.

Components list

One of the most important things for the project is component selection. Here is the list that I used for this project along with shop links for one who wants to recreate my project.

Components	Price (Baht)
1600kv Brushless motor	244
30A Littlebee ESC	211
Vacuum pump	856
128x64 OLED display	112
Rotary encoder	41
ESP32 Microcontroller	90
120w Power supply	390
BTS7960 Motor driver	177
SD card Module	81
Power switch	14
DC connector	78
RPM sensor	117

you can choose any similar component that suits your project, there is some spec that you need to take into consideration, you can read some more details below.

DIY guide

1. Motor and Vacuum system

To make a vacuum suction system, a motor with a horror hole in the core is required to make a connection between the external vacuum pump and the substrate holder. There are only a few choices of motor in the market. I selected racerstar 2207 1600kV brushless motor. I want to spin the substrate around 3000-9000 RPM with a 12V power supply, KV of the motor should be around 250-750KV, and as far as I searched 1600KV was the lowest I got.

The motor was mounted to the 3D print part and held with four screws. The top of the motor is connected with the 3d printed substrate holder. Each part was sealed with silicone to make it air-tight. you can download 3D print files here.

2. Circuit

I used esp32 microcontroller as the brain of the device as it supports wifi functionality which will be used to connect to a custom web app later on and has a dual-core CPU which is very useful for timing control. here is the hand-drawn circuit diagram.