From 9956bb06fb1a7c4dc4144c219af2726e1e99bdcb Mon Sep 17 00:00:00 2001
From: Peli de Halleux <pelikhan@users.noreply.github.com>
Date: Wed, 4 Sep 2019 21:42:08 -0700
Subject: [PATCH] adding wall follower

---
 docs/static/tutorials/wall-follower.png | Bin 0 -> 17761 bytes
 docs/tutorials.md                       |   5 +
 docs/tutorials/infrared-sensor.md       |   7 -
 docs/tutorials/ultrasonic-sensor.md     |  24 +++
 docs/tutorials/wall-follower.md         | 191 ++++++++++++++++++++++++
 targetconfig.json                       |   1 +
 6 files changed, 221 insertions(+), 7 deletions(-)
 create mode 100644 docs/static/tutorials/wall-follower.png
 create mode 100644 docs/tutorials/ultrasonic-sensor.md
 create mode 100644 docs/tutorials/wall-follower.md

diff --git a/docs/static/tutorials/wall-follower.png b/docs/static/tutorials/wall-follower.png
new file mode 100644
index 0000000000000000000000000000000000000000..1e864a0afe1346e0f793660489498ccc6bc94953
GIT binary patch
literal 17761
zcmd74c{tSH|36%*R6;4qPLX|2c9MjItYhqAER8i=_7IBfJ6W=XjBV_Dk!@^Q8nO#x
z8T;60@Our_d-;67pWh$%bzk@0H7=K&^?A;Dp2zd?d>n6|D$5aHqPleI)G1;G`G;z!
zPMwAVU%D601OIbPyzo2l?X-iM+=EjE-82ip4`<D#m84IdDh?yU8J`1wzGx>8b~ts4
zqzV6Zy45zv^wg<`+X@e*HC`GlCts|j(JWhqJi31#vf)NM?ryN<wl&7FsChktjlqxM
zf(rc^L|WRrGq*6;TdoA0y<i-A^Sr?Qn`94eUOU5dnm_#YWhNHWfGcF_7Yr(E4;Brx
zciKgrkOc*w>YmRpmesHBB=-w08PwHm7rLx|DmW+xP2Br9mM~O|5Em)CefCHNyq^+z
zs(_pM=FXy;!~BQ9fcGyEmP_~4(mb$wJ>5DjHn&fMyf1}W2fNnO=f6RSzC!3IoL_vG
zr+9IZ6)MrvmjPc1MTp*~R&&!pE_^fLlwe1%<iH5Nh1(gib`=vVK$1z=(H6<<HkH*@
zApUkYt<TWBkOgg%PBihFRID*=g-V2lmsjOR5^kRzqjAoZ3+(OMme^st*r;i?R2o`z
zxB;tSl1CcSS$K)(no5|*@C6^4by9l^p}Jnpo>rV#K6_+Bi8Q9R>WGP8Nlc~h+DNK#
zjB#D~P9k9ZDA3hXdL7=KamWOrjhk3{H0F~K4AR^<=u-2JwD4MIirs2#aK7XB71eN!
z#^VXUHu5U0>E6%{?8Az7qOP7WroFnG7u;|h(mi%&a;z)08`GxApaX^WYOvS5k`(Rc
zCspr~SlFi-Y*N-?<~LkozXr0z_iXGvNhQ>|w{|0Tljn@-mxB2#t(m^zaPm>~v@XeH
z9{D{S4LL9jOv(_<k}sv>vTGRDpnSJs=5CCjBy%jG=>pOOsPwvOiwv+!W;+l2``V2R
zxa8hW_N<O~JzQDGySKUtUb`5UzT6bXK1;!YmX#KwOC<r5l^GdEN3?=&03$Emt9pGq
z*-!)NicAfI^$*a4To}UkODwQ!8PE4bAQCQ4bCrsT1r0>eKJce^DkO;j%Yio>F3O2Y
zv7@8TfE`9M8Mzx^aAjTZf@%UyS8sh_F!Hl=(SqF;kG<;dgIS|=<IVvcaqcx=l;f9L
zIh(;#fP*7Mtq+>N)8;f{sRL1Sfe*c4F#G(pf$X4WuWEU{z?{9k2*C#7DS6b66$#vV
zHcl1^UMx(2<*gmIeAwG#jG*U$wo}+dz)k@z!;V{SpfKy`7>+T#0XENVFoPHTtz`-r
zpV^NZi8!n;zv{gTZelQ|$;<nI$3$|s&BDT>RNLcb=}3d;H`kwG&<O}Oi?V*N7~Yc5
z!R$LNcq5w4UhA%+S0N!5C^~T4PC>6UByJ&&X%{tk5AL<v)Kc@FS5#EAQ-)N+)TU<n
zo~-H%)0wsiv#Cb^kk~l!^rq{Oeddexdu7eM7rf3VGCc~Rf^>__(KviQO&Cw>GODT?
zeMV$H&98HBE|uOnGV<Xj%LHVPnGIj#;v>CyItuS2?1a)pz2^@CdDZBjBD2xzou4$<
ziQ^8nvz|0CN#ByvLPqk8`c5DeHSZ7OewrT4XN18CgVR}O1w3}w9w{zUY9R4rAOmJ~
z-l^JRj2W#Eb*Gr{O*-p$<3rqD$c+(+99YMuA{o<$141+`RkshZ#jNDT4L+KelX^x<
zBCGm|paou4B*`|y(-n^BVS~OBh|{d^ecXpDlB9|=aAR{fl7|m^VdIZ59ft8H$`a!=
zJFV*1vu@xvUQfiQ;&4VK*p#}VX-QI>s@d2_9s1N3gPLoKG?9DF2&y!!!GiA1J8h(B
zix~-A@m#%ok^|Pz#)ir@EPWtRU|+AT+($fK*#23@IhU5&v>n}Z4VB^BhU(z{BwLg4
z_agyK;~vz5H*PpN*nzxM!KAdJ(GoYAgqJEahWvC?7ZF>xSNO5?FBnGXn5uTh-Kn`M
z1+;2G#0_>cQw<;C<!RJm_7tP<sMQC*Dnb3w7mKaw43+f0&Qio|eFqtK(Os^`;c}XO
z_<>c2eUiP_2+H;4eLg5sMY3E^QayLX94q*0bBVYr;vKY6-YRMq>IZD@wYZkzR=N(l
z%aTj=ARdRYZ(>7!+CX)69+5z6YBd_q&EAk3qm;5@AFYnEA_bcT$;B$HDZk;Ky54mj
