DIY bio fans love their gel electrophoresis systems, which use a constant electrical field to manipulate molecules suspended in a gel or liquid.

Makezine_COTM_October-PowerSupplyOpen source DIY Bio company IO Rodeo created an Instructable for a gel electrophoresis power supply, which creates the electrical field that accomplishes the molecular movement.

IO Rodeo’s design is based on the MAX1771 DC-DC controller with output voltage set using a voltage divider–the user can set a variable output voltage depending on what sort of liquid is in the electrophoresis tank. The controller triggers a transistor with a pulse-frequency modulated signal in order to maintain a constant output voltage.

The creators have a code repository if you’d like to play around with the design files.

John Baichtal

John Baichtal

My interests include writing, electronics, RPGs, scifi, hackers & hackerspaces, 3D printing, building sets & toys. @johnbaichtal nerdage.net

  • Daniel Kim

    Back in my grad school days, I used to read the bionet.molbio.methds-reagnts newsgroup. A contributor posted instructions for making a Gel Box for less than 1 dollar. The key was to use graphite, carved out of a pencil, as the electrodes, instead of expensive platinum. I posted a followup later on in which I used plain engineering leads from our university bookstore.

    The original poster later showed how to use a Bridge Rectifier to create a quick an dangerous 110 V pulse power supply. I built a complete set of electrophoresis equipment using graphite electrodes, scavenged glass, yellow tip boxes, craft foam and binder clips. I even made a small DNA sequencing gel rig and a Western Blot rig using large graphite plates (large motor brushes, I think). I had myself a complete electrophoresis lab set all home made.

    WARNING! This can kill you so dead you won’t believe it. Be really really careful if you try doing this stuff.