Editing Dive computer (section)

== Additional functionality and features ==
[[File:Shearwater Perdix and Ratio iX3M GPS in compass mode P9070460.jpg|thumb|Shearwater Perdix and Ratio iX3M GPS dive computers in compass mode]]
[[File:Submersible pressure transducer for remote display P8160016.jpg|thumb|Submersible wireless pressure transmitter for remote dive computer display]]
[[File:MaskeC.jpg|thumb|Mask with head-up display at focal distance of about 2&nbsp;m]]
[[File:JJ Rebreather at Blue Rock Quarry PC290152.jpg|thumb|Head-up display mounted on rebreather moutpiece]]
Some dive computers provide additional functionality, generally a subset of those listed below:
* Breathing gas oxygen analyser<ref name="iX3M" />
* Electronic compass<ref name="iX3M" />
* Gas blending calculator<ref name="iX3M" />
* Global navigation satellite receiver (only works at the surface)<ref name="iX3M" />
* Light-meter<ref name="iX3M" />
* Lunar phase indicator (useful for estimating tidal conditions)<ref name="iX3M" />
* Magnetometer (for detecting ferrous metal)<ref name="iX3M" />
* Pitch and roll angle<ref name="iX3M" />
* Stopwatch<ref name="iX3M" />
* Time of day in a second time zone<ref name="iX3M" />
* Time to surface after another 5 minutes at current depth on current gas.<ref name="Knudsen" />
* Gauge mode (overrides decompression monitoring, and just records and displays depth and time and leaves the diver to control decompression by following tables).<ref name="iX3M" /> Selecting gauge mode may reset the tissue saturation records to default, which invalidates any further decompression calculations until the diver has fully desaturated.<ref name="Perdix manual" />
* <!--target for redirect [[Gas integrated dive computer]], [[Pressure transmitter]] -->{{visible anchor|Air integration}} (AI), also known as {{visible anchor|gas integration}}: – Some dive computers are designed to measure, display, and monitor pressure in one or more [[diving cylinder]]s. The computer is either connected to the first stage by a high pressure hose, or uses a wireless {{visible anchor|pressure transmitter}} on the regulator first stage to provide a wireless data signal indicating remaining cylinder pressure, The signals are encoded to eliminate the risk of one diver's computer picking up a signal from another diver's transducer, or interference from other sources.<ref name="Suunto transmitter" /> Some dive computers can receive a signal from more than one remote pressure transducer.<ref name="Perdix AI" /> The Ratio iX3M Tech and others can process and display pressures from up to 10 transmitters.<ref name="iX3M AI" />
* Workload modification of decompression algorithm based on gas consumption rate from integrated gas pressure monitor.<ref name="Azzopardi and Sayer 2010" />
* Heart rate monitor from remote transducer. This can also be used to modify the decompression algorithm to allow for an assumed workload.<ref name="Azzopardi and Sayer 2010" />
* Graphic display of calculated tissue compartment inert gas tensions during and after the dive.<ref name="Perdix manual" />
* Indication of computed decompression ceiling in addition to the more usual next stop depth. The effects on decompression risk of following the ceiling rather than remaining below the stop depth is not known, but stop depths are arbitrarily chosen for the calculation of decompression tables, and time spent at any depth below the indicated ceiling depth is processed by the same algorithm.<ref name="Perdix manual" />
* Display of supersaturation of limiting tissue as a percentage of M-value in the event of an immediate ascent.<ref name="Perdix manual" /> This is an indicator of decompression risk in the event of an emergency ascent.
* Display of current supersaturation of limiting tissue as a percentage of M-value during ascent.<ref name="Perdix manual" /> This is an indication of decompression stress and risk in real time.
* Multiple active gases for open circuit and closed circuit diluent.<ref name="Perdix manual" /> 
* Deactivation of gas options during dive in case of lost gas.<ref name="Perdix manual" /> This will trigger the computer to recalculate the estimated time to surface without the deactivated gases. 
* Definition of a new gas during the dive to allow calculations for decompression on gas supplied by another diver.<ref name="Perdix manual" />
* Battery charge status.<ref name="iX3M" /><ref name="Perdix manual" />
* Alternative decompression algorithms.<ref name="Perdix manual" /><ref name="HSE Manual" />
Features and accessories of some models:
* Piezo-electric buttons (no moving parts)<ref name="Perdix manual" /><ref name="tdc-3" />
* User input by directional tapping <ref name="tdc-3" />
* Rechargeable batteries.<ref name="iX3M" />
* Wireless charging.<ref name="Peregrine" />
* Optional battery types. For example the Shearwater Perdix and Petrel 2 can use 1.5V alkaline cells or 3.6V lithium cells provided they have the same physical format (AA).<ref name="Shearwater comparison" />
* User changeable batteries.<ref name="Shearwater comparison" />
* Battery redundancy.<ref name="tdc-3" />
* User selected display colours (useful for the colour-blind), and variable brightness.<ref name="Perdix manual" /><ref name="iX3M" />
* Screen inversion for ambidextrous use of units with plug-in cable connections for oxygen monitors.<ref name="Predator manual" /><ref name="Perdix manual" />
* Mask or mouthpiece mounted head-up display. (NERD)<ref name="NERD2 Manual" />
* Wireless downloading of dive log data.<ref name="Perdix manual" />
* Firmware upgrades over the Internet via Bluetooth or USB cable from smart phone or personal computer.<ref name="Perdix manual" /><ref name="iX3M" />
* Display prompts for changing settings.<ref name="Perdix manual" />
* Twin straps or bungee straps for improved security.<ref name="Perdix manual" />
* Strap extensions for wristwatch format computers to allow for fitting over the forearm on bulky diving suits.
* Aftermarket straps, for improved security.
* Screen protectors, in the form of a self-adhesive transparent plastic film or a rigid transparent plastic cover.<ref name="Perdix manual" />
* Software for downloading, display and analysis of logged data. Most downloadable dive computers have a proprietary application, and many can also interface with open source software such as [[Subsurface (software)|Subsurface]]. Some can down and upload via a smartphone to the cloud.<ref name="Peregrine" />