zu@>4kTASK+P&OeolC@+ZkwC>+VZ)6E^<At>C%aiQWGvX4yb~Z}k0+I~zR+H%fA6GZ
zyFF>$@=9*y9vW5>x;NA+dE;;vnP0O~Jr<ii6+n1oh19o|aMmaP3_UwqExb?MP?FdE
zIe^-BApbo&V4~MrV#s1TL_i`g@_nuQ;9W$t6J-v}e_mks&i16znX^A5%lx_LkPai#
z1FRHq6te#yF+aFqu3Vv}{)oW)5@y7xiP#+$oH23WSACXN(&o*`)=fPznELpYa{Z5O
z4&TQJerz+IBaU$*W_y4f^%=R$&j02$f~sRpxO()(bdz5V5^O<Ag<d{%uGvDepy~G=
zDm;t3FMWTU65DXNk9Nr?91NSkZauh9d~d#dJZPw3!l-Ely?jr*V(QU?sgiU;Ifb<>
zO-vcN;Mk*f(gII;X&H#V%qLc;d;p^JaCP`jHBASvxbG2{BlRgp6YoLZH)E^&gsYb-
zO86__0cq<)1*_}AR~&bRuLy1UgfE-GDtuRtKBpD5YV-In8xx3LegLtS4Y6JWL6W8P
zu;IP|i0S|hRiqZfE`8*OFs_1GXWCd@SmnY!RdD~7R-3aoE>#nG3No^h4?EozLA{cO
z&GK29qdH$~g<B7C->i?pO%4ZMzpH^1%nX8;pDF445Vm~JF~^Ua&{=A7QF`P931{G|
z{CCSQ#5Paw^|dOPhAc0CYaK40OOdcny8T%+XeWN_5p}@qizWtb+c;zDk*0vkj9E6g
z-LlLjDt0uLnk-m`;YyIdB(PK*57N<%TcICF*v)K2UcF|Vr#l)kCb?x^)1Ytmmc(A$
zxKMvWy-m^t>3HGnL-$Utq3h&Me1B_*<FWqKufaZq<g+$^DI;aG$bmuMAgXD2^<*r|
zQ$`+HN>u(@UsbR<OWwofSvTj}p%kl9G#~28po>kvYh!q9Mk(DN+i4=TUf;0McdW@o
zXLRVJ(?@!((?LE=%_(}NEF>AA;D_`C?p6B395T_1zx$IXhjbmBi9qyom&DEXS}(cj
zF+SrdDG9Ttbabt>sq608Xq>wPdNTw~UpA>BE&_QxEZmeQK$O&3#MLf1^|GUpflzw2
zZ%@I4;p~XvOJw{RKg-d@qnA2^Vr^swW#HwPFVvuqT4p`8b~iU9Yc5YligWDDGkZyX
z`#|F6N{8QE<qLWr;Wkdc=bHNomY>Pl3(Z}2!wQdnWYnt}Um=h-@f5OW2``Ir*c^UN
zltTCoqEKXl)aomx;eZl(xmIqoEU=@s{x%e<XJ@sZsWR#$3|r5OR;Q47I_5*)P`_vq
zwORVX9Zcf+)T0GfOz+msI<j4~TtsLZf)kB%O3^5lu);>!XF2^^n~U+}lhu3okoMT?
z3U?dkX9z~6Cy89XwValgF4Ye=uyxdTw76BB62<m<%$mB-Bw&6)bTIy|=~$JdzAc5r
zM(+lf#@8#(j&<V|8Fa^s4{5LF#Cs-oLQINa67u{=v}y$2t(|wdvfD^o8q^nhT<q9^
z0Uj`!mrP)%Md{{S>mqCLHPj=FOmpuf$r-~+KP}batN0U1pq5F}7RA0>m<wCbSi<-|
zth5$h(pVa*$jSYwzo)5+y!o-n4jr6+NrZLF7r#>4>jr|j#)!b9L<ChTSqA~!5nW8W
zE!#Nib}@1WBnviqcY|fXE<Hpy^*a5J;XHmOo<a5N_?}G07oYDo`<EU)gIH(l_eAEL
z!=}Fz4|o`f3f#I|>GzppB`t)2<zfc><ImZ{im-)kR)U||9Z^Oq{GVXtmdC4Gie}$s
zCTYjLho?|`JU1R?RvMf*hd2f@ss4BO%6wrp+|5uu8^VZZv<2QRN85bl_YPY(O5>2=
zja|lf>BqLwO2-2UH2^_{d~t6tq+nItczr(+_lX<I{@g}lNBc}nStKF;NSt3@j|Jd_
z{7fr?YVguy&rjM**}-3(-dJMt;4m2lfjX28KWS{u*B~dyhPyei81ZB8@%z3ufpG0L
zaz&Dd-)jIib`TkVKzwf=Ni)qRytqE8)6a=Pbo8`BAe!Ju|E$7i%uwpfLW<~+*6k|t
zW<tER{1DZ@Ap{ZfX35f6N{6R(0&9|PTtF#)S+qWvgP{J_^dqTm>OOKlFqyY<D|5Y<
zqs>!O(|2Z{GW{BhG}uca$QBRbP%qw2z6?1BdHkMSDanu=LK{e4!HmB6P?n7V-`{O^
zG#nRseFCR}d|*eIpI&<V#4CuVeKI8A1g2aK({+Lkg*xaa=FgR@E)ot(W~N<@aXM+=
z%~$opN}AFc<-5=H5_Lgm!OYKX-G>D=O1|umA&M)+vzkOIYf>-O93HR0U!W(}W9kM@
z%iz<QJ`_k3jCYECPcTD=J^6D;Fx;Tpg}^46s%>z5V_>{tIAuO_r=%RKCxi>7>xg!1
z#5=sFU_9VEULlS3bi2pEGO|M5$*!Iu*iAK{^o5kSc1e)9=b;Nmm>*$<uRBaf))&kY
zr#IF!zI-<;3Gzwnod0@S6|Ae;4|(i)d}e<y-ygV@_1)WsB%REeYp%Sc19oaba8Un<
z@K#It6?RWf{}^6LQ=kP6<RA&u>Y8|k{-chkC#Es>R4X@3WQ<8wN1ih0&U3sS#j1d5
za-%wN0QYXQ8(&tm>zFpR_P#<OEt5F*HTgdBrSfJ`Mn{sdd;f`J>S&>#s6>-^v!nN$
z@Uu<R2YunOmq$@>Kwqu6Yua3Gi(rz1WqhGMTW?2bEx@36;Rabtn9<VKfTIZ08%y}S
ziB-QK?rPgGcL`IB;C9oCXr(xz45&>DF_N^SNMfnX1Swsg$r561MN0iMG&XyH2)`3D
z!gVvX+Psw@O1AYO(l2bNN!&5kdb-*JU0(o)po#n(B(mQ`Q6sKLAzuU)+h|}O*3}>B
zSfL3HfGwC1xixCrm@}wcQsy0=`{+o2X`w14s9NH9H}dY?C;#O+hJ9_sTlDP&Y@X;}
z6UrwpVEJ0^>LF-<HO?>wxXhgV@Qx;2{KL>Y_FbN0*y&7j+qMu>y=#x2C2<;3d)Utg
zHvIA!n$ga$@r7B3`5;)H7#LeY?ogF=$17AI;+I{1Z{<gnv=0<14?8%~T4!w8iB}lb
z{KYKDvuKZ3{TH&DB+-$zl>2>=sDe2j+aGUO;O<U`YeoP34G;cx<Lame9gi5e#ID4Y
zrC&cj8z0~WjO<WZHWIu|@wi6=8Kg$@`>M@>k!K12ztU0iEAZ(80Dt3y@`srIcEal?
