HardLabs

Ti-99-keyboard

JonVogel·ti-99-keyboard·pcb/ti99-kb-adapter.kicad_pcb

Ti-99-keyboard PCB layout, top view — open source ESP32 board by JonVogel
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About the Ti-99-keyboard PCB

Ti-99-keyboard is an open source ESP32 PCB design by JonVogel, published on GitHub under the MIT license. It is a 2-layer board measuring 73.5 × 90.3 mm, with 55 components from 9 distinct parts.

Its main chip is the ESP32-S3-N16R8, from the ESP32 family. By type, the board carries 32 resistors, 16 transistors, 6 connectors and 1 IC.

It belongs with the iot & wireless, keyboards and dev boards & breakouts designs in this gallery.

From the project

ESP32-S3 USB/BLE keyboard adapter for the TI-99/4A home computer

An ESP32-S3 based adapter that lets you use a modern Bluetooth (or USB) keyboard with a Texas Instruments TI-99/4A home computer.

The adapter installs inside the TI in place of the original keyboard connector and emulates the original 6×8 key matrix, translating HID reports from a BLE/USB keyboard into key presses the console's keyboard scan sees as if they came from the original keyboard. The original keyboard can optionally run in parallel.

Main components on the Ti-99-keyboard

ESP32-S3-N16R8

Ti-99-keyboard bill of materials (BOM)

55 components, 9 distinct parts — part numbers from the project's BOM.

QtyPartRefs
1
ESP32-S3-N16R8
U1
16
BSS138
Q1, Q2, Q3, Q4, Q5, Q6, Q7, Q8 +8
1
PWR_5V_IN
J9
1
TI_KBD
J10
1
PWR_TI_IN_CABLE
J13
1
PWR_TI_OUT_MB
J14
1
SPARE_PAD
J15
1
TI_KBD_PARALLEL
J20
32
10K
10k
R1, R2, R3, R4, R5, R6, R7, R8 +24

Ti-99-keyboard design files

The KiCad project lives in the JonVogel/ti-99-keyboard repository on GitHub; these links point at the commit this page was built from.

Ti-99-keyboard: common questions

What microcontroller does the Ti-99-keyboard use?

The Ti-99-keyboard is built around the ESP32-S3-N16R8, from the ESP32 family.

How big is the Ti-99-keyboard PCB?

The Ti-99-keyboard measures 73.5 × 90.3 mm, has 2 copper layers and is 1.6 mm thick.

How many components are on the Ti-99-keyboard?

55 components, from 9 distinct parts, with part numbers taken from the project's own BOM. The full bill of materials is listed on this page.

Where can I download the Ti-99-keyboard design files?

From the JonVogel/ti-99-keyboard repository on GitHub, which has the KiCad layout, the schematic and the BOM; the links under Design files point to each one.

Can I use the Ti-99-keyboard design in my own project?

Yes, under the terms of its MIT license, which JonVogel chose for the repository.

Can I test firmware for the Ti-99-keyboard without the hardware?

Yes. HardLabs builds a simulation of the board from its netlist and BOM, so you can run and debug ESP32 firmware against it before you order a PCB.

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