Best bet is to be a tripod: grip the phone with both hands and gently brace your elbows against the top of ribs.
最好的办法是自己当自己的“三脚架”：双手抓手机，用肘轻轻地撑在最上边的肋骨上。
2
A permanent magnet and a moving contact are fixed on a swing plate which can deflect, and the top end of the swing plate is hung on a coil brace through a spring.
永久磁铁和动触头固定在摆动板上，摆动板可偏转，顶端通过弹簧吊置在线圈支架上。
3
When using the idler wheel only, fix the brace on the axes of the two idler wheels in paratactic or in series and the top of brace has footplate axes.