z9fiP6^<$6J+NomvTze7$Ky8i4kq3G0D*B0C@R<5D@sM;{_3|UKjzr~~Zxh_7@4WkZ
zZ>Su0(II2+!%qu4LLZ({={(lu3;5H2noW&xMu8kRsDX53-*%P0HF}T6ncaCwcR*vk
z0PrKfrrQ#<^J$7AR2*M!H(Hx6JWDssvxtWbg;We@lKNvWK3gY2+|LKY-o^0p{sMD_
z0bftmM|3i`{&s5EAB!EI`rqeZE_!QpQk`g;+p_wQ`{{YagM`t2&dhd|KX^#{ZR~QK
z*>T8wewDewAdR#A+8N6Y^*;+++N%4}Fp>cuv+8lMZsk5JPUR*WWc=9mR~vu17@ZA&
zT_z3&Yp*}c`d^)N?w=)QhdzxpjQp7d^zyz+@0PHEiF5*)xokfw`_HCIhjVxED69kh
za-DVg_IsiL2lHuP@N?w7zs&S6m-~DFr@^`Vc@)Ci!eYv1h$<#4Hq?NN=dW7Q5dGit
zeA*n`$o6*|{PxBokmS}LF3Z{dbSWWF^z&m&Yo|v4HsI%k4)(D&CVXU>@-MXU&yX=j
z_v{O%b|7Z_=WbDL<5J_80phxkLK7_vA{E4eb$j;;xHuP4lYiSR=kL(x_!<gttN~G^
z?zfQEN+O$<kX-1`k7ZxBUJu<1E4;(~^Ka|--($Uh4fB7B>P~RSZ!7*ghQs^SKmH>D
z&P@<gcIB`A|Nqqq|9|dEuJLkwcEVW0rnlJu3QctH)i0l=8Vl>#Fk}a3yx?60msnaC
zDN&LyAV|F}|Fx8*CWvjrXW;&exA`1wM_)$_ogax6G`6`br9tyA$I2kP_)0w27XXWi
z%FU8I@~;6>K)E^8GdPibJSG+K+jIU`Q2Ey>LFE?&80yJmd9;wu!&{thb&7ZpZ6@+e
zmR{N_|8!%-{}-tE*Wu*og&*`?&IK@K%VgcmAW<~4>jMU*zn$^zmnQ^_2_yu1E=y9A
zbGu*mr|8$xy}#OENAn*<o_&kc1}oOv1)HAB{2%>?+ZQU6*t!viDjwEr5C?SMKMyD|
zVnb2Q0|WFT5T|&y70St~{u5>~{Ffhn1RT_3_9++U|Bs96zGlOD?Y{rXnW*qy`tny$
z@cW<_!~X`m{xa@w<YNLM{`68+7@(Q{)6ZqYFuPUE`Fe(%bEqISrQ-_>9rfFQ=Y<`>
zS=0#+6%y%@{r?Ixma8v$y_Ml_&;}DYPUO7^z8}i8XH5IA-Eyf)_PIa)p4dc<++><7
zpDF@;MVY_s7|rP4Hp}N30?jodIl4nAJCvw;{ie&8u1Y>9rP0!Rl_^(7Q0w2n%IbN^
zwpI5`CJhmQREOVotSt4E1Ncck<*C&pa$KA?@>E}m(99$Lf{V9{m0}Bt>nk^!4Dryc
z13b8CMrr`CJIYn_Ps;IV$f7lRxj_T|vGU`yxpFRoM0)lxykB{N6Ui<nEKD!GcC<5p
zdkBcLL-<8s$MWOiz{vcw;~K}Ut+;RT4-(h;NxTAphH%Mhv(-rW>qjS!gh5Jb(QcbT
zE85wp&~wLZ#GeUIJTS4NWk^I`OI%@kYRs|RR;av746tK(7Lp2J$4&~A^hhR2+{_%Z
zoTHDw)+5!Vhl$huL7=O;cz?p(mak#evwUxgTgr6A=WceYmm9#%;dzmV5YG|oief?;
zI^1ry6rWt`hOWaXy^3nIj@>|eYl0`~XsX0G#`N>6(|7_506b(dTk(7*Lw?e#(Tn_U
zoAZx|RxSff(Obm6tv5DFWT~iWh~NS6yY-QYLuBpIA@)x_!DqPL^(E;KtdF<i1<aK*
zW()8X)0AmQ<x~Lm5P=L(iTC+H&ZFREI-sAQk%B)v1uzG$uyocRBFm-yR9t1|0Ffd8
z9(GkdTUn5h-h<b@h&4z}9J^E!Mk(^bG{b)b?|QpTLv|<qNS_=X9(0{1r1?xI9+W;q
z>b3jgyC!H$IHAoSm^D*`V91XW^Q5V!z$7A`+HbfOmj?Cg%yMo!E416`b6rV;7C!9{
z0C3ia(2<eJ*gtXU#3B3m$~iFfHJ-XnwU_?)wa$~$jj}3ae3yaz6JG@@OQ!WEo>p}*
zNwK8ld-gEnVTe}f|AMsgdWTP|(tG39KUnn$PhWO`q;jbH)o?xYj`rKQt0NZV{N%@>
zA}3VTn8|D<B#D=7#ApP5r!xc<7}Reu_F3~xIq0$~X}x(-m2I16?ia72iP)@0o8?#6
za|t#wFX0b^C^@#4;VJ;w#mL3Bxt@P|3GxE?m5_=FuaWm28|~xi<xh>Fq%~zG&F<fS
zA0Us%oTP1i`K^*e6c-)P%<_?`h-yI@oq-$6#)G&2i@z=G)rpA9;TmqTIk;a_;A{9Z
zyt9W5UG*jVMvH!*<AHwK<!FEYsx7d56wqMVEn8LH(!jA{V`iP-QPIuXIGmdgoJr*Z
z9<hyyszx8THkKwa{@a;O>qzISkOv<)MpTmU0k8{=e3LF~-Am^TJs;zg;HBV;&rL8J
zR?5PG_%Rz^;1$gba67A+QObRE&P3<_D)a9wgC#~C3=%`!D4Q)8vq6)UZx`j!Yar7&
z8<?7f0M1_6q3WSsZHq5Ib9WFP3hIxgrJwg(q52wB%4$<Tiz?774b)!-n6{G&F=dY|
zuaXP0mYCDh)|BTI<pIa%)h93FBK$R=UpM*Cnhn~Scunv=DK<Ad<+*8rYRsRy5?^vu
zAM3d<m%(mw$zBpu9=I`+r<(u2pgE_l^aR-Hvxs(bBP$W&iV1r$T@s5s&(q)q27jSc
zs$YSy2C|tjK!na?P1<41X)vK*MM{F^@g&pGyBzJpdeou~$SU(Rc1(D(g%0v!<Q{>H
zFom9-^zMFNH*F5%wcl68-!WmK&E)I%P;pT%)#4Pl#oQ%l1)rh}pl;T=J|ycsm<nQB
zQ6LjYQ&3HILSk%8$(Vs#xlr|q(J&`_u_8~+z$SX4=W;E?=-D^-a;$ppGgg9*Q1K1<
z{yb3O0F6T@-_&6*<5jHQO9O6tilM_=Ob>eaC|X_lVuPy1^=tn##Jsyfs>f&C>`%x0
z`cYQ=^>=(DFDhr{XzXAAuy3VR_d6((LVTDVo(tkuxfGza^zAarb%6EGf4^izkM4(U
ze7&Y}+5epVo?d(JbNKn)EfbK4(8OpCd5Abc6sg7+9vW9XU&b}xVlsM8Xu4%U(7u0o
z((Qp&QY+{hg*^ZaFr;oygf3(}#QChy`+>H=INPrUb>;X1ffdz#x9xyY`4&NArt<cU
zvM&@s43-yRJBgNJ@}DAAHnp_S1QY1S9=^GA^gjf({cS?9OuNRAC~c}77~k!xW&_e?
