[[!meta title="EasyTimer"]]
# EasyTimer
This board provides two programmable timer-based pyro channels with tilt
limits. It is the same size and shape with the same connector layout as
our [EasyMini](../EasyMini) flight computer.
The IMU used is the same as on TeleMega and EasyMega, allowing acceleration
based launch detection, and gyro-based tilt limiting. This means it's
possible to configure a pyro event for some amount of time after launch,
or after motor burnout, etc, with the possibility of locking out each event
if the rocket is tilted too far away from vertical.
For projects that require staging or air starts, EasyTimer is a low-cost
alternative to use of our more expensive products, while retaining the safety
aspects of tilt-limiting.
EasyTimer firmware and associated configuration software is part of the
[AltOS](../AltOS) suite.
Photos of the first production unit (the current version 2 looks nearly
identical!):
EasyTimer v2 is available for sale now at
[Bdale's web store](http://shop.gag.com/flight-computers/easytimer.html)
and from Altus Metrum distributors.
## Features ##
### User View ###
* Two programmable flight state event and timer-based pyro channels with
tilt limits
* USB for configuration
* Designed for use with batteries from 3.7 to 12 volts
* 1.5 x 0.8 inch board
## Artifacts ##
There is a single manual for EasyTimer and most other Altus Metrum products,
which is available in [html](../AltOS/doc/altusmetrum.html) and
[pdf](../AltOS/doc/altusmetrum.pdf) formats.
This board was designed using lepton-eda and pcb-rnd.
The hardware design files are available from
[git.gag.com](http://git.gag.com) in the project
[hw/easytimer](http://git.gag.com/?p=hw/easytimer;a=summary).
For those who don't have ready access to the gEDA suite, here are pdf snapshots
of the files for current production PCB version 2 in more easily readable form:
* [schematic](v2/easytimer-sch.pdf)
* [pcb artwork](v2/easytimer-pcb.pdf)
* [bill of materials](v2/partslist.csv)
## Previous Versions ##
All versions of EasyTimer have the same user-visible features and
specifications, except that v1 did not contain on-board flash data storage
making post-flight analysis .. "challenging". Other than that, the
differences are primarily in the choice of processor and sensors, which
is driven by availability.
Here are the schematics, artwork, and bill of materials for version 1:
* [schematic](v1/easytimer-sch.pdf)
* [pcb artwork](v1/easytimer-pcb.pdf)
* [bill of materials](v1/partslist.csv)