MetaStock -> Tools -> Indicator Builder -> New
Copy and paste formula below.


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True Strength Index
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{ True Strength Index (TSI) v2.0

 ©Copyright 2003~2005 Jose Silva.
  The grant of this license is for personal use
   only - no resale or repackaging allowed.
  All code remains the property of Jose Silva.
  http://www.metastocktools.com }

{ User inputs }
pdsRoc:=Input("ROC periods",1,252,3);
pdsEma:=Input("EMA periods",1,252,5);
smooth:=Input("smoothing EMA periods",1,252,21);

{ TSI }
TSI:=100*
Mov(Mov(ROC(C,pdsRoc,%),pdsEma,E),smooth,E)/
Mov(Mov(Abs(ROC(C,pdsRoc,%)),pdsEma,E),smooth,E);
avg:=Cum(TSI)/Cum(IsDefined(TSI));

{ Auto over-Bought/Sold levels }
pk:=Ref(TSI,-1)=HHV(TSI,3) AND TSI>0;
pkVal:=ValueWhen(1,pk,Ref(TSI,-1));
Obought:=Cum(pkVal*pk)/Cum(pk);
tr:=Ref(TSI,-1)=LLV(TSI,3) AND TSI<0;
trVal:=ValueWhen(1,tr,Ref(TSI,-1));
Osold:=Cum(trVal*tr)/Cum(tr);

{ Plot in own window }
Obought;avg;Osold;TSI

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