from the fixation device 34 through connectors 55 58 so that the battery 144 and or electronics 125 may be replaced while the electronics housing 50 and fixation device 34 are illustrated as being connected after the fixation device 34 and electrode housing 43 have been deployed the electronics housing 50 may also be deployed through the catheter in a connected position with the fixation device before or after the fixation device 34 has been positioned and deployed a catheter accommodating a needle to attach the attachment device 52 and a deployment mechanism for the fixation device 34 would need to be accommodated in a catheter designed for the multiple tasks involved the electronics housing 50 has a round smooth shape that will minimize any trauma to the stomach the electronics housing 50 is also of a sufficient size that it will not be passed through pylorus 23 into the duodenum 24 it is further constructed of a material that resists corrosion in the highly acidic stomach environment such corrosion resistant materials may include for example an acid corrosion resistant material such as a suitable inert polymer for example materials from the polyolefin family like hdpe high density polyethylene lldpe linear low density polyethylene and uhmwpe ultra high molecular weight polyethylene fluoropolymer materials like ptfe u2122 poly tetrafluoroethylene fep u2122 fluorinated ethylene propylene and others polymethylpentene and polysulphons some elastomers such as thermoplastic polyurethanes and c flex type block copolymers that are stable in acidic environments additionally the electronics housing 50 may be constructed of an acid corrosion resistant metal such as platinum gold tantalum titanium or suitable alloys thereof referring to fig5 the electronics 125 and.