Raspberry Jam (RJAM) Universal Digitizer



All models of Raspberry Shake, including the RS1D, RS3D, RS4D, RBOOM, RS&BOOM and RJAM use the same software. Sections of the Quick Start Guide have been tailored to each product but the overall manual applies to them all. Other specific manual sections, like this one, have been created to address issues specific to the individual products.

Technical Specifications Documents

Raspberry Jam Universal Digitizer (RJAM) Technical Specifications Sheet


Unlike other Shake products, the RJAM has no long period extension (from 4.5 Hz to ~2 seconds) as this would be undesirable for and incompatible with active sensors.

For details on the RJAM’s instrument response, see: Raspberry Shake RJAM

Design and Customization


The RJAM was discontinued in late 2021.

The RJAM digitizer was designed to work with most seismic sensors and supports 3-channels of single-ended and differential-ended signal inputs, passive and active sensors. Though, with single-ended inputs, one looses half the dynamic range.

Through-hole mountings are provided for resistors and capacitors to make it easy for electronics engineers and power users/ Do-It-Yourselfers to swap out components. The system is highly customizable for any sensor that has an output between +/-2.5 Volt absolute referenced to ground (also called 10 Volt differential) to +/-10 Volt absolute referenced to ground (also called 40 Volt differential).


The RJAM board is ESD sensitive, and ESD precautions must be taken when soldering components and hooking up sensors. Even small ESD events can damage the response of the RJAM and cause small signal accuracy or reliability issues, both of which are difficult to detect but cause signal distortion. Also, be sure to populate the card with the appropriate resistors and capacitors BEFORE hooking up any sensors.


Like any digitizer not inside of a metal enclosure, you should be careful with any RF sources in the area.

Channels (as labelled on PCB board):

Channel # Resistors Capacitors
1 R13,R14,R15,R16,R24 C29,C30,C31,C32
2 R22,R34,R35,R37.R38 C23,C24,C58,C59
3 R30,R52,R53,R55,R56 C33,C34,C62,C63

Component Groups:

Group Sensor Type Components
R[damp] Passive with signal output 0 - 3 Volts Damping (“Shunt”) Resistors: R22,R24,R30
R[a] Active/ Passive with signal output >3V R13,R14,R35,R37,R53,R55
R[b] Active/ Passive with signal output >3V R15,R16,R34,R38,R52,R56
C[a] Any, optional LP Filter Capacitors: C23,C29,C31,C33,C59,C63
C[b] Any, optional LP Filter Capacitors: C24,C30,C32,C34,C58,C62


Filter capacitors C[a] and C[b] are optional and can be included to provide, for example, a single-pole low-pass filter at 50 Hz. Filter capacitors were included in board design to provide some minimal protection to keep 50/60 Hz electrical noise out of the system. This low-pass filter is followed by a multiple pole digital LPF with a -3 dB frequency at ~40 Hz. The capacitor selected is best if it is a film type capacitor. If a ceramic capacitor is used, make sure it is rated at 25V or above. Do not use polarized capacitors. For film capacitors, use any type with a voltage rating above 10 volts.

Common valued capacitors to use

Value Manufacturer Part # Digikey Part # Mouser Part #
1uF MKS2B041001C00JSSD   505-MKS2B041001C00JS
0.68uF MKS2B036801C00JSSD 1928-1624-ND  
0.47 uF R82DC3470SH60J 399-11865-1-ND  
0.33uF R82DC3330AA60J 399-5906-ND  
0.22uF R82DC3220AA60J 399-9686-ND  
0.1uF R82DC3100DQ50J 399-5444-1-ND  


Passive Sensors

Examples of passive sensors that RJAM is compatible with:

Manufacturer Sensor Notes
Many Geophones WARNING: We do not recommend the RJAM for small, low generator constant (e.g., 28.8 V/m/s) geophones. Use the RS1D or RS3D instead.
Kinemetrics SS-1 Ranger  
Sercel L-4C previously Mark Products
Teledyne Geotech





Active sensors

The RJAM is compatible with the following active sensors and many more:

Manufacturer Sensor Known* Differential Voltage** Notes

Model [25,25/21]

Model 50

Model 50a

Model 60/64; 60Vx

Model 60UHP


Assuming 40V pk-pk Diff. output; data sheet is inconclusive


Sensor is 44V pk-pk Diff. When used with 40V pk-pk Diff input, signal will clip at ~90% of sensor’s full-scale

36V pk-pk Diff. actual. Use 40V Diff input.

GeoSIG AC-23 20V pk-pk Diff.




S-13 and other passive sensors


Assuming 40 V differential output

Assuming 40 V differential output

See previous table


[3,5T,6,6T,40] Series





Episensor [2,ES-T,ES-U2]

HypoSensors (FBA ES-DH)


SBEPI (202)



See above “Recommended component values for active sensors with 10V Differential outputs - Episensor FBA ES-T specific”


See above “Recommended component values for active sensors with 10V Differential outputs - FBA23 specific”


Lennartz LE-3D[lite/5s] MKIII 40V input comes close though the dynamic range is reduced. Better would be a 30V input range.







Trillium Compact[PH,AT]

Trillium 120[Q/QA]








RefTek (Trimble)








Assume output is 40V pk-pk Diff., but would be probably better served with a 50V pk-pk Diff. input structure.

Assume output is 40V pk-pk Diff., but would be probably better served with a 50V pk-pk Diff. input structure.

Steckeisen STS[2,2.5,5A,6A] Unsure what output level actually is. Assume output is 40V pk-pk Diff., but would be probably better served with a 50V pk-pk Diff. input structure.

(*) Known = we have tested them in the lab


(**) We assume that, in the seismology world, “40V peak-to-peak differential” output means that the output voltage of each signal line is swinging +/- 10 Volts with respect to ground. We have made this example list with that definition in mind, though it seems that in the seismology world the manufacturers are not consistent with how they specify the output level. In the end, the client is responsible for researching the solution and removing ambiguity surrounding how the manufacturer of their sensor(s) define the output level.


Active sensors must be externally powered.

Special cases

FMES DIY seismograph

There is more than one configuration of the FMES circuit board out there. If you have the FMES 8.0 circuit board rev 1.7 (Bob LeDoux 12/30/2018) or equivalent, as shown here, then you might try with RJAM in the 40V-Differential configuration. Reducing the FMES output gain to 40x, by changing FMES board R25 from 4.99k to 200k, will correspondingly increase your dynamic range.

RJAM Cable diagram and connector specifications

Raspberry Jam Universal Digitizer (RJAM) Cable Diagram Sheet

The RJAM DIY solution ships with a 9-pin male connector as shown below:


The female counterpart can be purchased on Digikey:

Contacts: Digikey WM2512-ND

Connector body: Digikey 23-0050579009-ND

Hand crimp tool: Molex 0638111000 (Digikey WM9999-ND) or equivalent

The sensor inputs (Z, N, E with +, -, and Ground) are shown on the back of the board underthe 9-pin connector as seen in the image below. The image is included here for reference in case your header covers up the labels.


The RJAM turn-key solution ships with an Amphenol PT07A-12-10S female connector. In addition to the sensor and cable, you will need to provide the male counterpart to this connector. We recommend the Amphenol PT06A-12-10P(SR). These are available on Mouser and Digikey.