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1 Introduction
Hello and welcome to the DERCOASTER project documentation. This collaboration between der8auer and ElmorLabs is intended to introduce you to the world of electrical engineering through soldering and learning about circuitry. The package contains everything to get you started except for soldering equipment and a USB cable. We hope you will enjoy this experience and proceed to make your own electronics project at some point. If you need help with anything feel free to check out the dedicated ElmorLabs forum section or Discord.
2 Included parts
The project comes with printed circuit board (PCB) coasters, a RGB controller PCB and electrical components for soldering to it (listed separately).
| Item description | Quantity | Picture |
|---|---|---|
| DERCOASTER PCB | 5 |  |
| DERCOASTER-CONTROL PCB | 1 |  |
| DERCOASTER electrical components (Box 1-4) | 1 |  |
3 Before starting
The first thing you need to do is to identify the items in the package and their purpose. The table above lists the general included parts. A detailed list of the circuit board components is available here. Next make sure that you have the soldering equipment necessary to proceed. If you’re new to soldering check out the detailed instructions on soldering. It can also be helpful to have a DMM (digital multimeter) available for checking connections and debugging the circuit in case something isn’t working.
3.1 Required equipment
- Soldering iron
- Solder (with flux)
- Tweezer
- USB Type-C cable and USB port providing power
3.2 Useful equipment
4 Soldering the components
If you’re not familiar with soldering surface mounted devices (SMD) we recommend you to check out the video above to learn about techniques that will help you get a better result.
There is an online interactive bill of materials (BOM) available made possible by the Interactive HTML BOM plugin for KiCad. This helps greatly to find which component should be placed where without needing to download the full project files and software.
4.1 Practice
On the DERCOASTER PCB we’ve included different sized resistor footprints (positions for soldering components) together with matching resistors (in box 1) for practicing your soldering skills. They are not connected to anything else in the circuit and will not affect the functionality if they are damaged. Start with the largest size resistor (2512) and keep going down in size with increased difficulty. Even professionals will struggle with the 0201 or 01005 size! More details on footprints are available on the Components page.
4.2 DERCOASTER-CONTROL
We suggest starting with soldering the components on the DERCOASTER-CONTROL PCB that are required for the microcontroller to operate and control the LEDs. When soldering these parts start by adding some solder to one of the pads and put the part in place using a tweezer while heating the pad with solder on it. If you heat the solder for too long the flux in the solder tin may fully evaporate and you need add more tin or flux to ensure a good solder joint. After removing the soldering iron tip and the pad cools down the part should stay in place making it simple to solder the remaining pins. For best results, place the solder iron tip on both the pad and component pin and add the solder tin. The parts you need for this step are listed in the table below.
| Reference | Value | Description |
|---|---|---|
| U1 | ATtiny44A | Microcontroller |
| R1 | 10 kohm | RESETn pull-up resistor |
| R2 | 10 kohm | BUTTONn pull-up resistor |
| R4 | 100 ohm | BUTTONn filter resistor |
| R8 | 100 ohm | LED_DOUT filter resistor |
| C1 | 4.7 uF | 5V decoupling capacitor |
| C2 | 10 nF | RESETn filter capacitor |
| C3 | 10 nf | BUTTONn filter capacitor |
In order to provide power and control to the circuit the next steps are to solder the USB Type-C connector with accompanying components, power switch and push button.
| Reference | Value | Description |
|---|---|---|
| USB1 | TYPE-C 6P(073) | USB Type-C Connector |
| FB1 | 120 ohm @ 100 MHz | 5V power filter ferrite bead |
| R9 | 5.1 kohm | USB Type-C CC1/CC2 pull-down resistor |
| SW1 | MSK12C02-HB | Power slide switch |
| BUTTON1 | EVQPUA02K | Push button for LED control |
The final required step is to solder the LED chips. Please note that the marked corner on the LED indicates pin #4 and should be aligned with the hooked silkscreen line on the circuit board.
At this point you should be able to test the DERCOASTER-CONTROL PCB by connecting a USB Type-C cable and move the power switch to the ON position. If you did everything correctly, the LEDs should show a breathing effect with yellow color.
| Reference | Value | Description |
|---|---|---|
| D1-D8 | WS2812B-B/W | Addressable RGB LED |
In order to be able to connect the two circuit boards together, we need to solder the J1, J2, J3 and J4 pin headers to the DERCOASTER-CONTROL circuit board. The pin headers provide both electrical connections as well as mechanical support. Make sure to note that J1 has two additional pins in order to provide guidance when connecting the two boards together.
| Reference | Value | Description |
|---|---|---|
| J1 | Pin Header 2×5-pin 2.54 mm | Mechanical support and programming header |
| J2, J3, J4 | Pin Header 2×4-pin 2.54 mm | Electrical and mechanical support |
If you wish to use this project with a programmer (not included) in order to upload your own code it’s necessary to also the filter resistors on the data lines used for this purpose.
| Reference | Value | Description |
|---|---|---|
| R3, R5, R6, R7 | 100 ohm | Programmer data lines filter resistor |
4.3 DERCOASTER
If you’ve completed the DERCOASTER-CONTROL circuit board, continuing with the DERCOASTER circuit board will be very familiar. There are no new parts introduced here.
As on DERCOASTER-CONTROL, start by soldering the decoupling capacitor and ferrite beads. Then you can continue with the LEDs and finally the pin sockets.
| Reference | Value | Description |
|---|---|---|
| C1 | 4.7 uF | 5V decoupling capacitor |
| FB1 | 120 ohm @ 100 MHz | 5V power filter ferrite bead |
| FB2 | 120 ohm @ 100 MHz | LED data filter ferrite bead |
| D1-D12 | WS2812B-B/W | Addressable RGB LED |
| J1 | Pin Socket 2×5-pin 2.54 mm | Mechanical support |
| J2, J3, J4 | Pin Socket 2×4-pin 2.54 mm | Electrical and mechanical support |
4.4 Completion
You have now completed all the necessary steps to create your own circuit board coaster with built-in light effects. If all the steps have been completed correctly, congratulations are in order! You can use the button to change the effect. Long pressing the button will change the color. The setting will be saved and recalled when the device is powered on again.
6 Further exploration
After completing the steps to get started you may want to further explore what you can do with this project. It’s possible to write your own code and upload it to the microcontroller with an AVR compatible programmer, for example USBasp. The pinout of the J1 pin header on DERCOASTER-CONTROL is compatible with standard USBasp programmers. We encourage you to create your own DERCOASTER project and share it on Github and our forums or Discord!
The DERCOASTER firmware source code is available on Github.
