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4 layers98 × 75 mmPiFinder4, the printed circuit board in 3D

A plate solving telescope finder based around a Raspberry PI and RPI HQ Camera

Size
98 × 75 mm
Copper layers
4
Thickness
1.6 mm
Parts
157
Nets
245
Pads
825
Tracks, vias
1,482, 455
Pours
6
Routed
Yes
KiCad
KiCad 10.0 (file 20260206)
Created
3 Oct 2022
Updated
6 Nov 2026

Overview

PiFinder4 is an open-source printed circuit board by brickbots, from the brickbots/PiFinder repository on GitHub, published under the GPL-3.0 licence. It is a 4-layer board of 98 × 75 mm with 157 parts on 245 nets, routed with 1,482 tracks and 455 vias.

It is built around the TPS61088RHLR, RT9742CGJ5 and BNO055, with the BQ25895RTW, LTC2954ITS8-1#TRPBF and USBLC6-2SC6 among its other parts. Its parts include 50 capacitors, 41 resistors, 20 diodes, 8 ICs and 8 connectors.

Main components

11

README

README.md

PiFinder™

A plate solving telescope finder based around a Raspberry PI, imx296 camera, and custom UI 'hat'

For an overview of what the PiFinder™ is and how it came to be visit the official project website at PiFinder.io

The PiFinder™ uses the Cedar Detect and Cedar Solve libraries by smroid. Cedar Solve is licensed under Apache-2.0.

Cedar Detect is published under the Functional Source License (FSL-1.1-MIT), which permits broad non-commercial use but excludes commercial uses that compete with Cedar Detect. Because the PiFinder™ is also offered commercially, it bundles and distributes the Cedar Detect binaries under a separate license granted expressly by the copyright holder — not under the public FSL terms. The prebuilt binaries live in bin/; see bin/README.md for the full licensing details and a copy of the Cedar Detect license. Note this is distinct from the PiFinder project's own GPL-3.0 LICENSE.

Thank you to smroid for all your support of the PiFinder project!

Banner The PiFinder™ is my attempt to improve my time at my telescope. I don't get nearly enough of it and I want to enjoy it as much as possible. So after years of observing with paper charts and, later, a Nexus DSC here is what I felt I was missing:

  • Reliable telescope positioning: The Nexus DSC is great, but my scope just isn't built for solid encoder integration. The slop in the way I have to couple the encoders means poor pointing accuracy.
  • Easy setup: The Nexus DSC needs multi-star alignment to understand how the encoders map to the sky. The process is not terrible, but I'd like to avoid it.
  • Good push-to functionality: This is one place the Nexus DSC shines... if it's well aligned. The catalog system is okay, and once you select and object the screen is clear and helpful to get the telescope pointed correctly.
  • Observation logging: I like to keep track of what I see each night. I don't often sketch, just record what I saw when, with what eyepiece and some basic info about the experience. If I could do this right at the eyepiece, that'd save time.

My hope is that other people will find this combination of functionality useful, will build their own PiFinder™ and help the whole project improve by making suggestions and potentially contributing to the software. It's a pretty easy build with off the shelf parts and beginner friendly soldering.

Features

  • Zero setup: Just turn it on and point it at the sky!
  • Accurate pointing: Onboard GPS determines location and time while the camera determines where the scope is pointing. Inertial Measurement Unit tracks scope motion and updates sky position between camera solves
  • Self-contained: Includes catalog search/filtering, sky/object charting, push-to guidance and logging all via the screen and keypad on the unit.
  • Dark site friendly: Red OLED screen and soft backlit keys have wide brightness adjustment, right down to 'off'. No need for bright cell phones or tablets
  • Easy access: Can be mounted by the eyepiece just like a finder.
  • Wifi Access Point / SkySafari Integration: The PiFinder™ can act as a WIFI access point to connect your tablet or phone to sync SkySafari or other planetarium software with your scope.

Build Your Own

The PiFinder™ is fully open-source hardware and software. You can order PCB's and 3d print the case with the files in this repo and order all the parts from the parts List.

