DIY Adapter for Glass and Magnetic Scales
Features
- Supports four linear axis inputs, tachometer, and a touch probe or tool setter input
- Scale inputs can be configured for use with PNP, NPN, and push/pull sensors
- Two separate onboard linear voltage regulators provide clean power supply voltages to the 5V scale rail and 3.3V logic rail
- Per-scale bypass capacitors filter out transient spikes on the power supply lines
| Scale Inputs | 4 |
|---|---|
| Tachometer Input | Yes |
| Probe/Height Setter | Yes |
| Power Supply | 7.2V DC - 9V DC |
| Current Draw | Approx. 200 mA |
| Width | 2.7" |
| Length | 2.8" |
Supported Scales
This TouchDRO adapter circuit supports a wide array of Glass and Magnetic DRO scales, as well as many standard rotary encoders that output a quadrature signal with a 5V level. This includes most, if not all, brands of budget Chinese Glass and Magnetic DRO scales, as well as the vast majority of modern brand-name DRO scales.
To ensure that your particular scales are supported, please refer to their documentation to ensure that the scales use positive 5V power supply voltage and output quadrature signal with a 5V level.
For more information about Glass and Magnetic DRO scales, refer to the pages linked below:
Circuit Schematic
Bill of Materials
| Value | Description | Qty. | Reference |
|---|---|---|---|
| MSP430G2553 | 16-Bit mixed-signal microcontroller (pre-programmed) | 1 | U1 |
| 74xx244 | SN74HC244 Octal Buffer | 1 | U1 |
| HC-05 | Bluetooth Transceiver, Slave | 1 | HC-05 |
| LM1117T-3.3 | Voltage Regulator, 3.3V 800 mA, LDO | 1 | LM1117 |
| LM1117T-5.0 | Voltage Regulator, 5.0V 800 mA, LDO | 1 | LM1117 |
| Capacitor, 100 uF | Cap. electrolytic, 100uF, 35V | 3 | C1, C2, C3 |
| Capacitor, 0.1uF | Cap. ceramic, 0.1uF 50V | 12 | C4-C15 |
| Resistor, 330 Ohm | Metal film resistor, 330 Ohm, 1/4W, 5% | 2 | R2, R3 |
| Resistor 47KOhm | Metal film resistor, 47 KOhm, 1/4W, 5% | 1 | R1 |
| Resistor Network | Resistor Network, 47KOhm, 10 Pin | 1 | RN1 |
| LED | LED, Green 3mm, 20 mA | 2 | HB, PWR |
| Pin Header | Pin Header, 4x1, 1" spacing | 5 | X,Y,Z,W, HC-05 (optional) |
| Scale Connector | D-Sub 9 Pin, Female, Panel Mount | 4 | N/A |
| Power Jack | 2.1x5.5 mm power input jack, PCB mount | 1 | Pwr |