z4rsJYM_CUuBUCqq#D9h!;&_1zvddEf)4f=mOSN~dB`<%iV99}*qxkMqu){85*#9+*
zr+PQN2-d+}15*{Fa+N)~k^)?wf)#gQJ)&5cjZwnG9#Ne;;Y(mN4;_XSaNw%oIr?om
zUVEvlDwkrM9BE_s5Tfi5tR5M>9I_Daba?DL(KrG_Y*yyrC-_H@-@LWvpPHM5e6ITD
z#6_?mcuVHR?LfXt^EZ!v)p_P?01cT6uM`_=2JGG9wVA@aABA~__shU8_OBZs_I3B0
zl;gMjh<<(tI!gUI%AQ7Sxm10yPMXOyg!I-Z=BvSh@s~Q)yFnL^2TDOPui3W_HB67(
ztV7eiA?dXn$(((CP5GPsqVGv4-b~n1lu@_D`84;;C=DW%*!;A_fkncov%(im-Z(?A
zDiY7=E5}hkx6rrg*R^cI7hBuI$XqBH>NG9Y>`IsmIK@eKaMx$3J&D=pU!1i0J=m<@
zO*&1KFyoQl2@~(;GhPn;RCr6)+ValQ)!UEm@(<=bKKWJRX=Ax8?SLFEZeuh#-FN)e
zstN`PrAsWq21OO6d8jp1L1Mst{}7_ToF-wVw-B+_dbfVkbs^>s`{MJ!<LfDp9`Hjg
zPcIx)RR&cHKKR$w1cd%Nw=GC(<c;N8KWPr+U;SUWV^D@*`aE5EP_@$u*7*wm2oNo(
z@k#(35tnm88%Hg?a)d*WZ`0j|*cXu`@)4p8DxW6tk(_#Q4-wfE0MpcqO(xPm2D!{;
z!)@x?Y6A1qZ4Uk~nBJzVEiaIkTySOiL$BL^3;sipmlx=qH3mdg@1xHTJCWna0!_V?
z!9B#1WxOkqAJMC4AZeV@?fE?q5&^KBPpc+jMebDB__)-n;jRq3R5pz7CC}d08Hhs4
zmE+53>-KO{3lDMOk^_WYV_@sj@HE%2&{?p6JbGWFcu0lfE&577DzK!KDjzWMvR_a&
zopfOv>)#@5d9C}gxN&UJItjGY@f)4<4WOlq!-pM!4`kXffz%m=@O6wYSB+9czlB#h
zS++$^puMeYo2aO$xacbpw}xBrF~xtNeI)Lw>PhxHXFU`O<iDT%&VR?8AFRhW?ty`F
zfQ4i*!RF6e*)cN%p;vJ9`aCfcxC$xWYi5p;JwueiKdj-OX9G8up>DHXq}BNj5m|@l
z4_)I$HowWptVvZU{aCdXxGN<EG?io=&ICv(?naeqcopX3K0irh<AHKFaKgLQycJCK
zx3MFayLw0`aKosxCIWXGP+!}1_#1xMdKwwHl{JYovqC{$VAJHR!^HOLORKgtfc^lV
z$^H{v0G+^56fDqo+(*K`*Ra;QTP%Oo&<T^08fFA;+q57Ge|3D(nd71iO7Flbm%}5=
zIDm1Sw?zM4S^$u#uDH?2!=G&w$FhYgQ?6wC%)L%PV&Zau<Mal%&c<mXEzvy6$iK@S
zeo+@es5!Y|oG^GUf<E)@+)K%Mu!^U(eZdw`g+b|{$~0N-0NhvKK$B?bv=JO5cz>sk
zz2d^mvFZaa!k9IO5F4bF2oLUKA_V1iyx+qxpQIiq?g#~;K>0Wzzy*@selq|E253(v
zha1yvNDB6{Sd_dpkm@%I5L|#J!(M=5?w9-nIP2>NSr%T&8f^c2svD4NFtx8XpUdmq
z1&KC7)8@GKV|0P`!r5YHH31n(`Q45%gxj~eCicBUvs@`QV1<}s1@BjkkB3vYSK_HV
zaQ(gANI|L1o2kiVoGvM;b)B`iVSWq(2QhOyb*OB8AIMT3i*6J)niK$;hGTr(8T<a~
zxYtpFZPU9^k%DhJNPWxUk~@v#C>YV1Zl3r_k@eBJt84MPS}{0}2}6Yq;lsZ0$H?o0
z8cU<)knlTF`&;#_Ey`%#>1>zyIjTu-&gpV4KeN3L-IdkRpP8XS1M4ho(8qThMpg_s
zpv;tWXE(Mzy)h3KcNJyKz=Lo3O~)3W=oBU9D_)Fj(+R3IrS&KAV{N~0o0Qk#EDNE%
z4+%NS=JZriI0cF$8&E}N-09RHONXOW!GsSXUDg@b<!B-KOfrz=M-W;77~Nn;Z_EDw
z^9SWtfqn|7@1XJPZ0K6)I(rdTs4BRooeBLHf1BA=XaTNpJBZ<ew(obyAXU!UMG3u2
zt;%5@H?&DjPlKcG&|A#yD>6f$XqHs+xtano@X$w?r3-up6b(bGdGmA|n5I|`fX1JK
z=TyBT;g6D^e2z9Rbl!OO`D;S*<Wa5zMcG%Zu9;U)ZK)Qrz_M<*?C?LhU#@->=rs(j
z;my+nzK)pRyZ@wr0$0@P?E3A~R^WbdE3%R@SO@NT-KWcTv}46MoV~swx)$^Ic%+tL
z$q!HYNJ71$Zp^TtMUnIY(kY%<B|DWCTY)j&-W{D`h{RBEg&LNXzai5ExvUN3A3{{#
z&YlKWZw(P*ZyDRvoh94r(s`c>Lu-3GcTyQ*<7zR+vlA2i7>9N$jje;S=m^8aYwwn|
z{z)Jkf-^UgN*pzJV+?eVPWe)9zU$w~>9r0IxC9!6!G8F$rehS{1?9!Q1Kz~}<Putw
zxv*bzpOTdb@&aALkT4PLpVwHp+4CeS$|)HghM?mAw2!w~mnm`SAu@8dug*CaxMb`f
zsc)dq;VI~9PI(lew8~{Sq;M1uGg@>Ia30!PvpW>gF@|Jdg8T+$cpFuz%mE-|D)UuK
zWxs)4xMfe9?&x)8v$Ex4iNYCpf%}0yykG-Mgh24*!paUs+u701IVWPGTj0}ud(y~V
zMgr3i#;Z0-cL(YYg~6b`gL9DCI1QwZcd}`Wlh^<~2l^cJ9eCTOXSP1=Npx4fqMxHz
zxFA)3W&*8Q;wu>10PtVZniGbKlzYrEg5UN#xS>yX_W#K~<v4n20lCMN`ZhzPQ=wEG
zEN}l%2hqk80*nb~s=u=jRRHsN%{6qwzpp0k*|zgK^di<kt^z17{z5MOcAKaGW@(!O
z94a42h)s+PFFQ;Z`8pf-nhg^huyxKrcYUW|7GT2qtxN7>l4{gelwT?=+9F4e3gskK
z`v&M2Tao08AtNof0D+z#&U1M6U4<mSfR@LV!|>ae>Khww7}585pc}fHrVZ{^T&6SI
zAAgxw^>di|Nh;d*o)B?$&t-ZHEa9*PJGNZ`M5E35GOY_Mfhm_=?UqcPsVRDKoF;|~
zye`D_ko_@_>?-)gt8gzN(o3-t&r_1CidwhzymGF6{tj02I2ep<Vo(Gfeurrnr!#}A
zp9!AKrczwTe~)9r+)({S<N&>C>ufK3r@`KY!SYVb>=7>y&zmD>k)>kut{)Tz&+1F2
zcRE`oxA|C((7{K~LUCL6sJ{Baq>+FS?r0wuDWh)jqh}?nhlKGVLgVpWq*n0uJ1Fx8
z;YK}yNoRpv6K1U2mr}^8V1At0?tUS&3NJUCJknvVTd5fi=@@#!3WhAJd+X8lO_n)0
zkr9HFud@Nd#D;X!I*Z<0<;r@Fj*dmM4}D;s!?y2X^prwB-mhV$iu#}}%3{l=+ds_d
zG0i+)e4zTnt-_>(orwvL?UGao=FN28(YBL==33XOiJR$#V<05iA&}N)(<1WXNZmRW
z1fS1;X6iW+j#c9`U!f_dd8`G-4$#L1-hH{Om;Cih%r)7^NCk8uD_G_I-H7~a6dA4W
z%sSql0b@%I<6zh^{x++Uu6wYVzM=^)Yyyw>UI)y=^M^x^L|3TTN}HrDmDhU5?XI?U
z_3An=L$Km*Sd3uKPuZzhe`{7~>i+ab_{T-OlF}($&_E8k-O;|E&QV~N6&qtv=ayjW
zF-;A#D}k@pV-tHkR~(iwkg17=V!x`LDVCbW&-j^~WO(;+Eh&9A@a=plZc@vQ$gM`r
zL%6cKw^M`@a+^BFX;pF%&W}0Qc!&ViHwFoDxv$n$`~bv+Lv!m>ieH3YO@)P!qQA%?