If you would like pre-assembled units, kits or other items to jump start your PiFinder™ journey, visit PiFinder.io to see what's available and place an order.

Docs

Releases and Updates

If you are using a PiFinder, I recommend you watch releases in this repo. Click the 'Watch' button up at the top right of the page, choose 'Custom' and then 'Releases' to make sure you don't miss any new features!

PiFinder™ on my Dob

If you'd like to learn more about how it works, and potentially build your own, everything you need should be here. I recommend starting with the User Manual and then checking out the build process using the links below.

Discord

Join the PiFinder™ Discord server for support with your build, usage questions, and suggestions for improvement.

Parts

157
QtyValueFootprintReferences
16LEDLED_SMD:LED_1210_3225MetricD1, D2, D3, D4, D5, D6, D7, D8, D9, D10, D11, D12, D14, D17, D18, D20
13SW_PushRSU:SW_Push_6x6mm_SMT_withhole_tightSW_MINUS1, SW_PLUS1, SW_SQUARE1, SW0, SW1, SW2, SW3, SW4, SW5, SW6, SW7, SW8, SW9
12100nFCapacitor_SMD:C_0603_1608MetricC2, C4, C8, C14, C17, C19, C22, C23, C25, C30, C34, C35
71uFCapacitor_SMD:C_0603_1608MetricC3, C11, C18, C20, C32, C40, C53
610kResistor_SMD:R_0402_1005MetricR7, R8, R11, R12, R13, R32
522uFCapacitor_SMD:C_0805_2012MetricC28, C29, C43, C44, C45
422Resistor_SMD:R_0402_1005MetricR16, R27, R28, R29
45.1kResistor_SMD:R_0402_1005MetricR18, R19, R20, R21
4MountingHoleMountingHole:MountingHole_2.5mm_Pad_ViaH1, H2, H3, H4
3100kResistor_SMD:R_0402_1005MetricR10, R15, R23
3100nfCapacitor_SMD:C_0603_1608MetricC9, C51, C55
310uFCapacitor_SMD:C_0805_2012MetricC1, C27, C33
3680Resistor_SMD:R_0402_1005MetricR5, R33, R34
210uFCapacitor_SMD:C_1206_3216MetricC6, C7
210uFCapacitor_SMD:C_0603_1608MetricC21, C48
210ufCapacitor_SMD:C_0805_2012MetricC5, C52
22.2uHInductor_SMD:L_Coilcraft_XAL4020-XXXL2, L4
222pFCapacitor_SMD:C_0402_1005MetricC12, C13
233Resistor_SMD:R_0402_1005MetricR30, R31
24.7kResistor_SMD:R_0402_1005MetricR4, R46
24.7uFCapacitor_SMD:C_1206_3216MetricC15, C16
247nFCapacitor_SMD:C_0603_1608MetricC47, C50
2DDiode_SMD:D_SOD-123D15, D16
2RT9742CGJ5Package_TO_SOT_SMD:TSOT-23-5U4, U5
2USB_C_Receptacle_USB2.0_16PConnector_USB:USB_C_Receptacle_HCTL_HC-TYPE-C-16P-01AJ2, J7
11.8MResistor_SMD:R_0402_1005MetricR25
110nFCapacitor_SMD:C_0402_1005MetricC24
111kResistor_SMD:R_0402_1005MetricR38
1120Ω@100MHzInductor_SMD:L_1206_3216MetricFB1
112kResistor_SMD:R_0402_1005MetricR14
1150k 1%Resistor_SMD:R_0402_1005MetricR39
115nfCapacitor_SMD:C_0402_1005MetricC31
1180RResistor_SMD:R_0402_1005MetricR6
1182k 1%Resistor_SMD:R_0402_1005MetricR36
