0. Quick Start
New iOS 7 Compatibility Information - Microphone Permissions
If you choose to deny microphone permissions in iOS 7, Geiger Bot will unable to acquire any input. In 1.7.0, permission denied status is displayed very clearly over the main numeric display.
Here's how to undo this and get audio input back:
WARNING - Documentation Update Status (2013-09-10)
Some of this documentation is now outdated as it is difficult to find the time to maintain it all while devoting significant time to ongoing development. Especially when new development makes a documentation update obsolete again.
For complete information, please check the main page of this site and update history for additional information that may have been omitted from this page. Additionally, I have tried to document the Settings pages in-app and that information should be considered more up-to-date than this page.
If you are interested in helping maintain the documentation please email me.
Introduction
This documentation is written with the assumption you have some understanding of radiation and how it is measured. It is not a replacement for your Geiger counter's documentation, professional radiation monitoring, a health physics officer, or a doctor.
Despite the amount of documentation present here, Geiger Bot is intended to be simple and require no configuration on your part. The default settings are smart, adaptive, and generally work well, even with a microphone.
But if you want or need to do more than that, you can.
WARNING! The indicators and dose equivalent rate displayed by Geiger Bot are not a guarantee of safety. There are types of radiation that are difficult to measure with standard GM tubes (alpha, soft beta, neutron, soft x-ray, etc). The greatest risk to your health is likely from ingesting or inhaling radioisotopes, and a gross radiation background count cannot directly measure that.
It is also very difficult to detect contamination in food or drink, and is usually something done by a laboratory scintillation counter with chemically processed samples.
Graphical Guide
(note: work in progress. The new graphical guide will eventually be separated from the old reference text. I plan to translate this into Japanese and include it in the next release. The grammar style is awkward, but it helps machine translation.)
☢: > 0.5 µSv/h (elevated above
average background levels)
Dosimeter; total accumulated
dose equivalent. Saved until a
full "reset" is performed.
(Graph Scale: only active on graph display screens)
Reset: Zero, clear log file, and reset dosimeter
✉: email log file
☀: LED or screen light
Purple keys are alternate functions. Press and hold the button to use them.
ВНИМАНИЕ: > 3.5 µSv/h (much
higher than normal. Use caution.)
⌚18s↑: Current measurement time
Σ: Total counts (since last zero)
0: Total time (since last zero)
δ: Statistical error % (for current measurement time)
Display screen navigation
∅: "Zero the meter"
(reset measurement to 0)
⚙: Settings
Display unit
Auto: Up to 120s, reset to 1s when a large change is detected
All: Average of total count and total time
15s: Average of last 15s
5s: Average of last 5s
Display Screen Selection
1. Main Display
Note the position of the white-colored "dot". It indicates the current display screen. This is the navigation control.
This screen displays a moving average. You can choose the units, and the measurement time.
This number is also shown below the graph on the other display screens.
2. CPS/CPM Graph
Displays counts from last 300 seconds or 300 minutes, depending upon the graph scale selected.
For most GM tubes, any shading in the graph is an abnormally elevated level of radiation above natural background levels.
3. Audio Graph / Histogram
For troubleshooting and verifying proper operation.
Visualization of the last 5 seconds of audio input.
Red line: volume threshold
Black line: input volume level
Blue line: when a count was detected
.::.. Histogram: Displays bins of maximum volume detected during the count. This is for gamma spectroscopy. It is of no use with a Geiger counter.
4. Map
The map plots data you have logged and contains some additional map layers.
Safecast (global)
µSv/h
US DOE / NNSA (.jp)
µSv/h
MBq / m²
USGS (.us / .ca)
µSv/h
Uranium ppm
EPA (.us)
Uranium mines
Other Minor Screens
Console
Tap on display to show/hide.
Shows internal program messages, which can aid in troubleshooting. (especially Pachube configuration)
ClickifyLab
Accessed through settings.
Allows you to customize the "click" sound. By default, it is not enabled. (novelty feature)
Mapping:
█ - Point View
By default, mapping shows your current position in a "minimap" with dose equivalent rates from a local database of your data and optionally Safecast, etc data.
"LUT" - Apply a false-color lookup table palette (LUT) to the data.
"Layer" - Choose from the different available mapping database layers. The default is Safecast's global database combined with NURE and Geoscience Australia data.
