

DigiKit Tennis
Replica of a Pong game as part of a Digital Electronics kit
- Size
- 110.3 × 53.3 mm
- Copper layers
- 2
- Thickness
- 1.6 mm
- Parts
- 40
- Nets
- 45
- Pads
- 169
- Tracks, vias
- 440, 13
- Pours
- 1
- Routed
- Yes
- KiCad
- KiCad 8.0 (file 20240108)
- Created
- 24 Jun 2024
- Updated
- 3 Oct 2024
Overview
DigiKit Tennis is an open-source printed circuit board by RetroStack, from the RetroStack/BitStack-DigiKit-Tennis repository on GitHub, published under the MIT licence. It is a 2-layer board of 110.3 × 53.3 mm with 40 parts on 45 nets, routed with 440 tracks and 13 vias.
It is built around the 74LS00SC, 74LS194PC and 74LS10PC. Its parts include 10 capacitors, 10 diodes, 6 ICs, 6 switches and 5 resistors.
Main components
374LS00SC
-0℃~+70℃ 15ns@5V,50pF 2 2.7V 2V 4 4.75V~5.25V 400uA 500mV 74LS 800mV 8mA NAND Gate - Logic Gates ROHSTexas InstrumentsLogic Gates74LS194PC
-0.4mA 0℃~+70℃ 25MHz 35ns@5V,50pF 4 4.75V~5.25V 74LS 8mA Asynchronous clear function、Asynchronous parallel load function、Supports forward and reverse shift - Shift RegistersTexas InstrumentsShift Registers74LS10PC
PDIP-140℃~+70℃ 3 3.3mA 4.75V~5.25V 74LS Series NAND Gate PDIP-14 Logic GatesonsemiLogic Gates
README
README.mdDigiKit Tennis Replica
While watching my regular YouTube channels, I saw a digital electronics kit from the 70s called Tennis from the company DigiKit, shown on the Tech Time Traveller. This is a neat little board with a fun game that looks useful for beginners to learn digital electronics. The provided schematic had a lot of bugs and was very incorrect.
I spent some time reverse engineering it from screenshots of the YouTube video, and the result is this board.

Latest Files
In the "Latest" folder, you'll find the most up-to-date design files, including:
- Gerber files suitable for popular online PCB manufacturers like PCBWay and JLCPCB. Most manufacturers should be fine with either.
- A Bill of Materials (BOM) in both CSV and PDF formats.
- The full schematics of the board.
How to Play
This is a simple game of Pong where the lights in the center of the board are used to indicate the path of the "ball." The goal of the game is to hit the ball back to the other player. When the player on the receiving end misses the ball, a point is given to the one sending it. The counting needs to be done independently and is not done on the board.
How to set it up?
- The first option to set is the toggle switch, which defines the speed of the ball. It should remain the same for the duration of the game.
- Next, select who should serve the first ball. Switch the "Serve" slide switch to the side of the player who should serve. Then, press any "Reset" button. If the green light is not on the correct side of the person serving, switch it by pressing the "Shot" button from the other side. This will toggle the light.
Play
When everything is set up, the serving player should press the "Shot" button on their side. (A red light and a green light should be lit on the same side!) As soon as "Shot" is pressed, a simulated "ball" is animated across the lights in the center. When the last light is reached, the other player needs to return it by pressing "Shot" in time on their side.
Implementation
The replica has been implemented using KiCAD 8. The KiCAD project files are included in this repository.

Bill of Materials (BOM)
Below is a list of materials needed to assemble the PCB.