11kResistor_SMD:R_0402_1005MetricR26
12.2uFCapacitor_SMD:C_0603_1608MetricC54
1220pFCapacitor_SMD:C_0402_1005MetricC10
122uHInductor_SMD_Wurth:L_Wurth_WE-LQSH-3012L1
1270k 1%Resistor_SMD:R_0402_1005MetricR40
13.09kResistor_SMD:R_0402_1005MetricR3
132.768kHzCrystal:Crystal_SMD_3215-2Pin_3.2x1.5mmY1
1330Resistor_SMD:R_0402_1005MetricR17
14.7uFCapacitor_SMD:CP_Elec_4x5.4C26
14.7uFCapacitor_SMD:C_0603_1608MetricC49
144.2kResistor_SMD:R_0402_1005MetricR9
147uFCapacitor_SMD:C_1206_3216MetricC42
149.9kResistor_SMD:R_0402_1005MetricR2
15.1Resistor_SMD:R_0402_1005MetricR35
15.6nFCapacitor_SMD:C_0603_1608MetricC46
150Resistor_SMD:R_0603_1608MetricR24
1503398-1892SD:MOLEX_503398-1892J1
156k 1%Resistor_SMD:R_0402_1005MetricR37
16.04kResistor_SMD:R_0402_1005MetricR22
173.2kResistor_SMD:R_0402_1005MetricR1
1AO3400APackage_TO_SOT_SMD:SOT-23Q2
1BNO055Package_LGA:LGA-28_5.2x3.8mm_P0.5mmU2
1BQ25895RTWPackage_DFN_QFN:Texas_RTW_WQFN-24-1EP_4x4mm_P0.5mm_EP2.7x2.7mm_ThermalViasU9
1BatteryConnector_JST:JST_PH_B2B-PH-SM4-TB_1x02-1MP_P2.00mm_VerticalJ4
1CM4102008CM4102008:MODULE_CM4102008M1
1FH12-22S-0.5SH55CSI22CONN:CONN_FH12-22S-0.5SH55_HIRJ8
1JST 6pin connector - SM06B-SRSS-TBConnector_JST:JST_SH_BM06B-SRSS-TB_1x06-1MP_P1.00mm_VerticalJ6
1LM51571RTERLM5171Q1:LM51571U8
1LOGORSU_Graphics:bblabs_logo_medG***
1LOGORSU_Graphics:bblabs_logo_smlG***
1LTC2954ITS8-1#TRPBFLTC2954:TSOT-23_TS8_LITU3
1MLT-5020RSU_Buzzers:MagneticBuzzer_HuaWha_MLT-5020BZ1
1MU-AS90R5-Way:MUAS70RSW_5WAY1
1Power_AUXConnector_PinHeader_2.54mm:PinHeader_1x02_P2.54mm_VerticalJ3
1Q_NPN_EBCRSU:PF_SOT-23-NPNQ1
1SMAJ5.0ADiode_SMD:D_SMAD19
1SS210Diode_SMD:D_SMAD21
1SW_PWRRSU:SW_Push_6x6mm_SMT_withhole_tightSW10
1TPS61088RHLRTPS61088:RHL0020AU1
1USBLC6-2SC6Package_TO_SOT_SMD:SOT-23-6U7
1~FPCCONN:TE_3-1734592-0J5

Questions

How big is the PiFinder4 PCB?

It measures 98 × 75 mm and has 4 copper layers, 1.6 mm thick.

What parts does the PiFinder4 use?

157 parts, built around the TPS61088RHLR, RT9742CGJ5, BNO055 and BQ25895RTW. 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 PiFinder4 KiCad files?

From the brickbots/PiFinder repository on GitHub, at the commit this page was made from: the board is kicad/PiFinder_rev4/PiFinder4.kicad_pcb and its schematic kicad/PiFinder_rev4/BQ25895_Power.kicad_sch. PCBKit opens the board in the browser, with nothing to install.

Can I use the PiFinder4 design in my own project?

Its repository publishes it under the GPL-3.0 licence: you may reuse it on that licence's terms (keep the author's notice, and for a copyleft licence share your changes alike).

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