z)qv)H1-{QLS-^_NW^ira?-E?4aKn9<MKUO2v*2`ga}uzxtcDX7w;hI1Nl6ZpdkPLe
zkh)1kl3Q#Joi}vjS6ki>lo-jsj<ThyKRQ?qoF35Ii?trq?ZLh5SL#}=7)I!k%@8X8
zc%fKgTV#bcqOAy<mBTKX-*Ku<1|uU6|KOI=(qLHDVpxYvVy$T%E_sJY;&71(8eV>&
z1C|op6U5A>&2?P7>~TB%?u__mf2uRT(TH`|N|IIMitP`RFo{M3d#xfV5clraYINeX
zFDVJP&?QMd$@*?lE6T}EjJtVcSt(utGI;Z6``W^*<212Vu&13hBVw|={jpe^4*alE
zJhNR9Ny{<8v$>m>1nVz1<bYlXx<(;vQPNdSw5m9g_+jEGld`&1%WS^;%S54dzx9DF
z0p*L?R{+B}vb4eEu~RbviSy&Jtu)>>?u}_RKT}WZQMq(u=0ZI=?nnjdu+-3X59MuB
zbXpfF>eIIBzWY`K-rWRT9oB%FcAC4AQs`sBTR<f<c<q_)+X5*$j*k71m^`AwleI3B
z_@X_q4iW<EMj|I*LPy4rLOt6(eqKv8YIgekF{yxjvcU!#K(l`lV=-~W8x@dhb?5Ry
za)R*8OM#CQJ6+)!zRL_>TgvSlTb`b;sHH48kgPe}M|GzSTBo|Vjq4_2dxnSK(R)<7
z+JB`q`?(g?*<Z128*sol@3dM58Fa2V`(mP-kMl)euK8;qd*}TYLi{bi;%~HczJjF_
zm_i?atY^5OPrt5%Kwv+ntw6&e17rm~2j`|%{t&}YY|j|7)9X-Kz`Bzh)zw^>*dF%Y
z{En1IIk?0uBtc+`TYx=$_nW?-ft5+BK`0>4#Z3|}Z3x@F=-V=h3zpo<?Vh{r)-6La
z(fQ=2b9#c{;XMp;gG9ikPvS!<s8Gjp+{+<?QfPj1ji43vrr4#RldEF1Ph8UY(Mqc!
zO|Geuy;5_xHHQ)%JizMPD^|UXx6=`-Vezdk;>eKsFv=xf`G_sKRKp<4!Y61gkV$I@
z1kDs`q3<(~spKB($UEGK6wK#%HHi5BHrRNF6s-#CkvP%|n|m82*sSS&^SsE+T!WFn
zlNJN~>2t$T?)exS%R6D!yy4@zsM)|CK6N=ms>g0CUu(MHp>bV#(>DCq0&vK8_1n7o
z5=%bPJuw_R{a>o{E5;M`=biyVO-S6)+BE$t*=o3qq;X2aTpMrUV7AormNC~NSBG}a
zl4tGjC!1z^%)XS$b!HMO3-XM*z$jl#qV%y<%Ap3{9cdr8<j~rQopA0banq3VUj@kw
z)9aQw<5u<_q#9n@+^if#D{i`G7L+JIHh`lH@_6)Y#d2Z#Pu^n#emu|1cYCwgk1lM`
z@+GvkF%uu_5qH3zHXAmHONg=M<W;9%rhRNb-qF-q;=P~X>fYREw1+k>bZ_g01}fK6
zwB6OYCokq)hv^n8>97}kysIZ>Wt~!MNh)wOi<L3vNx{GtF3i+Aj(>fnV75d{cn(fS
ziNYbSff8Exmn{MgSG$Y11ri2H5ABeyR>|Z5!R><(rDaDu+7*6}115tG5>Yk2a65X^
zT+*6O*c)rtW-`^;>Nk#AeK1vbZ$VPPYwfDp9$LK%EzlC*T+(_DoyrTu;G^PR(*<Vp
zgJQBTVJ1s%ar(~2aW$XAo~L)*(=$)*rXdKxIXYl|5@aXrMXi!bX|EAa=FbuVM_~nu
zQlT^+2iGB<cyH*GJX_EcaGlvh`A_P84kr*Tq^UB;F1tq)du<0d{Sf5<7$<@lCsE*e
z!X#i-*EY9r;epz!2hTArywVI~EVhf}K~#|~SK7WBv%C&7q!s#Bdw}e_Kh)o;PO!rt
zY$ic#gTd9wC4H!IB>A96v*}T_;R5J+okd#R(D@VwCbas8{>1mRInX9TeCl*{tR7zS
zZqH0c-PYf)OOv{1y3QqQ0{g9-q@Gfb&I%KnAhO+JGjXb%v|iz1#{{H8V(33dxL@wR
zvdYNziq4)DZtHBI$+y+3*ts-kL#i@Fyf^*m!*vj+dzZNPPGM(lTtNIR(Z_h#sK7uO
z#-1^UXv%8yIZX;r8k2rY(~xVysYkducg}2<`+@Iw?MsaI=hp~KhvPfC-kBGWs`%bg
zd4r8%*$>#O$F)^W!K--2%>!`d>&uL%eul*!jjej7=9i>D1q(d|X9L*_l9jUk$UxXC
z)jfD%=I5z$^8?$FM3(bQHXq+rv(D#^Qw6P*Q5=zxh@`oQnm10`v7YTPy!k?}aw+So
z_k8W4=n%aLLT?Wk7CNP2GmB?SJ5+HSW)+BYi|U>VX`rD-oiXs3+_c*@`?9HOwoT;M
z2ywVWLL%wmMY&l{&o2|IH&W74NS86Y+6(0=?+$tZ8M_Y*3Rv38!9_(nxYt_lMG2;J
z&Ws@NWwGUJX5SG)jmGEnRQVtS{;1p}?*Zm!iWRKV%V+irxVNb9=7i2Ewb;RK`WzZc
z`BaXhKq(w!&1kbw!(JC%2l8TNVZ`m0RP#`3qgbwZD^#srT*A7ex4`mxUSqN2%p20H
zZMdzpoe;id%dj0jneAoVHm`-)q2%qrgAG<-aOwBpEs!U@ib;LEKR;Zx@>|RL1V=40
z5LZUObFZs^h=KXS?Dv>KgqFYdBqH6V(_9jhK$kxJe9WoFRKm1@t5cEmu=feI=i3Cw
zqg9zbu4JJvPpG_t5;o?WeZJa)#XcT<OPDI_cAlWUH=HB)!zhr}*(k2YE;(G>B(KG3
z%y6Vd+--|winj~1Lj%#Ouj1__jH6Bmg(&XWkza_dtD4cotj!)h3-HRq5X{bSRhV{2
zip}0N=^J>2bluwY0K~9WdU^Nn_OQ26tun?zf6OpK^~^oLMzj{eMft+DSsT5_$1jW6
zT*C|p?<9t@-S!<{9I~@|xkM|qOhu6*zTpcnD@Lo{EBkw{hOIBRDC*bF&GFpPuXOu4
zG5m5GINxg@e4~<V3$?8bh$ZjesO9GuXB5R&i8a#Le@AR)7Z77w3Tc+TDn-aa+e&^b
z#%LI;22vygt}J&~C8jK?)^u!V-v<V>%ipRSv7KNmE3~0b2~QGUViMTiCLmzsz8Lr@
zrDm?}>CdPYsUPBYE6!%~E>wdOgdVNyCQ+qv%cn1-)X>qqH*+66U3mw$pzCdwa)6mK
zJDeeWpwL6(66NZNx+YzC#3_K<Pp;wqL9l!OCjvJLTq-R+FO!cC#@su=5B7>{B5eTp
zClECk-$VG~XJ(lIWewf_kF>ypX|B#SDH}*iwJQ(c1C6KJTM6C0C2?Dm-*^h^BKmqv
z+`5nUQjglXZ3FULLTZ-v>xioo29#4Ts|bhIZ;$wtdSCUbd{>R4Hf!Tc0w9kr*7$|&
zH_Swv{Z5@gPYvsq{!S*qt^aKlf|=Ka7EZmkR+(|~p|6`Pa6Y<<BW6+_q=o-5vl2PA
zbMA*@zmmXu@~TIx)yz%!XU|XeN<v+?acjF~;kS4DhN&fdFaWYFk!5f#fOP?x3-R4e
