myWerkzeug.de › CNC.myWerkzeug.de › Templates › Circuit boards
CNC template · Circuit boards
Servo tester with NE555
Moves a hobby servo without a microcontroller: an NE555 produces 50 pulses per second whose width (about 0.9 to 1.9 ms) is set by a trimmer. Handy for testing and adjusting servos.
- Size
- 62 × 52 mm, 1.6 mm thick
- Material
- Circuit board (FR4)
- Difficulty
- Intermediate
- Milling time
- approx. 21 min
- Bits
- Engraving bit 30°, PCB drill Ø 0.8 mm, PCB drill Ø 1 mm, PCB drill Ø 1.3 mm, Corn cob router bit Ø 2 mm
- Customise
- Fixed template, freely editable once opened
Free with an account · carve with Chrome or Edge · no installation
Build instructions
Parts
| Qty | Part | Value | In layout |
|---|---|---|---|
| 1 | Resistor 0.25 W | 10 kΩ Colour bands: brown, black, orange, gold | R1 |
| 1 | Resistor 0.25 W | 270 kΩ Colour bands: red, violet, yellow, gold | R2 |
| 1 | Trimmer, vertical | 10 kΩ | P1 |
| 1 | Ceramic capacitor | 100 nF | C1 |
| 1 | Ceramic capacitor | 10 nF | C2 |
| 1 | Electrolytic capacitor Polarised: the stripe on the case is minus, the long lead is plus (square pad). | 100 µF / 16 V | C3 |
| 1 | Signal diode The band on the case is the cathode and sits on the side of the line in the layout. | 1N4148 | D1 |
| 1 | Timer IC Notch towards the mark in the layout; solder the socket first and insert the IC last. | NE555 | IC1 |
| 1 | Screw terminal 2-pin, 5.08 mm pitch | X1 | |
| 1 | Pin header, 2.54 mm pitch | 1 × 3 | X2 |
| 1 | IC socket DIP-8 |
You also need: soldering iron (about 30 W, fine tip), 0.5 to 1 mm solder with flux, side cutters and a multimeter.
Assembly
- Mill the board: isolate the copper first, then drill, and finally mill out the holes and the outline. The order is shown in the Milling panel.
- Cut through the holding tabs, deburr the edges and rub the copper bright with a scouring pad. After that, do not touch the copper side with your fingers.
- Use a magnifier and a continuity tester to look for leftover copper between neighbouring traces; cut any bridges with a craft knife.
- Insert the parts from the side without copper and solder them on the copper side. Fit low parts first: resistors and diodes, then sockets and transistors, and finally capacitors, terminals and large parts.
- Before soldering, compare the polarity with the component layout: band of the diodes, flat side of the LEDs, minus stripe of the electrolytic capacitors, notch of the ICs.
- Solder each lead for about two seconds at around 330 °C: tip on pad and lead, feed solder until it flows all round. Then clip the leads just above the joint.
- Fit D1 with the band towards the mark: the capacitor charges through D1 and discharges through R2; only this keeps the pause almost constant.
- Solder the three-pin header X2; the servo cable plugs in there later.
- Visual check: no solder bridges, no dull, balled-up joints. Remove flux residue with isopropyl alcohol and an old toothbrush.
Test and power up
- Before switching on for the first time, check with the meter that there is no short between plus and minus of the supply. Power up the first time on a bench supply with current limiting if possible.
- Press the NE555 into the socket with the notch towards the mark.
- Plug the servo onto X2: brown or black to −, red to +, orange or white to SIG.
- Turn P1 to the middle and apply 5 to 6 V to X1: the servo moves to the centre. It follows when you turn P1; if it hums at the end, do not turn P1 fully to the stop.
- Finally protect the copper side against oxidation with solder lacquer or plastic spray.
How to carve this template
- OpenOpen the template in the app and adjust size and text if you like.
- CheckLook at it in 3D, check run time and warnings.
- Set upThe carve wizard guides you through material, clamping, bit and zero point.
- CarvePress start; the app drives your Grbl router directly over USB.