| Reference | Qty | Description | Footprint | Datasheet |
|---|---|---|---|---|
| C1,C4 | 2 | 2nF | Capacitor_THT:C_Disc_D5.1mm_W3.2mm_P5.00mm | |
| C2,C3 | 2 | 33uF | Capacitor_THT:CP_Radial_D5.0mm_P2.00mm | |
| C5,C6,C7,C8,C9,C10 | 6 | 0.1uF | Capacitor_THT:C_Disc_D5.1mm_W3.2mm_P5.00mm | |
| D1,D10 | 2 | Green | LED_THT:LED_D5.0mm | |
| D2,D3,D4,D5,D6,D7,D8,D9 | 8 | Red | LED_THT:LED_D5.0mm | |
| J1 | 1 | Barrel_Jack_Switch | Connector_BarrelJack:BarrelJack_Horizontal | |
| R1,R2,RN1 | 2 | 150 | Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P10.16mm_Horizontal | |
| RN1 | 1 | 150 | 8 Resistors; 9 pins | |
| R3,R4 | 2 | 1k | Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P10.16mm_Horizontal | |
| R5 | 1 | 4.7k | Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P10.16mm_Horizontal | |
| SW1 | 1 | Player A | RetroStackLibrary:SW_SPST_Push | |
| SW2 | 1 | Reset A | RetroStackLibrary:SW_SPST_Push | |
| SW3 | 1 | Serve | RetroStackLibrary:SW_DPDT_Slide_RightAngle | |
| SW4 | 1 | Speed | RetroStackLibrary:SW_SPDT_Toggle | |
| SW5 | 1 | Reset B | RetroStackLibrary:SW_SPST_Push | |
| SW6 | 1 | Player B | RetroStackLibrary:SW_SPST_Push | |
| U1,U3,U4 | 3 | 74LS00 | Package_DIP:DIP-14_W7.62mm | http://www.ti.com/lit/gpn/sn74ls00 |
| U2 | 1 | 74LS10 | Package_DIP:DIP-14_W7.62mm | http://www.ti.com/lit/gpn/sn74LS10 |
| U5,U6 | 2 | 74LS194 | Package_DIP:DIP-16_W7.62mm | http://www.ti.com/lit/gpn/sn74LS194 |
RetroStack Libraries
To work with this KiCAD project, you'll need the RetroStack libraries for KiCAD. Please follow this link to access and install these libraries.
Support this Project
RetroStack is passionate about exploring and preserving the legacy of older computer systems. BitStack is a sub-project of RetroStack, focusing on education in digital electronics. My work involves creating detailed documentation and videos to share the knowledge. I am also dedicated to reviving these classic systems by reimplementing them and offering replacement parts at no cost. If you're keen on supporting this unique project, I invite you to visit my Patreon page. Your support would be immensely valuable and greatly appreciated!
License
This project is licensed under the MIT License - see the LICENSE file for details.
Parts
40| Qty | Value | Footprint | References |
|---|---|---|---|
| 8 | Red | LED_THT:LED_D5.0mm | D2, D3, D4, D5, D6, D7, D8, D9 |
| 6 | 0.1uF | Capacitor_THT:C_Disc_D5.1mm_W3.2mm_P5.00mm | C5, C6, C7, C8, C9, C10 |
| 3 | 74LS00 | Package_DIP:DIP-14_W7.62mm | U1, U3, U4 |
| 2 | 150 | Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P10.16mm_Horizontal | R1, R2 |
| 2 | 1k | Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P10.16mm_Horizontal | R3, R4 |
| 2 | 2nF | Capacitor_THT:C_Disc_D5.1mm_W3.2mm_P5.00mm | C1, C4 |
| 2 | 33uF | Capacitor_THT:CP_Radial_D5.0mm_P2.00mm | C2, C3 |
| 2 | 74LS194 | Package_DIP:DIP-16_W7.62mm | U5, U6 |
| 2 | Green | LED_THT:LED_D5.0mm | D1, D10 |
| 1 | 150 | Resistor_THT:R_Array_SIP9 | RN1 |
| 1 | 4.7k | Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P10.16mm_Horizontal | R5 |
| 1 | 74LS10 | Package_DIP:DIP-14_W7.62mm | U2 |
| 1 | Barrel_Jack_Switch | Connector_BarrelJack:BarrelJack_Horizontal | J1 |
| 1 | Player A | RetroStackLibrary:SW_SPST_Push | SW1 |
| 1 | Player B | RetroStackLibrary:SW_SPST_Push | SW6 |
| 1 | Reset A | RetroStackLibrary:SW_SPST_Push | SW2 |
| 1 | Reset B | RetroStackLibrary:SW_SPST_Push | SW5 |
| 1 | Serve | RetroStackLibrary:SW_DPDT_Slide_RightAngle | SW3 |
| 1 | Speed | RetroStackLibrary:SW_SPDT_Toggle | SW4 |
The 39 most common of 40 parts.
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Questions
How big is the DigiKit Tennis PCB?
It measures 110.3 × 53.3 mm and has 2 copper layers, 1.6 mm thick.
What parts does the DigiKit Tennis use?
40 parts, built around the 74LS00SC, 74LS194PC and 74LS10PC. The full list of its parts is on this page, with links to each part's symbol and footprint where PCBKit's library has them.
Where can I download the DigiKit Tennis KiCad files?
From the RetroStack/BitStack-DigiKit-Tennis repository on GitHub, at the commit this page was made from: the board is KiCAD/DigiKit_Tennis.kicad_pcb and its schematic KiCAD/DigiKit_Tennis.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the DigiKit Tennis design in my own project?
Its repository publishes it under the MIT licence: you may reuse it on that licence's terms (keep the author's notice, and for a copyleft licence share your changes alike).