zrWmIifcH%6v7LI6f97Pm(OWbA(9Qz)&1bXcBuftWr``&)*RobV=@C36Vvz1kx|#fx
zfjIv2D~^#DMr+dcVpRl&*GDZ$uU)gl>Tp+mO5G_nAj^R{Jc1;LTBNW;g<KI-M@N>s
ztR+C67k;KBjWGD)c{_#ii$1m9b<H=XE_0^3j8Z51g4;w+XP=f5I~w1qZ;e&iL$y!`
z%J4N1y};>*Pxts9@%fyo;F?{#9mWSldpYp#AYgqq_qg;5G#L`J5yML3@biOX9xNPu
zhP+?6SSC0p2?Y(Y!-D`MH}0w15mc!a7lIMSI01Tze@r(hT(Ht+GFi!e$TIwT*|~oA
ztU4{R&{W*!6@h*K1%0P9csKAg?jJp=!q0nCZNJ%@DyS)Wrg#bUB>LvQozK*j&ctpB
z7b@k0=_*un=!(-fI6URI&RbsXHH_uSd!xhkFz<Lu0rMhsRAYPf{C)=B@LgvLbhG#x
zOeAac)zV#Gz`IKhH(~|z3xUTkJ>mzQ{XkBwjU8RNpR^J#_|o#rbBA8?!Fcce?34z(
zcLX3Snl1D+KDy-_99xeY6`4!#=v=AWHg$MA{n^j^#&}zh`?3a7w!%=69c=O`u{oq&
zXd2K>-E(~cHEGvHUfBwy_p*@OpTBJnW=TLQRv*q|bSw4x&#XV4N-KD3F4-80Qh?}x
zU60F#Wo-GkGF0oU^&vzR4vcjQ%_Q2)&AIOlUast-+0M)8%9d<CVz&pPH=;l??uC(w
zcQjHlTr4VP1-Q1+^|-*!)gIxIr8TadujeNYyF*c>CEY{~B6hRdFc?Pi@TWYG<es|o
zJISrPaPc-5uyxX<?;{yV@qqVuu`P?}EmZlimsk_CW1Li54FNn=pF8Ev*(6$Rt=88j
zYI$JXIC|G`$NudEfl95>d1BA6qi#Dz_rpmOKV-Bf%$f0+RPgvwavX}$c-OmsH8Jj?
z96gx4i5dEuV209d4+uFKiv^H2k2yF=n;+9uSs$NO%rHYYUw*^*y!sZt5$@E-2e5C)
z>lbrh2TAJ#3l={NqAA&yXo+kSwZ=MyfGfl-TVWWyW^G#ind|*n8;R{N_44t$sWG=&
zU>&i7;h&`TaW}X@hE}%N5TOa9K^Dfuxeb?bATZ*1j4U?^-{F-X-p+%g+F$sp{#HO*
zvfcpR9WphL0g;@~!-L+r3cIR(qgk0&(~>J)n3KSgoDq6~YRX+XGXYjoY8WG^asy1D
zaP;SGU}4H{S!8Kx6wJr=q!F{`AgZkxC){_kE{7@hBgLJ*0mI%V21yoE;Av#p!6%q2
z96=?&2RtTw-y2O+fAUT+);UUWE%$gDgPig~R1Y!H)!o1%kh4K21zPA?(6D6?q-**%
zlwk@Wsw%a3JF;KUoG7JakK^@Y11bd%d?RE|%#MadA%PWjrd4rm8_vde=>g%wSB!jC
zwo7v#(4kpL;kg7)FQPc84g;lvs-H!Q8a~>0ZBN7+HLV5qRF)|sC6D{$fL=T*h8q;M
z#6woM^;U=w4}XkS-{rKH0sFy#*kht`Hu3xb(ZeSHu+JH;kK3u3avQ`0rC~+ZGfuv}
zzd9%OH~>`s=G<{FLksQFp1dtd?-=hkM5@UnM4=~E)AF%MiG(YwdCP`@v6GQyDp*Z0
zM!s!$5RhlTR|RL^#`~raM71zG2Q;-%)qWQc09@z0e9J!*R)Rd42>BZnINSJ&r5=3S
zvVk3%f*|qReV=B>$oJWX?dREy>uT`rUlwM+(pAFEauWj(=BfC7k-K#9kwUS~n(iKq
z@M-id?y;x`kCBomlhZku4$KNzitp0@Fvxi@&nFi~d(}#RtZJu2j}!%6E%(xCNdU=A
zO#`8p3B45mVua0z+)h|Q1-51$_!nz_OyJ;+o_DUWcgwA6zj!2rBm-N6aJbr~jwf@%
zq6EifxIsjrrw7qlVb%vj%ge<k^m2nE2l|uoVW>;sX(v-_U~Y7H!Uhn8z@$L4MTQ+7
zE9>{COvf&}uK`pLpT|4DWOpm~MrZ8&VegjnQKo4`neBnS>sM*_$lk$@?_pzfPB+IU
zG!4|4ylql40e(}6p!F4ctFN`(YiWCXs5mSGc$8*Y1aPE1U4|Y9v<^R4RfGcR+;UuB
z;!17M1$1`ql{DT98}Rjrvgo7ta6p)ru>FWvwWx3)<O%086Z9=WAHDHI+}S^#;v6HI
zeY7o?Qnjkuz&iqd9z1M24o|re?Y;0_C_dW|eDjc$O=eu1(Ee!Quy^Wcmzvx)!8E2U
z6L`r&{LPbR<3@~v1qE2~JAIrSjmEu`8Ay_XK~pz!yWSwaZ|w)i3d)ao1=F1Of!S8g
z`K<BKO^7|WVztMGHN3Psl0pf!21u-6c$Q6U>RcYOI&g}uNB2M2GZAq^YvK9;<KU^5
z#PM31ztT$&a+7RzhozB`TdlKK31gHtw_a?SRP@Lo9XEV#g*H^T1CEL7F*4lR@#gC&
zr_vqkiZ3rNP+?6Z4*L$W6gbewYU~@1(|jwwNeL#4iItYtb`p%`G4uNlrEnNuKB)KK
z4R4<{0le^-skMTRw`KO$W1>u=st4ttN!}Wb#mAu>4@mcXb6{MKB5uRGy03vZtAIX~
zz!AMn-1X-HCR9yFA1OQd4=bsF{qVy@;14C!HPrr@iy0tViHHkR!`H&*1!dZ_NluR#
zU#SUOPMG$7wal0KU?=J;LUeVSC-k=@FXm1#toO?2QqV{Lu;nbT-qvk3u^Lauqj|R)
zZ?$9k0dJu?4X%^59#L$cKP=dY{8{bDQ@G!83ra&!FsMjB0_^k=lUB)4;4EY_DkHCh
z4i>W9#e0pzYeO4^`8%qgz}u?XO{*MxD7eG4q!&fez@~MIk!Oce00)_q<z|*Dm;w*s
zfPfl!7%mM-287z807DF@kbtOl?-#hxqs#X_F68kPY(7&KL;u=5UpKNs%E(YXrO37P
zf&<8_t^Q-}=UEU?vJn<TUtGw+2An29CC?i30MeBK*SemimIHGI)b;5amtq9N010jM
z<A`h+3zxS3%~1?C?YM+|hnvokk6E9A`|EeuFQI0g6^9ZoceaP~F(Nw?ab0XgfV5MU
z-M<vZa$xFRg33F}xQ;p)q3C)?NN0k19DLm92YgbEBS?)+11Ww|9FZsoNb4VGJq2Tc
z_Y1PQ*MX_W#%#e(4R%!&hmK^+16f?)qa)I=zzzj6Z}9O64S0)&U@&!*Z43Uz!A3mt
zBPEa}20l)0q(Xjb;GM6C>dqaZV%Wm#r1&Z!8{ny~pLG_?yLU1e4DiX|-cwMC*A)WC
z?H%5W5llvS8H8V`ASN`p0$i|a>ctK~iWK+^a7odYpcKT+l3TGO|MAKoZEp{Fn66p@
zr~|~o%Dj&o8cv=Vh+N?sqJYe-$Eck26$%J<T!Gw-e0>8TFVG(oS&2mDCI9_(J$~F>
zDmuu1+k=vX(ur}#Y3Gq2;`P%NFU)_AyE{qFsgRmFARcIe337J^kFQUhTLAuTJ~#et
z{_on+?(}Y>@7-6bP_>xuj;+;>FQ7{+d!B0%g5fW{!C<`V&A{)^V|)D2=WrX*Tb`s+
