2 layers9.9 × 7.4 mm
2 layers28.6 × 23.5 mm
Sx-70 timer
lambdaBoost/polaroid-experiments13Accompanying files for the youtube video
- Size
- 28.6 × 23.5 mm
- Copper layers
- 2
- Thickness
- 1.6 mm
- Parts
- 9
- Nets
- 10
- Pads
- 30
- Tracks, vias
- 62, 6
- Routed
- Yes
- KiCad
- KiCad 6 (file 20211014)
- Created
- 16 Jul 2026
- Updated
- 20 Jul 2026
Overview
Sx-70 timer is an open-source printed circuit board by lambdaBoost, from the lambdaBoost/polaroid-experiments repository on GitHub. It is a 2-layer board of 28.6 × 23.5 mm with 9 parts on 10 nets, routed with 62 tracks and 6 vias.
It is built around the NE555P. Its parts include 3 connectors, 2 switches, 1 capacitor, 1 resistor and 1 IC.
Main components
1README
README.mdpolaroid-experiments
This repo contains both files referred to in the youtube video here and contains notes on my ongoing attempts to improve DIY peel apart film recipes.
Peel apart film
The recipe is given in the video and may also be found at Alec Myers website.
My notes to date are:
- An ISO of 150 with 0.5ml of developing fluid and 60-90sec of development time seems to work best.
- The main issue now is getting whites to stay white. I tried different alkalinities but this doesn't make a difference.
- Using side rails shows promise. It led to a very well developed negative. This is because more developer is available - it isn't all just smooshed hard between the film and paper.
- Side rails will absolutely require a proper shaped metal roller as on the camera itself. I will try modifying my setup for this.
- I also need to try better quality and lighter waterproof paper.
- This will all be much easier on a roll film camera.
My attempts at coloring these images with additive screens will also be documented here in due course.
SX-70 timer
All the pcb schematics and raw gerber files you need to build this are in the respective folder. You'll need to make 2 pins to solder onto the board which will be inserted into the camera. I machined mine from brass, but 1.5mm wire will probably be fine.
SX-70 shaft coupler
This one is a bit trickier to manufacture since it requires a small lathe and milling machine. I am fortunate enough to have an Emco Unimat. I would recommend against 3d printing this - it needs to be very strong, so I used mild steel.
SX-70 ISO selecter board
This is a tiny pcb with just a switch and 2 smd capacitors. It is quite self expnalatory in the video, but it does require some skill and care to fit to the camera - take your time.
Testing
I test everything with a flat lithium battery inserted into a film cartridge. It supplies a stable 6v voltage through a little step up converter board. It can''t supply the same current as the original Polaroid batteries but it's enough to cycle everything.
Parts
9| Qty | Value | Footprint | References |
|---|---|---|---|
| 3 | Conn_01x02_Male | Connector_PinHeader_2.54mm:PinHeader_1x02_P2.54mm_Vertical | J1, J2, J3 |
| 1 | 1N4004 | Diode_THT:D_DO-41_SOD81_P10.16mm_Horizontal | D1 |
| 1 | C | Capacitor_THT:C_Radial_D6.3mm_H7.0mm_P2.50mm | C1 |
| 1 | NE555P | Package_DIP:DIP-8_W7.62mm | U1 |
| 1 | R | Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal | R1 |
| 1 | SILxx-1Axx-71x | Relay_THT:Relay_SPST_StandexMeder_SIL_Form1A | K1 |
| 1 | SW_DPDT_x2 | Button_Switch_THT:SW_CuK_JS202011AQN_DPDT_Angled | SW1 |
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Questions
How big is the Sx-70 timer PCB?
It measures 28.6 × 23.5 mm and has 2 copper layers, 1.6 mm thick.
What parts does the Sx-70 timer use?
9 parts, built around the NE555P. 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 Sx-70 timer KiCad files?
From the lambdaBoost/polaroid-experiments repository on GitHub, at the commit this page was made from: the board is sx-70-timer/sx-70_timer.kicad_pcb and its schematic sx-70-iso-selector/capacitor_switch.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the Sx-70 timer design in my own project?
Its repository states no licence, so its author keeps all rights: ask lambdaBoost before reusing the design.