July 2009: A Gumstix customer reported that they tested their Gumstix Overo products to the military standard MIL-STD-810F 514.5 (constant acceleration) military specification with successful results. The MIL-STD-810 test series, approved for use by all departments and agencies of the United States Department of Defence (DoD), emphasizes tailoring an equipment's environmental design and test limits to the conditions that it will experience throughout its service life.

 The tests performed by this customer simulated vibration for the equivalent of 1,642,500 Kilometers which is the average distance a bus travels in 5 years making this testing an accelerated simulation of a “Diesel Engine Road Vehicle” running over an assortment of road surfaces. Essentially, an hours simulation equates to a number of kilometres travelled.

Results:

1/ Gumstix Overo and Tobi expansion board combination passed the 5 year MIL-STD-810F 514.5 military vibration test.

This extended test result was completed successfully because the customer engineers secured the Gumstix Overo and Tobi boards together with the white spacers supplied by Gumstix and gluing the configuration together. This extra mechanical connection was deemed to have reduced board flexing.

2/ Gumstix Overo and expansion board combinations passed the 2-3 year MIL-STD-810F 514.5 mark without the addition of any additional spacers, gluing or screws.

Further commentary from the customer:

1/ The testing done by this customer is extremely harsh.

2/ The customer stated that "the design and robustness of the Gumstix Overo series without the spacers is extremely high and under normal circumstances are fit for purpose" and "that they "don’t believe that any units would have actually failed in the field".

3/ The customer tested 3 Gumstix Overo units: one announcement unit, one tracking unit and an Overo Earth/Summit combination. All three configurations complied to this MIL-STD-810F standard until approximately the 2 – 3 year mark. Under strobe light/vibration observations without spacers, the customer could see the U8 end of the Overo flexing at resonant frequencies.

The customer reported that this flexing does not happen when the spacers are fitted. The customer believes that this ‘flexing’ is causing small amounts of wear to the plug/sockets eventually leading to failure at the 2-3 year mark when cycled under this accelerated simulation.