z#@$j!9u8m5Q8-4lPO~F)ejY#|T&|PaOr&-|o*qbvi_QVy?P#Md3e`x&bC*KjQMJH3
zj}`iMCoX2oSFnZCy<+Z#;nO<^6f#TtWYXPxvutR_+o}8%h91QWV>K=X-YlS}$j>`K
z(<e&go?|6)4)CV{fc$wfrb8VmBPU_aT{ROqnov7$yM)0qFhVDGKoBJ$RStY|9(cJT
z+=eoG;sJRPr^_84o7>>QJ*WX*9sqna+jvyKr1TO<J+Hl4R1il&+m@{+WEp$7c(LXD
zuOjV0k%^-rVTaimP@<&g{>*+w5Ih!d97Q@|{DZN@Q-ddcIRJg_`|$N7<`q;UHkU_)
zaL@=ZJz20~Z37H;ntQTfTK0(hWLtiUG)#fht?#~c0G^L0K?|zx3^u6yQuIhPkk;cH
zPlk6-&y`B<JbjaXvS9}CR`*kRCp2i_ZoTpZjN``QfWJ$ivv}Zi!u8u~WSo?2#g~*(
zk+j|4LdS`z$7;wSBUf#K0aUNX)St^l&G`eS8`}U(M=G^dyD-tvPzAi7b~w-_2P-x-
z;9pu9g#JaL8><R|2625r+rXX$8osU4U}RG{b>3k*M93Mx@NJ@DI~9NQX9BH%*Pn?|
zoY>H*UByiYP{*6!i9bznK0e8&nhkFnaX~r!S-Nu~6Zl5+TPAR0|JS4gahWWgS?{RC
zdN0!me;f6{bX6TDSI?{h%WMSEAICyFj|eF`XdX_jFS-JM7Uh(Jtn$Nx2S&dC2dQ3j
Ag#Z8m

literal 0
HcmV?d00001

diff --git a/docs/tutorials.md b/docs/tutorials.md
index abf347fc..861c7081 100644
--- a/docs/tutorials.md
+++ b/docs/tutorials.md
@@ -25,6 +25,11 @@ Step by step guides to coding your @boardname@.
   "description": "Use the color sensor to follow line or detect colors",
   "url":"/tutorials/color-sensor",
   "imageUrl":"/static/tutorials/what-color.png"
+}, {
+  "name": "Ultrasonic Sensor",
+  "description": "Use the ultrasonic sensor to detect obstacles",
+  "url":"/tutorials/ultrasonic-sensor",
+  "imageUrl":"/static/tutorials/object-near.png"
 }, {
   "name": "Infrared Sensor",
   "description": "Use the infrared sensor to detect objects",
diff --git a/docs/tutorials/infrared-sensor.md b/docs/tutorials/infrared-sensor.md
index fd5d6b75..5203ec4e 100644
--- a/docs/tutorials/infrared-sensor.md
+++ b/docs/tutorials/infrared-sensor.md
@@ -4,12 +4,6 @@
 
 ```codecard
 [{
-  "name": "Object Near",
-  "description": "Detect if objects are near.",
-  "cardType": "tutorial",
-  "url":"/tutorials/object-near",
-  "imageUrl":"/static/tutorials/object-near.png"
-}, {
   "name": "Security Alert",
   "description": "Build an security alert using the Infrared Sensor.",
   "cardType": "tutorial",
@@ -20,5 +14,4 @@
 
 ## See Also
 
-[Object Near?](/tutorials/object-near),
 [Security Alert](/tutorials/security-alert)
diff --git a/docs/tutorials/ultrasonic-sensor.md b/docs/tutorials/ultrasonic-sensor.md
new file mode 100644
index 00000000..b9507073
--- /dev/null
+++ b/docs/tutorials/ultrasonic-sensor.md
@@ -0,0 +1,24 @@
+# Infrared sensor
+
+## Tutorials
+
+```codecard
+[{
+  "name": "Object Near",
+  "description": "Detect if objects are near.",
+  "cardType": "tutorial",
+  "url":"/tutorials/object-near",
+  "imageUrl":"/static/tutorials/object-near.png"
+}, {
+  "name": "Wall Follower",
+  "description": "Follow a wall at a distance using the ultrasonic sensor and a proportional controller.",
+  "cardType": "tutorial",
+  "url":"/tutorials/wall-follower",
+  "imageUrl":"/static/tutorials/wall-follower.png"
+}]
+```
+
+## See Also
+
+[Object Near?](/tutorials/object-near),
+[Wall Follower](/tutorials/wall-follower)
diff --git a/docs/tutorials/wall-follower.md b/docs/tutorials/wall-follower.md
new file mode 100644
index 00000000..0d70c950
--- /dev/null
+++ b/docs/tutorials/wall-follower.md
@@ -0,0 +1,191 @@
+# Wall Follower
+
+## Introduction @unplugged
+
+This tutorial shows you how to use the ultrasonic sensor to 
+move a [EV3 Driving Base](https://le-www-live-s.legocdn.com/sc/media/lessons/mindstorms-ev3/building-instructions/ev3-rem-driving-base-79bebfc16bd491186ea9c9069842155e.pdf)
+along a wall.