===Housed smartphones===
Smartphones in underwater housings running a decopression monitoring app may be able to take photos or video as well, provided the housing is suitable.<ref name="DivePhone" />

===Avelo mode===
An optional mode for assessing real time buoyancy status for a diver using the [[Avelo diving system]] buoyancy compensation is available on a small number of Shearwater  (Tern TX, Teric, Peregrine TX, or Perdix 2) and Scubapro (G2C) dive computers via firmware downloads.<ref name="Shearwater Avelo mode" >{{cite web|url=https://shearwater.com/pages/avelo-mode |title=Avelo Mode for Shearwater Air Integrated Dive Computers |website=shearwater.com |access-date=7 April 2025 }}</ref><ref name="Scubapro Avelo mode" >{{cite web |url=https://johnsonoutdoors.widen.net/s/dzj2qcpblg/sp_20941-j-o_g2c_avelo_manual_en |title=G2C Avelo Mode User Manual |website=johnsonoutdoors.widen.net |access-date=7 April 2025 |publisher=Scubapro }}</ref><ref name="Avelo mode" >{{cite web |url=https://diveavelo.com/aveloMode.html |title=Avelo Mode |website=diveavelo.com |access-date=7 April 2025 }}</ref> As of April 2025 this feature was available on Shearwater Teric wrist computers and Scubapro console computers. Real time cylinder pressure input is required, but may be via a high pressure hose (G2C) or a wireless pressure sensor (Teric). The software estimates the magnitude of positive or negative buoyancy based on the volume of ballast water added to the hydrocyinder during the dive after a neutral buoyancy state has been achieved and confirmed by the diver. Displayed information is intended to advise the diver on when to adjust the ballast so that lung volume will be sufficient for fine buoyancy control. Other user input allows wetsuit compression to be factored in.<ref name="Scubapro Avelo mode" />