Resize Arrows - Toggles between full-screen and windowed display of the map.
Menu Icon - Shows or hides the top toolbar. Also activates HUD.
1.23 - Numeric View
Numeric view only applies to user collected data points, and the EPA uranium mines data. It has no effect on most layers.
In this mode, the details of each data point are shown.
Top Menu Bar
-1, SD*, HD, +1, +2 - Level of detail. This controls both the total number of points displayed at once, and their density. This can make small points easier to see.
Map Alpha | Point Alpha - Controls brightness of the map background and data points
Please note: rates are averaged together if they are in the same location.
1.33 µSv/h - The average dose equivalent rate.
(4251) - The number of database records comprising the data point.
2011-12-7 - The date of the most recent database record for the data point.
Mapping - Scale Control:
Changing the Map Scale
You can change or reset the map scale using swipe gestures.
These commands are also available at the bottom of the "LUT" menu directly.
Much like the dynamic range of a digital camera, this is always a tradeoff between contrast and range. The default settings are sort of analogous to metering for indoor lighting; anything beyond that will be a blown highlight.
Increasing or decreasing the max/min is accomplished by swiping up or down. Whether you swipe on the top or bottom half of the bar determines whether you affect the maximum or minimum.
While holding your finger down, you can move it up or down freely to change the scale value to a precise amount. Only when you lift your finger will the scale will be applied. This allows for much finer control than mere flicking.
Swiping left with a single finger will reset the scale to default values.
Swiping left with two fingers will toggle between natural logarithm or linear scaling. Using a natural logarithm allows for a greater range of values to be displayed while still maintaining contrast for lower ranges.
(NOTE: Safecast LUTs have fixed scales and cannot be changed.)
NOTE: The mapping module can be entirely deactivated as a failsafe if you experience any issues.
Settings -> Log File -> Disable Map
After changing this setting, you must force quit and restart the app (or restart your device). (you can also change the setting in Apple's main Settings.app on the home screen)
To force quit:
Press home.
Double-tap home so that the multitasking bar appears at the bottom of the screen.
Hold down on the Geiger Bot icon until a red "-" appears in the corner.
Tap the "-".
Notes about Disabling Mapping
When mapping is disabled, data will not be logged to the mapping database
To re-enable mapping, you must restart the app as described above
Histogram (Gamma Spectroscopy) Controls
Settings: Part 1
Settings: Main
Accessed by tapping on the "settings" button on the keypad. (icon looks like a machine gear)
GPS: Enable or disable location services. If GPS is off, the latitude and longitude will not be saved to the log file. Nor uploaded to Pachube.
Scintillation Counter: See reference information below. This is of little use to Geiger counters.
Settings: Geiger Counter
From this you can select your tube from a list, or enter custom options.
These are not mutually exclusive. You can choose your tube and set custom options.
The default GM tube is a Russian SBM-20.
Settings: Custom GM Tube
Conversion factor: Gamma sensitivity, in the format CPS/mR/h. You can type into this text field directly, or fill out the text field by choosing from the list of GM tubes.
Sensor noise: This is from the spec sheet of the GM tube or your own testing. Osamu Higuchi found a value of 13 CPM worked well for the SBM-20 tube. This matches my calibrated reference.
Settings: I/O Settings
WARNING:
Changing I/O settings may prevent proper detection of count sounds.
(For GM tubes) Unless a sensor noise offset is used, background levels will measure higher than the actual value.
Ultrafast Rates: Enable this if you are measuring rates > 3000 CPM with line input. It is not compatible with all Geiger counters.
See reference text for information on the others. I do not recommend changing them unless necessary.
Each sample is 45.35µs in duration.
Settings: Part 2
Settings: Display
Keep Display On: Prevents device from entering sleep mode after inactivity. Use caution if you enable this setting. It can deplete your battery if left unattended.
See reference text for others.
Settings: Sound
Optional sound playback.
Alarm Sound: Very annoying alarm sound at > 3.5 µSv/h or after no input for 2 minutes.
Clickify: Synthesized count sound. This is best for line input with a bypass to an external speaker.
Echo Filter: This allows safe use of Clickify with microphone input, but limits the max count rate to 600 CPM.
Settings: Log File
Recording interval: how often the log file is written to. Can be set to 0 to disable logging.
Default address for logs: Fills out the To: email address when you email the log. (by holding down the "settings" button) Not collected or used elsewhere.