+
+Your ultrasonic sensor should be placed horizontally, near the driving wheel, facing the wall.
+
+## Step 1 Measure distance
+
+Declare a new variable ``distance`` and store the distance from 
+the ultrasonic sensor on port 4.
+
+```blocks
+let distance = 0
+forever(function () {
+    distance = sensors.ultrasonic4.distance()
+})
+```
+
+## Step 2 Show distance
+
+Use a ``||brick:show value||`` block to display the distance value on the screen.
+This is **very** helpful when you are debugging your code on the robot.
+
+Once your code is ready, download it to your robot and check that the measured distance looks ok.
+
+```blocks
+let distance = 0
+forever(function () {
+    distance = sensors.ultrasonic4.distance()
+    brick.showValue("distance", distance, 1)
+})
+```
+
+## Step 3 Goal
+
+Declare a new variable ``goal`` and assign it to ``10`` in ``on start``. 
+The value should be the distance in centimeters between your robot and the wall.
+
+```blocks
+let goal = 0
+goal = 10
+```
+
+## Step 4 Compute Error
+
+Declare a new variable ``error`` and assign a difference between ``distance`` and ``goal``.
+We will use this value to determine how much the robot needs to correct its trajectory.
+
+```blocks
+let distance = 0
+let goal = 0
+let error = 0
+goal = 10
+forever(function () {
+    distance = sensors.ultrasonic4.distance()
+    brick.showValue("distance", distance, 1)
+    error = distance - goal
+    brick.showValue("error", error, 2)
+})
+```
+
+## Step 5 Show Error
+
+Just like ``distance``, use ``||brick:show value||`` to display the value of the error (line 2).
+This will allow you to debug your code while it is running on the robot.
+
+Download your program to the robot and check that the error goes to ``0`` when
+the robot is around 10cm from the wall.
+
+```blocks
+let distance = 0
+let goal = 0
+let error = 0
+goal = 10
+forever(function () {
+    distance = sensors.ultrasonic4.distance()
+    brick.showValue("distance", distance, 1)
+    error = distance - goal
+    brick.showValue("error", error, 2)
+})
+```
+
+## Step 6 Kp
+
+Declare a new variable ``kp`` and assign it to ``1``.
+This number determines how to convert the error into a ``turn ratio`` for the steer block.
+For starter, set it to 1 and we will go through the steps to tune its value later on.
+As usual, also use ``||brick:show value||`` to display the value of ``kp`` on the screen (line 3).
+
+```blocks
+let distance = 0
+let goal = 0
+let error = 0
+let kp = 0
+goal = 10
+kp = 1
+forever(function () {
+    distance = sensors.ultrasonic4.distance()
+    brick.showValue("distance", distance, 1)
+    error = distance - goal
+    brick.showValue("error", error, 2)
+    brick.showValue("kp", kp, 3)
+})
+```
+
+## Step 7 Turn ratio
+
+Declare a new variable ``turnratio`` and store the product of ``error`` and ``kp`` in it.
+Also use ``||brick:show value||`` to display its value on screen.
+
+Download the program on the robot and try moving the robot around the wall. You should see
+the value of ``turnratio`` change similarly to ``error``.
+
+```blocks
+let distance = 0
+let goal = 0
+let error = 0
+let kp = 0
+let turnratio = 0
+goal = 10
+kp = 1
+forever(function () {
+    distance = sensors.ultrasonic4.distance()
+    brick.showValue("distance", distance, 1)
+    error = distance - goal
+    brick.showValue("error", error, 2)
+    brick.showValue("kp", kp, 3)
+    turnratio = error * kp
+    brick.showValue("turn", turnratio, 4)
+})
+```
+
+## Step 8 Steering
+
+Add a ``||motors:steer motors||`` block for ``large B+C`` at 35% and place the ``turnratio``
+variable for the turn value.
+
+Download the code to your robot and try it out. Does it follow the wall?... 
+Not really, this is because we need to tune the ``kp`` variable.
+
+```blocks
+let distance = 0
+let goal = 0
+let error = 0
+let kp = 0
+let turnratio = 0
+goal = 10
+kp = 1
+forever(function () {
+    distance = sensors.ultrasonic4.distance()
+    brick.showValue("distance", distance, 1)
+    error = distance - goal
+    brick.showValue("error", error, 2)
+    brick.showValue("kp", kp, 3)
+    turnratio = error * kp
+    brick.showValue("turn", turnratio, 4)
+    motors.largeBC.steer(turnratio, 35)
+})
+```
+
+## Step 9 Tuning kp
+
+As mentioned in a previous step, we need to find the right value for kp so that the robot
+follows the wall properly. This tuning can be tedious so we are going to the brick buttons
+to speed up the process.
+
+Add ``||brick:on button||`` blocks to handle the left and right button pressed. When left is pressed, change ``kp`` by ``-1``. When right is pressed, change ``kp`` by 1.
+
+Download your code to the robot and change the values of ``kp`` until the robot follows the wall. (Tip try something around -5 / -10).
+
+```blocks
+let kp = 0
+brick.buttonLeft.onEvent(ButtonEvent.Pressed, function () {
+    kp += -1
+})
+brick.buttonRight.onEvent(ButtonEvent.Pressed, function () {
+    kp += 1
+})
+```
+
+## Step 10 @unplugged
+
+Well done! Your robot is using the ultrasonic distance
+to correct is trajectory using a proportional controller!
+
+The robot will be more precise if it goes slow... Try using a variable
+and the brick up and down events to control the speed as well.
\ No newline at end of file
diff --git a/targetconfig.json b/targetconfig.json
index e9eeddfb..4d4c3b58 100644
--- a/targetconfig.json
+++ b/targetconfig.json
@@ -13,6 +13,7 @@
         "Motor Tutorials": "tutorials/motors",
         "Touch Sensor Tutorials": "tutorials/touch-sensor",
         "Color Sensor Tutorials": "tutorials/color-sensor",
+        "Ultrasonic Sensor Tutorials": "tutorials/ultrasonic-sensor",
         "Infrared Sensor Tutorials": "tutorials/infrared-sensor",
         "Design Engineering": "design-engineering",
         "Coding": "coding",