mikey77 posted in the project gallery area in July 2012 as Tex has indicated above.
however that link to the inkless press website is broken.
Seems the inklesspress website may (?) have expired in 2016.
The "Wayback Machine" suggests they captures images from the inkless press at various times between 1999 and 2016
https://web-beta.archive.org/web/*/inklesspress
but my further searches found nothing about the rainbow voltmeter by mikey77.
Another good example of why folk who only post links here or in the Project Gallery should be encouraged to also post in the Finished Project area on the PICAXE forum to provide a more extensive repertoire of PICAXE related project that are far far less likely to "Disappear" over time.