Settings: Cosm (Pachube)
This controls uploading your measurements to Cosm (Pachube). Requires creation of Cosm (Pachube) account at their website. Basic use is free.
Optional Cosm (Pachube) triggers can update Twitter and Facebook feeds.
See reference text for more information.
Getting Started - Connecting your Geiger Counter
Microphone Input
Place your device's microphone as close to the Geiger counter's speaker as possible. It works best if both are in a fixed position. Using the audio graph screen can help find the best position.
To use the microphone input outdoors, you will want an external microphone connected to the headset jack. You should position the external microphone to avoid wind and noise. If possible, put it directly next to the speaker inside of the Geiger counter's case.
iPhone 4/S: The microphone is at the bottom of the unit, by the dock connector.
iPad: The microphone is at the top.
iPod Touch 4G: The microphone is on the back, by the camera.
iPhone 3G/S: The microphone is on the front of the unit, near the bottom
Optional Line Input
If it is possible, it is recommended to connect your Geiger counter to your device with a line input cable.
If your Geiger counter has a line output jack already, you can probably just purchase a cable online.
If you have electronics experience, you can mod your Geiger counter to add a line output.
Note: for connecting to iOS devices, it is necessary to "short" the mic and ground lines in the cable with a resistor. If this is not done, the device will not detect the input at a hardware level.
Above is a schematic by Osamu Higuchi. He notes:
Need a Geiger Counter?
There are many choices for Geiger counters. I have listed several units below with line output.
Personally tested:
- IMI Onyx*. Tested as accurate up to 350K CPM.
- bGeigie Nano*. (Safecast/IMI)
- GS-1100A* scintillation counter amp/PSU.
Devices I have not tested:
- IMI Inspector Alert*, RadAlert*, and CRM-100*.
- "Fukushima" (opengeiger) Geiger counter.
- GMC-080 Kit and line input cable.
- Images SI counters and line input cable.
- MightyOhm Geiger Counter Kit
Devices with known issues:
- PocketGeiger Type 4: Geiger Bot does not support devices that use power from line output. (Might work in v1.7.0 with audio passthrough if you create a 20khz tone in Audacity on a PC and play it back using the "Music" app on loop, but I cannot guarantee that.)
"The points of this schematic are:
- Divide the output voltage (in this case, about 9Vp-p) down to about 0.1V
- Do not decouple the output and iPhone mic input. Let the DC bias on iPhone mic input drop"
*: built-in device profile for easy setup
Further setup
Alternate GM Tube Setup
Misc
Troubleshooting:
An Introduction to Radiation
Radiation is energy in the form of particles and waves that is capable of creating change. This occurs through ionization, a process in which the bonds between atoms in molecules can be broken.
Radiation is invisible, and can be powerful and dangerous, in both good and bad ways.
When radiation is absorbed by your body, there is a chance it can break the bonds of DNA in one of your cells. When DNA repairs itself, sometimes errors are introduced. If enough errors of certain kinds accumulate, cancer can result.
Radiation is found everywhere in nature. No matter where you go, you cannot escape it. We ourselves are radioactive, due to natural potassium isotopes. Nearly every rock has some trace amount of uranium, thorium, and releases some amount of radon gas. And sources we make can be more radioactive.
A Geiger counter is a tool to help you measure the level of radioactivity; the rate at which it is being emitted. This is done by counting how many radioactive particles it detects over a period of time.
This is Geiger Bot's main purpose.
Caveats
Geiger Bot is normally quite accurate, but this cannot be guaranteed, especially when using the microphone which is subject to noise interference. Verify the proper operation of your equipment and the correct Geiger Bot settings before use. At background levels, with a microphone you should see 98%+ accuracy. Line input should see 99.9%+ accuracy if configured correctly.
Many Geiger counters have a maximum audio count rate of about 1200 CPM. Do not assume your unit's audio output count rate is the true count rate without evidence. It may not be.
For most Geiger counters, you will need to enter a sensor noise offset or the background level will be about 50% higher than its actual value which can cause problems when comparing data to calibrated scintillation counters.
I would also recommend an aluminum shield for stopping beta radiation, as applying gamma sensitivities to beta radiation shows a misleadingly high dose equivalent rate. (does not apply if you want to detect beta radiation)
Limits: Count Rate
Requirements